(1 to 100 of 218 replies)
madeinoz PRO 1:14am, 20 September 2007
Having my camera for just under 6 months and an avid follower of stobist (not to mention being a self confessed geek :), I've been pondering an alternative to the wireless triggers out there. Ebay triggers, great and low cost entry, but problematic and the top of the line wizards, fantastic, but way out of my price range and probably for most other strobists out there.

How about those of us interested getting together and designing our own. I have some skills in electronics and micro hardware and software design, so I bet there are a lot more strobists out there that have the skills required so that we can design something for us as a community.

My idea is initially to get together a low cost DIY modular digital wireless solution - wireless master and slave units. Possibly using off the shelf modules e.g. xbee modules, pic or atmel processors. These would give us the range, reliability and be a reasonable cost. By moving to a digital solution we should be able to move away from false triggers etc, also add a few other niceties like trigger groups, delays and whatever else we want etc

Looking at big picture stuff we could eventually get a bit trickier and look at canon and nikons protocols and bridging between these, i.e. using nikon strobes with canon cameras and vice-versa, or a mixture.

Anyway I thought I'd throw the idea out to the group and if you're interested let me know, it would be nice to pool resources on this.

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(1 to 100 of 218 replies)
Matt Reeve Photography 11 years ago
I would love to be involved with this. However, my skills are not in the electronics, but I am a web developer by trade. I could offer my web knowledge if a website is eventually needed.
elv0000 11 years ago
This would be awesome!

People keep going on about the expense of putting something into production (which is fair enough) but it would be great to have a kit that hobbiests could possibly solder together, or even if we could just buy the circuit board and sort out the case, battery pack and antenna etc ourselves.

Have you seen radiopopper.com He's apparently developed an I/ETTL radio system and he give the impression he had no electronic knowledge.

I know nothing about electronics but would help out any way I could. Theres been a few other people working on the idea but I don't know if anyone has open source intentions.
god hates math 11 years ago
I would definitely support this - I'm an avid Make: fan, and though I lack the soldering skills/EE knowledge to make it happen, I'd buy a set in a second if they were made.
kuster 11 years ago
I'd definitely be up for helping. My experience with electronics is basic, I can do simple soldering (though it probably won't look pretty), but if I needed to I could relearn how to read a circuit diagram. I'm good at 'ghetto-rigging' (for lack of a better way of putting it) stuff to work, so anything I can do to help, I'm in.
greyhills2 PRO 11 years ago
allow me to add my lack of talent to the pool of resources. i'm down to offer whatever i can.
strobist PRO 11 years ago
I love it. I'm in for free advertising for a reasonably priced kit. (Board and components.) It's the very least I could do.

One thing is certain: The folks at LPA either (a) just got a little nervous, or, (b) are laughing their butts off.
kuster 11 years ago
Is there somewhere we can go to learn how some of the current equipment is actually working? Get an idea of what were doing, or even find someone who's reverse-engineered a product already?
flashgordo 11 years ago
There are X number of frequencies being used by the triggers. Why can't there be one which is adjustable/programable? I ended up with a Quantum unit which has to use Freewire. I have four PW's. They don't talk to each other. I can't even use the Freewire to successfully sync the PWs beyond a 20th of a sec.
h_oudini 11 years ago
I am an Electrical Engineer and I do a lot of software development. A PIC processor would probably be the easiest route (well that coupled with a transceiver IC of some sort). I've been thinking about this for a little while now, and I'd love to take part in it. Go ahead an PM me and maybe we can get some ideas written down and start researching parts. I would think that a quick search at Maxim or Analog would turn up some good ICs we could use. Perhaps someone in the group knows where to buy hotshoe components?
danielburkhead 11 years ago
I'd be willing to help out as well. I've got some ***limited*** electronics experience, mainly aircraft systems, but I may be able to answer/help some.

this is a great idea.....Open Source! Sweet!

One question that immediately comes to mind, though....what regulations/rules of the FCC will apply to this little project?

DH - That would be a GREAT thing! (advertising, that is)
bernard.leung 11 years ago
I'd offer to help, but the only thing I know how to do from scratch is make a ball out of elastic bands.
strobist PRO 11 years ago
Trolling for geeks on the main blog now...
hallowed board [deleted] 11 years ago
I am good at locating sources and parts and I would love to be involved.
strogg 11 years ago
I'm in.

I've got some experience with AVR/atmegas (what's on the pocket wizard board), a bit of wireless experience and just getting into some of the board design and layout type stuff. Also a big opensource fan as well. :)
aback expert [deleted] 11 years ago
this would be so cool! not sure what i can contribute but i'm willing if needed! i co-own a small company that makes CNC-machined plastic parts for inline skates, if we need a case/box or something else machined up i could have our guy do it...
madeinoz PRO 11 years ago
Well looks like we have enough interest to get the ball rolling...I'll start posting some ideas on my blog (which has been lacking a bit of love lately) and get an initial mailing list / forum up, then we can get the ball rolling from there. I'll post the address shortly.

As far as FCC and any other Regulatory bodies (BTW I'm Down Under), I'm looking at using existing modules i.e. xbee or similar that plug into various microprocessors that are already FCC approved to use open/unlicensed spectrum, i.e. 2.5GHZ , 5GHZ and 900Mhz . As far as other licensing / approvals we will have to wait and see, but the whole idea is an affordable DIY design where anyone can source the parts etc yourself, or even improve upon the design and pass it back to the community.

timmui Posted 11 years ago. Edited by timmui (member) 11 years ago
I'm in. Just finishing up my EE/CE degree now. Stuck here for two stinkin' classes. Well, one of them happens to be antenna transmissions. Imagine that?
Super awesome idea! I really have nothing notable to offer but wanted to commend you on your idea and desire. If you need someone to stick a wet finger in to see if you get shocked let me know, and I am insured!
madeinoz PRO 11 years ago
For those who feel they can't contribute because they don't understand electronics etc - Hey! I lack skills in many areas (hence why I love stobist), but hey that why as a group we can all contribute in our own way.

Already I can feel the momentum starting to grow (and my wife cringing :)

tuthdoc99 11 years ago
I'm interested but have little electronic experience. If it turns out to be hard as pulling teeth, I'm your man ;)
www.codyleehanson.com 11 years ago
Ok this may sound a bit idiotic, but can someone explain the "open source" idea? Thx
elv0000 11 years ago
No offence Stephen but I think it would be good to keep the forum and discussion here to get as much attention as possible?!!

Regarding sourcing hotshoe components you can get these metal hotfeet of ebay (and Flash Zebra) quite cheaply www.flashzebra.com/hotshoe_adapter.shtml
That would do for the transmitter but I would just want a miniphone socket for the receiver like pocket wizards and skyports.
fir3bird 11 years ago
Sounds like a good idea to me. The i/eTTL should be achievable. I was only a technician but much of my experience was in RF and data communications. I'm also a ham radio operator so I'm at ease with radio comms. But.... I'm far from a EE or design engineer. The first goal would seem to be deciding what we want of our system. Trigger only, or i/eTTL capability? IR or light pulses from a Nikon CLS camera or master flash could be converted to pulses and radioed to the distant end and converted back to IR pulses. As for trigger only I don't think we're gonna beat the price of the Chinese. It' s gonna be fun to see how all this works out.
strogg 11 years ago
Cody: it means that the plans to build the trigger will be available to anyone.. which is really awesome, because then people can look at your ideas, improve upon them, build their own variations. You get the benefit of the entire world helping you build your project.
elv0000 11 years ago
As for trigger only I don't think we're gonna beat the price of the Chinese.

I don't think thats the goal... its more like to match the price + a bit of your own labour to make something more reliable.

An I/ETTL system would be awesome but maybe just a rock solid simple trigger would be a place to start? maybe keep them 2 seperate projects?
ambitious sneeze [deleted] 11 years ago
Open source basically means that the 'source' of the project is avalable to the community. 'Source' can be computer code, blueprints, templates, or IP. Companies protect their profits by keeping this infomation seceret, so that they can hold a monopoly on the sales.

Open source types share all their ideas among their community, allowing for many groups to develope the idea. It generally makes for a much better (be it cheaper/faster/more secure/etc) product.
Jim Allen 11 years ago
I have a machine shop in my garage and can build one-off parts for development if needed. Once a design's finalized, aldolega can setup the CNC for a production parts run. I can also do assembly, soldering, basic testing and troubleshooting if it helps.
Josh Bowers PRO 11 years ago
Sounds great to me.

I make websites and do advertising currently but I've had products made offshore in China so if you need some help getting parts cheap I can point you in the right direction.

Or if this became a group thing where the strobist people wanted to buy a bunch in bulk made off shore I could help as a sourcing agent. I mean for those out there who don't know how to solder, etc, but wanted a middle class trigger. More reliable and higher quality than the current Chinese triggers, but cheaper than the PWs...
tuthdoc99 11 years ago
I personally don't care about I/ETTL but if I could build something myself comparable to a PW set for a lot less money, I would love it.
Francesco Gallarotti 11 years ago
funkworks 11 years ago
Count me in. I have some EE experience and I've been coding software for 24+ years ... including hardware drivers back in the day. I have recently been modding 283 flashes and ebay triggers and have found some interesting radio trans / receiver combo's on the web ... from china of course.
funkworks 11 years ago
I say we use the KISS principal here. Let's get a working, rock solid slave then deal with the I/ETTL when we get there.
madeinoz PRO 11 years ago
I agree get the basics working then add the fruit, and cause it's open source, you can add what you like.
geerlingguy 11 years ago
I agree with funkworks—start simple, expand from there. The first goal would be to create (a) a transmitter to stick in your camera's hotshoe, and (b) a receiver to fire off your flash.

One of the most convenient aspects of the system, IMHO, would be having a mini-jack, PC sync jack, and LED that all triggered on the receiver.
J0hno 11 years ago
Depending on where this goes, I'm interested in being involved. I've done a bit of RF and work with microcontrollers and HDL.

If it's just about reliability, it may be an idea to build something compatible with the YH triggers, and so make it possible to use their transmitters coupled with an improved receiver.
randymor 11 years ago
I agree with funfworks ... build the basic ... then add other options.
I studied electronics (in aprevious life) am now a Supervising Electrician, but still dabble in electronics, and Love Photography.
I have also gave this some thought as some others have, and think an open surce approach could make it happen in a short ammount of time ... count me in.
infxualbydesign 11 years ago
personally i think this should go simple trigger ( pocket wizard style) as being an pround olympus shooter i tend to think we may get overlooked if this goes the i/e ttl route. just my $0.02
Crantastic 11 years ago
Ditch the I/ETTL but keep the TTL capability. I've thought about this for a while. Calibrate the reciever to the flash and utilize the "off" part of the hotshoe on the flash. Then each reciever could be set individually from the camera what power to use. There would be a "synchronize" switch that the user would manually hit to change the power settings of each individual reciever. The transmitter would be user-friendly with just 4 slider dials indicating power. No freakin buttons or menus.
dmgerman Posted 11 years ago. Edited by dmgerman (member) 11 years ago
Wii Remote

I have used the wii remote as an input device attached to a camera to do perspective correction (see turingmachine.org/blog/index.php?/archives/14-Using-the-W.... The WiiR supports commands from the computer.
It should be possible to get the computer to trigger a WiiR function (such as feedback) and drive a transistor to fire the camera (I implemented something similar many years ago a small device to fire a Canon camera using the parallel port of the computer).

The Wii is cheap, and its bluetooth. The bluetooth has a very good range.

eyenology 11 years ago
Definitely interested. I couldn't contribute much to the actual design of such a beast, but would be able to tinker enough to put together a kit.
bubarker 11 years ago
Please add me to the group
Yet another Dave 11 years ago
I'd be interesting in contributing in whatever way I could... I'm a software engineer, but my education was a combination of (mostly) mechanical, (some) electronic and (a moderate amount of) software engineering. I'd got a little bit of experience with VHDL and microcontroller programming from uni, and some soldering.
jeremey 11 years ago
I'm a software guy but I'm not thinking that'll be of much use... so instead I'll be happy to complain about whatever is produced.

For my first complaint, please be sure that "strobist" has an "r" in it. Aside from it being talk like a pirate day, it really does have an "r". ;)

(I know, probably a typo, but I'm just saying...)
albnok 11 years ago
Add support for Minolta/Sony because Minolta started the whole wireless TTL thing please? :)
www.codyleehanson.com 11 years ago
Thanks for elaborating Strogg. After understand the open source term now, I really like the idea. Wish I had more experience to be able to put my $.02 in.
funkworks 11 years ago
Flash duration is controlled by varying an internal resistance on most flashes, not by turning the flash off at a set time. You could use a remote controlled potentiometer (just like the one that controls your stereo receiver volume) to set the resistance for a particular flash. It would, however, require a flash modification and would be very difficult to build a universal system that would work in that way.

I still say KISS is the way to start.

We can burn the other bridges when we get there :).

Just my .02
BigJohnny2K Posted 11 years ago. Edited by BigJohnny2K (member) 11 years ago
Count me in! I don't have a lot of EE experience (though I minored in it years ago), however memories hearkening back to my digital logic days have been swimming through my head since I started reading this.
Benny Vision Posted 11 years ago. Edited by Benny Vision (member) 11 years ago
Any chance on this thing being capable of working with a pocket wizard (triggered by PW) incase someone happens to have 2 PWs already and wants more?
expeditionmax 11 years ago
I am not an electrical engineer (I r mechanical!!), but I would reckon the easiest thing to do would be to find a radio transmitter setup that is already in use in some other application and then adapt it to our purposes. That way, the computer chips would already be built and good to go. Then make up the housing, program the little guy, add a solenoid or two and that would be it.

I think if you took a stroll down your local toy stores' radio controlled vehicle isle, you could conjour up a few ideas that would save A LOT of time and probably money. Pick out one of the toys that works good, then find out who makes the chips. Give them a call and they could probably hook you up with the chips already manufactured. That way, you save a lot since the most complicated component is already assembled.

I just had a really good idea. Get some walkie talkies and modify them to work. It might be a little goofy looking, but I would think they'd work good.
madeinoz PRO 11 years ago
Initally I think we need to be able to trigger via camera hot shoe and remote units receive and trigger the strobe. I would think not that hard. basically a remote switch then expand from there.

I would like to see the units to be able to be used as either a transmitter or a slave, a flick of a switch decides it's role

So to start the ball rolling on some requirements-

Min workig Distance? 30m line of site?

Max Number of units? heck 4 is more than enough for me. however 16 32 all possible.

Able to change select channels, need to have a look and see what spectrum is available for channels etc.

What Frequency? 900Mhz will give best non line of Sight, but each have their advantages etc commenst please

Initial I/O requirements for unit

DIgital inputs -
Hotshoe trigger - From camera
PC Sync Trigger (From Flash Meters / Camera)
Manual trigger - (Test Push button)
Mode switch (master/slave)
Channel Select (depends on how many channels are available)

Digital outputs:
Strobe Trigger (Hotshoe)
PC Sync Trigger
Contact Closure (remote switch for camera trigger if required)

Other possible I/O
RS-232 Serial (for flash upgrade / programming etc)
I/R Receiver
I/R Transmitter

Compatible with stock AA NMIH Batteries that a good stobist carries in bulk or do we want something smaller and more compact? My thoughts are stick with what we already carry.

Jon_Senior 11 years ago
@Benny: Probably not as this would involve reverse engineering the PW protocol. Not the best route to take on a KISS project.

Count me in. I have some limited experience with those little prebuilt RF modules and have written code for various uCs. I was looking at this last night (Having just bought a 16 channel eBay set) and wondering how easy it would be to make it reliable.

Initial thoughts: The plug in RF transmitter / receiver modules are cool (And not entirely dissimilar to what you'll find in your eBay units), but do limit you to one frequency. A more customised design might be necessary if you want change frequency to avoid interference.

On that note the "free" frequencies tend to vary from country to country, so some level of selection would need to be available to avoid having units confiscated by over-zealous radio officials.

elv0000 11 years ago
Regarding the I/ETTL thing - its not just about TTL but all the remote functions like setting your flashes power remotely and high speed sync.

I'm with the start simple mentality but it just may be there are enough people clued up to make a transmitter that just transfers the ttl light pulses into a radio signal (just as radiopopper claims to have done).

So it doesn't matter what camera you use as all its doing is converting the existing signal to radio. And the basic dumb trigger (like pocket wizards etc) is just a side product of that so you can trigger anything from the regular PC signal. Then all multi group/channel stuff etc is handled by the camera (if you wann use the fancy gear) otherwise its just a simple trigger.

A basic reliable trigger would be a great start though (and obviously not a simple task in itself).

(PS - the day you Sony, Minolta, Olympus etc people give in and buy a popular camera is the day half your migrains will stop... Ive tried it it works :-) )
madeinoz PRO 11 years ago
expeditionmax: The problem with the approach of using an existing transmitter i.e. one from a toy is basically that is what is being used for the ebay triggers, hence interference and false triggers.

What I'm proposing is to use a prebuild module where the brains plugs in (what we develop) but a bit more advanced, however they are available on the market at fairly reasonable costs that handles the underlying RF/Error detection/recovery to prevent the false triggers and make the whole setup more reliable.

If we go digital then not only do we have the error checking etc but we can assign our "network" of stobe units their own ID, so that if someone else is on the same channel they will more than likely have a different ID so they won't false trigger your equipment, also RF interference from other sources (I know my garage door triggers my ebay units) will not false trigger. So we have channels and IDs to make things more reliable.

madeinoz PRO 11 years ago
Possibly these or something similar as underylying RF module

Johny Manic 11 years ago
Bluetooth is defiantly the key here, as one user mentioned. It is fast and very reliable, and the tinkering kits are readily available through the back pages of Make magazine. Another strength of bluetooth is the ability to encode a signal, or series of signals to disallow a false triggering.

I will post more resources as I gather them.

madeinoz PRO 11 years ago
@Johny Manic: Bluetooth definately a contender in my books, but what about range? probably great for most situations.
FlashZebra Posted 11 years ago. Edited by FlashZebra (member) 11 years ago
No PC connector on anything.

Forget ETTL, iTTl. Just get a basic radio slave set.

Save all that TTL stuff for version 2.

Enjoy! Lon
frozen_bike 11 years ago
I am with elv0000 on this one, changing the IR pulses into radio waves and back to IR would be number one on my importance list. I believe that this would be useful to Nikon, Canon and Pentax users - although it would require a modern flash.
I would add the simple trigger function as the second goal. I can trigger dumb slaves with one of my remote flashes if I need to, but most of the time I like to control all my flashes from my camera and not walk over to my slave to adjust it.
Also, I am an accomplished hardware designer / assembly programmer and have worked with both PIC and AVR processors.

Johny Manic 11 years ago
Normal range is nearly 32 feet, but can be extended with off the shelf materials and a reasonable antenna (PW sized).

"Extending Bluetooth range from 30 feet to 3000 feet
madeinoz PRO 11 years ago
@Jonny Manic mwahaha excellent (rubbing hands together)
NevadaJim 11 years ago
Well, consider me a member of this clan. Working open source software engineer, avid AVR programmer, electronics hobbiest, cnc machinist, Extra Class Ham radio op, etc etc.

I'd argue that the correct way to do this is encoded, so we can used an unlimited number of these in the same area and not interfere. Plus, I'd love to see it be 2-way.. so that we get get a green-light/red-light telling us if the strobes are charged, etc.

The link-layer stuff should already be done with zigbee and friends. Off the shelf xcvr modules are expensive ($30) but not bad compared to PW2's
guomo 11 years ago
I'm in. I've got analog design and software background. My first suggestion is a spec. So here goes (funny, looks a lot like the back page of a PW manual ;-):

Frequency: 344.04 Megahertz
Transmit output power: Less than 0.001 watt (1/1000 of a watt or 1 milliwatt)
Minimum receive Contact Time: 80 milliseconds
Maximum Frames Per Second: 12
Top Ports: 3.5mm (1/8") mono miniphone
CAMERA / FLASH Port Voltage Handling: up to 100 Volts
FLASH Port Voltage Handling: up to 200 Volts
CAMERA / FLASH = center positive; FLASH = non-polarized
Both ports are current limited: 4 Amp peak, 250 millamp continuous
CAMERA / FLASH Port and hot shoe mount voltage present: 3.3 Volts DC.
A camera is protected from a flash connected to either port.
AC Adapter jack: 3V DC 200mA (unregulated), Center Positive
Male plug connector required: 1.3mm ID, 3.4mm OD, 1cm long
Body Dimensions: 1.4" deep x 2.1" wide x 4" tall
Antenna: 2.4" tall, 0.3" diameter
Weight: Less than 5 ounces with alkaline batteries
Operating temperature: above -15° C (5° F) and below 50° C (120° F)
Storage temperature, without batteries: above -30° C (-22° F) and
below 85° C (185° F)

The items in italics are negotiable/optional. Can we agree on a spec first gang and then we can start sourcing parts. Without some basic constraints and project goals like this we'll all sit here and just geek out and get nowhere.
GomoX 11 years ago
I don't think Bluetooth is a good idea. It's expensive and it's inherently distance limited.
The link posted displays a coffee-table sized antenna - not a good idea for something you mount on your hotshoe.

Eventually if you need computer control, then a bluetooth enabled transmitter module should be a no brainer to make.

I am no EE, I'm a CS student, but I have done quite a bit of analog electronic projects and some digital microcontroller processing too. At the very least I can beta test :) (and complain about stuff like Bluetooth).
cankleswebb 11 years ago
has anyone tried fm?

transmitter cgi.ebay.com/Car-FM-Radio-Boardcast-Wireless-Transmitter-...

reciever cgi.ebay.com/Mini-AM-FM-Portable-Pocket-Radio-Headphone-B...

and all in that 3.5mm we love

anyone game to try it?
o7photographs 11 years ago
I'd love to test / test build... No electrical engineer but have the basic knowledge.

Other thing I could do if things get rollin' is set up a webshop, maybe we could even get a development webblog and stuff, wordpress is easy enough to set up. Would be cool to see progress, and have a central communication point.

On the specs: I'd like to have a receiver that can also run on 6V so I can power it from the SLA's I'll use for the flash.


strobist gel packs available!
NorthwestWolf 11 years ago
While Bluetooth may be a bad idea due to cost and power consumption, Zigbee (802.15.4) might just be the ticket. The networking ability of Zigbee could allow for rather creative and powerful slave functionality.

A quick overview of Zigbee: en.wikipedia.org/wiki/Zigbee

I'll post a bit more after I get some sleep, but I'd be more than willing to help out in any way I can. I have a background in programming and have taken up hardware programming/hacking in the past year.
larkollen07 11 years ago
Great initiave! I would like to see different methods of triggering, ie by sound, light beam or what ever by simple plug in of say a mini jackplug. And how about being able to trigger the camera electronically as well. There are various ideas on the net for alternatives to the expensive Nikon MC plug.
madeinoz PRO 11 years ago
ok I've quickly setup a wiki to start gathering this information until we get a domain/website up and running.


Discussion can stay on this thread if you like or on a seperate mailing list, eitherway I'm not too fussed. My preference is via a mailing list that way I don't usually miss things. What are ppls thoughts?

Anyway create yourself an account on the wiki and go for it.

BTW we need to name this thing. Couple of ideas SWOT or OWT?



sτενεωooδroω Posted 11 years ago. Edited by sτενεωooδroω (member) 11 years ago
Freshly minted electronics engineer here... Please add me to any mailing list, etc. that's created for this project.

I've done some board design and layout, microcontroller software development (PIC and ARM), and random other electronics, and would love to help out with this — I've been frustrated with my ebay triggers nearly since I received them.

I have some experience with ZigBee using the MaxStream XBee modules, and I would say that ZigBee is probably overkill for this project , or at least the first iteration (there is a lot of network overhead for our simple application). The name of the game is speed here if you want a reasonable sync speed — the KISS goal is to essentially emulate a PC cord without the wire.

Frequency-modulated RF modules transmitting a digital string encoded in some way would probably do the trick, and I imagine is at least somewhat similar to how a PW would work. Take a look at www.atmel.com/dyn/resources/prod_documents/doc4841.pdf for an example of a potential starting point for the RF side of things.

Keep up the good thoughts everyone — there is potential for a great, well-priced tool here...

Edited to add: Take a look at this if you haven't already for some inspiration from the pros. I for one would be curious to see what devices are under the EMI shield...
madeinoz PRO 11 years ago
@umwoodr0: Probably a zigbee, but would be interested to find out lol
fumbling cat [deleted] 11 years ago
We need a cooler name :)
elv0000 11 years ago
I say keep the discussion going here as much as possible, it would be really sad to see this die in the arse or go way off track :-)

Maybe we could have a competiion for the first person to get an affordable board working reliably.... we all chip in a few dollars and winner takes the kitty! ;-)
curly pail [deleted] 11 years ago
im definitely up for this. i have limited knowledge in the field, but i have a few friends (who sadly are not interested in photography) who might be able to help. i like the idea of a mailing list, but ill be on the wiki very soon.
NorthwestWolf 11 years ago
I was checking the website of my favorite component provider, Sparkfun www.sparkfun.com and what should I come across on the front page?

Nothing less than an new FM transmitter module: www.sparkfun.com/commerce/product_info.php?products_id=8452

Sparkfun is also an excellent source for AVR microcontrollers (as used in the Pocket Wizards) and VERY affordable programmers. :)
larsholmgaard_dk 11 years ago
I am all in.

I do 3D illustrations, visualisations, flash animations and applications for living. Let me know if you need assembly instructions, product visualisations or something like that. I'd be happy to help out.

See www.larsholmgaard.dk for examples.
forevermyung Posted 11 years ago. Edited by forevermyung (member) 11 years ago
longtime reader, but thought this was too cool a topic to pass up on being just a passive observer.

I'm just a software guy, and am unsuited for the trickeries that accompany the wiring and packaging part, but from a software/hardware platform, I would like to chime in on the Zigbee front.

In a prior life, I was doing some work with low powered wireless sensor networks based off TinyOS based sensor motes. This was in the early days of zigbee, but it's basically the same thing. The hardware platforms themselves are open source as is the OS and protocol stack.

Some commercial kits for development include:


And the open source OS that runs some of these devices:

These are the ones that I've used. I've used the 433, 900Mhz and 2.4 Ghz versions of the devices. 2.4 Ghz has the most bandwidth, but range isn't as great.

- High overhead, but these small devices can power and interpret EKG and other medical devices, so bandwidth to do TTL calculations or other cool things like controlling flash zoom or power ratios is a big unknown
- Indoor range in my usage hasn't been the best 3-50 meters hit or miss, highly variable...though the power is configurable.
- Learning curve on the OS and protocol design is a bit odd and eclectic.
- wiring and packaging to make it user friendly and configurable and non fragile (see, ebay trigger)...that's the challenge here, be quiet idealistic software guy!

Pros (at least from this cursory, late night brainstorming):
- Open source hardware is easily configurable, hackable. You have a transceiver all ready to be wired up and programmed. The MoteIV board is a mini-SD form factor.
- Open source OS for "easy reprogramming"
- Trivial (software) to just do simple triggering. If you see a packet, then fire the flash! Would solve some of the dreaded ebay remote triggering issues i've been running into (they just pop randomly or don't reliably flash at all)...wiring is another issue
- Programmable QoS in how to deal with uncertainty, etc.
- Configurable power, much less headaches than BT.
Programmability allows for adaptability to flash protocols...relative ease of programming would allow more vibrant geek contributions.

Ideas for ramping up:


Ebay trigger model - broadcast certain packet to trigger flash. Even the basic programmers' examples included in the kits are adaptable to simply and reliably test these things.

Multi flash setup, you can set a dip switch on each one and alter the packets sent out to trigger only certain or multiple groups.

Because the Motes are somewhat configurable, and reprogrammable, conceivably you could "trick" the flash to think it's connected to a camera and in turn control power (easier said than done, camera makers protocol, etc). Then that would allow say a Nikon or Canon speedlight to be an independently, and remotely configurable from a central location. Or, with multiple flashes connected together, just fool the camera shooting that all 5 flashes are just 1 flash, and have them all do eTTL calculations as one (preflash at the same time, camera make a decision, and distribute the light load around the flashes.

Finally, my craziest idea is that since these Motes can also self organize and to a certain extent know relative location, I'm envisioning a wedding or event photographer setting up 10 mounted flashes circling an entire room. Walking around the room, the camera will advertise its location to the other flashes and only ask the flashes that would do an ideal "cross lighting" to trigger...ie, not the ones directly behind or directly ahead. Crazy I know, but I figure if there's something to be done with an open source, community driven project, it should aspire to go beyond reverse engineering something, but truly advance it to something really cool :-)
J0hno 11 years ago
I think the most likely successful approach is to use a basic amplitude shift keying of a code sequence. For the transmitter, that is basically just providing a serial code to something like a Linx TXM-433-LR module. Then the receiver just correlates against that code. BPSK would be better, but then you have synchronisation to deal with as well.

I'd expect The zigbee and bluetooth type ideas will require much more latency for the protocol handling for a given available bandwidth and power. One Zigbee FAQ I found listed a latency "as low as 16ms"... We're looking at needing sub 1ms.
forevermyung Posted 11 years ago. Edited by forevermyung (member) 11 years ago
oh yeah...latency. forgot about that. that was a huge con i neglected to mention. i ran into times much slower than 16ms...so my mileage varied to be "really bad"
KelvinLeung Posted 11 years ago. Edited by KelvinLeung (member) 11 years ago
I'm always a reader of strobist and I just join the club before writing this comment. I'm a RF hardware engineer working on 2G/3G cell phone IC. Our company is the key Zigbee chipset provider. In fact the Zigbee development team sit right next to me.

I understand the frustration of the current solution in the market. We have some high price tag PW (not much in feature) and the extremely low cost Chinese made flash trigger. I don't own the PW but I've opened up the ebay flash trigger and measure the RF signal of it in the lab. In short, there is no encoding in this transceiver whatsoever. I measured the 4 channel version and every time the flash trigger the transmitter, the encoder IC generate a pattern of 8 bits. The transmitter AM modulate the RF signal multiple times (redundancy - error correction) using that 8 bits pattern. The transmitter circuit uses two transistor and a SAW oscillator device. The receiver uses a RF module with several transistors and some passive components.

One of the complaint I have for the ebay flash trigger is the lack of interferer block protection. 433MHz band has some really high power signal in the neighborhood. No matter what frequency band the open source flash trigger (OSFT) operates, we need to have the following to provide from false trigger:

1. Shield to cover the RF circuitry
2. Software encoding to correct transmission error (to reject interferers)
3. Channel selection (prefer digitally encoded as I see several strobists here are capable to write us some code
4. Embedded antenna design to make the OSFT look nice and slick

Regarding Zigbee, Bluetooth as the transceiver, I do think it's overkilled. A simple ASK transmitter will do the job we there is enough error correction in the digital domain. In fact, if we want to go fancy, a display is needed to show the channel/TTL info which will be the biggest task for the entire project.

The original idea is to make it a kit somehow. However, this is the challenge. Almost all of the components are surface mounted and most of the IC cannot be soldered by hand. You'll need to reflow solder them because they don't have pin sticking out. I guess it can be developed but the manufacturing part is kind of tricky. We have a lot of people interested and most of them don't have the tool/skill to assemble such a kit.

The other option is to hack the ebay flash trigger with an MCU to add on digital coding for error correction. We really should start small. Once it's done, we can think about adding TTL signal to the OSFT to take care of major camera manufacturer TTL coding...

Just my 2 cents.
J0hno 11 years ago
Something that will need to be well defined right from the start is the licensing of contributions. I assume it would be modeled somewhat on the GPL. Is the idea that people can build the result of it and sell for profit as long as they publish the schematics and layout of any changes they make?
J0hno 11 years ago
Kelvin - I'd argue that that the sequence of long/short pulses the ebay triggers output is inherently a "encoding". There is different bit pattern for each channel, and that pattern can be correlated against at the receiver. Admittedly, that sequence wouldn't be optimal, and the receiver probably isn't doing as much as it could out of that sequence.

I wouldn't rule out the possibility of hand-soldering. I've seen someone populate a board with a stack of 0402 parts on it by hand - and with no solder mask. Having said that, if this project is to be successful, I'd expect the main way for people to acquire the hardware would be via someone having the boards made and parts machine placed.
ChrisJohnson 11 years ago
The way I see it, our primary requirement is the radio transmitter and receiver system. Since, in the simplest case, we just have to transmit one low-to-high transition for the flash to fire, once we have a wireless transmission system, the rest can be built with a few standard components for voltage conversion etc.

Our requirements are:
- sub 1ms latency
- cheap
- decent range
- low power consumption

While I've done a fair bit with PICs etc., I haven't ever looked into the wireless side of things. I get the feeling that building from the ground up is not usually economical, and that we'd be looking at commercial modules for the transmitter and receiver.
PAAT Posted 11 years ago. Edited by PAAT (member) 11 years ago
So, after reading this and doing a little further reading, it seems like the main issues are:

1. Pocket Wizards are highly reliable for 2 reasons. First, in the US they operate on the uncrowded operating frequency of 344 MHz. In Europe it's 433 MHz. The two are obviously not compatible. Second, they use a fairly sophisticated RF pulse encoding scheme (ASK/FSK -- the ATMEL transceiver) which gives a wide range of flexibility for operating several systems in close proximity. It appears there are at least 32 channels/IDs. Everyone loves PW's, but they're too expensive.

There is a great amount of detail, including circuit diagrams, in a recent 2006 Pocket Wizard patent (US patent # 7133607 -- read it at www.pat2pdf.org).

Read about Pocket Wizard frequency configuration issues here:

2. The inexpensive Gadget Infinity (Chinese) triggers are considerablly less reliable because they operate in the crowded (in North America) 433 MHz ISM (Industrial, Scientific, Medical) band where there are plenty of other devices (garage door, wireless doorbell, etc.). I can't find much information in Google for the parts on the Cactus board but I'm guessing the RF pulse encoding is far simpler than the Pocket Wizard's. Furthermore, there are only 4 or 16 selectable channels so two sets operating in the same room are likely to crosstalk.

These are not patented.

-- --- ---- -----

I think a cheap knockoff, like the Cactus, would be easy to build. Providing the reliability of the PW system is going to be tougher, and will cost more.

However, this is a great idea, let's keep the ball rolling!


After Note: I don't think the Cactus idea is BETTER, I just think it's EASIER! There's no reason to build our own Cactus models, they're nearly free as it is!
Morrijr 11 years ago
My electronic skills have been rusting since college - but I'd love to help...
sesh00 11 years ago
Woah, spend 8 hours driving one day and look at what you miss!

Firstly, I'm a Comp Sci/Soft Eng. background, so I'll be happy to help out when we get the the programming stage. As for electronics, I'm not as into that area of things, but this does sound like an awesome project.

First thing that comes to mind is that it would be cool to have individually software encoded data ie, to trigger the flash, send 'SESH' for me, 'PAAT' for someone else). This could be send on all channels as well.

Bluetooth is a no-go zone due to the latency and lack of range. Not sure about some of the others that have been mentioned either (but that's not really my area).

I think a few of the electronics guys need to have a chat and decide on how to do the transmission - being able to send data along atleast 4 different channels is going to be pretty important. Once that is decided everything should just fall into place.

Another decision that should be made is whether to have transmitters and receivers (ala ebay) or to have transceivers (ala PW's). I personally would love to be able to use them as transceivers, but there are obvious drawbacks to that.

Forget TTL for now (forever for all I care) - lets just get to the point where we can trigger a flash, then worry about the other stuff.

Target price? How about $40 usd/$60aud per kit?

@madeinoz - I'm in Australia (Adelaide) too, so if you need help sourcing parts or testing things locally let me know.
ben-s 11 years ago
I'm interested. I havea fair knowledge of electronics, and I have tinkered with PICs. Not too strong on the RF side though...

I think we need to come up with some kind of fast digital coding, running on a smaller number of frequencies.
Give each transmitter a code, and make the receivers learn that code.

As an example, 2 photographers working in the same area, on the same frequency:
Tx 1 operating on frequency X has the code "123"
Tx 2 is on the same frequency, but has the code "789"
Rx 1a & 1b are listening for the code "123", and 2a & 2b are listening for "789"
Thus if 2a & 2b hear "123", they don't fire, but 1a &1b do fire, because they recognise their code.

There are some problems here, like both photographers shooting at precisely the same time, but I think the probability of that is somewhat remote.

I hope this makes sense :)

I'm in the UK, so maybe on the wrong side of the pond, but anything I can do to help, let me know!
ben-s 11 years ago
Haha. Sesh; you seem to be thinking along the same lines as me.
Tranceivers could be good, but I'm personally happy with separate units - so long as they look significantly different!
jeffegg2 PRO 11 years ago
On the wishlist: It should work with either AA AAA Nimh.
J0hno 11 years ago
Using the Linx TXM-433-LR IC as point of comparison for typical capability from commodity chips, it offers up to 10kbps data rate. That means only 10bits are recieved by the time 1ms goes past. That really doesn't leave a lot of room for a code plus redundancy and noise rejection. An option may be to have different length sequences for different channels - so some are faster and others more reliable.

In order to get good performance though, we may be looking at finding a transmitter and receiver with more bandwidth - in the region of 100kHz.
Jarra PRO 11 years ago
Awesome work :D Just wanted to give you all a pat on the back. What a great thread! Something's cookin!
yourealwaysbe Posted 11 years ago. Edited by yourealwaysbe (member) 11 years ago
I guess there's no need for a theoretical computer scientist?

But hey, i have a cheap soldering iron i've barely used, and always keen to experiment.
last river [deleted] 11 years ago
...with brains like this we could change the world !

(insert evil laugh here...)

I'll gladly make the tea, and supply the biscuits !


Dibutil Ftalat 11 years ago
Hey, I read the whole thread and noone so far has mentioned the car keyless entry remotes. How expensive is the electronic hardware for those?

Although they present a reverse to what is the goal here: multiple transmitters, one receiver that accepts the signal of chosen ones.

Just an idea, for the pool.
ben-s Posted 11 years ago. Edited by ben-s (member) 11 years ago
J0hno; I guess a lot comes down to the range you want... you could go up to a few GHz and have really good data rates, at the expense of range.
How much data do you reckon we'd need to send?
I'm thinking a wake up byte followed by 3 bytes of code.
That's going to be 4 bytes of data, or just under 4ms at 10 kbps
Considering that most cameras sync at 1/200 - 1/250, the shutter is only open for 4-5 ms.
I think we need to get the latency down to 1ms or better if we want to fire close to the midpoint.

jeffegg2; Sounds sensible. I think with an appropriate regulator it should be possible.

Dibutil Ftalat; I've already got a set of them for remotely firing the camera. I don't think they're fast enough for flash. EDIT: I've just checked, and no, they're not. they transmit at up to 4.8Kbps.
Guy Carnegie Posted 11 years ago. Edited by Guy Carnegie (member) 11 years ago
Before this gets off the ground, I just have to say that with all the best intentions in the world, we need to look at this from a commercial point of view.

In my experience engineers and "sales" guys never really get along, and are always blaming eachother for shortcomings or not telling the full story.

I wouldn't aim too high right now, Sure, build the hardware capable of two way communications (necessary for ETTL/ITTL) - the good thing is that these are on different pins on the hotshoe, as well as encoding a "fire" signal into the downstream channel.

For the first version, this doesn't have to be used, so long as it's there for future development.

The software can quite happily monitor the center pin for the fire signal and transmit that to the strobes.

For future development, we can start working on the SOFTWARE for the bi-directional communications. This is where the open source idea comes ito its own.

Does anyone know anything about collaborative development of open source projects?

I'd recommend V2 should concentrate on communicating with ONE strobe.

I'm not sure what the benefits are of ETTL etc where more than one strobe is concerned - won't the metering of one strobe be confused by the preflash of another? Also, we'd need different channels (or ID keying) for each strobe. Obviously we can't change the hardware of the flash itself, but maybe we can "time slot" the preflashes so that each strobe does it separately. This would involve some sort of handshaking ie, I'm finished, your turn. Obviously total preflash time is restricted to the camera shutter latency period.

Has anyone used a Canon ST-E2 with MORE than one strobe? Do you get full ETTL functionality on both strobes?

Laslty, we need to make use of the knowledge we already have of the market. We are alreay very knowledgeable about the benefits, limitations, and features of the Pocketwizards, as well as the Low-end units, such as the EBAY triggers, and the mid-range units, like the Elinchrom SkyPorts (which I've just bought but not tried yet). We need to pick the best bits of all of these, together with our own observations, to come up with something which could perceivable, compete with them and drive forward the wireless telemtry industry.

I'd say we need to get an engineer on board who is very familiar with wireless telemetry and have him/her analse the telemetry from the ST-E2 (and the Nikon equivalent if one exists). Potentially, they should also consider other telemetry brands, such as Pentax and Olympus, and we could have downloadable "firmware" which allows use with any system.

Potentially, we could have custom translators which would use a common protocol between then, but which could have their "external" language set to "Canon/Nikon/Pentax//Olympus" to communicate with their respective device, be it a body or a flashgun.

You guys are absolutely right that we should NOT start from the ground up, but should use as many "off the shelf" parts as possible. This is the only way we will drive down cost and complexity, which is often the two concepts where engineers fall down.

I don't think we need to use a universal combined master/slave, like the PW's, although every unit will still be a "transceiver" as it needs to communicate both ways.

So we'd need two types of hardware -

A Master unit, which will either sit on the hotshoe for TTL, r could be connected to the cameras PC-Sync socket and mayeb clipped to the photographers belt or something. This would need to be configurable for the body manufacturer either through storing multiple protocols which could be switched between - handy for people shooting multiple bodys - or have the firmware updatable so It can "talk" Canon/Nikon etc.

And a Slave unit wihch will talk to the master, and translate the comms back to Canon/Nikon etc.

Of course, you could quite easily then have a Canon master, with three slave units, one Nikon, only olympus, and one Pentax.

Maybe too much detail, but this is quite capable of growing so many arms and legs that it becomes unbuildable.

We are a large community, quite capable of coming up with the ideas, but we need to manage the project it properly.

We are also quite capable of engaging development engineers to do some of this development for us. Btweeen us I'm sure we have the funds needed - ie $15-20 each would give us a working capital of tens of thousands, to pay for someone to design this hardware for us. If ti all goes pear shaped, we've paid twenty bucks and learned a good lesson.

all the best, and of course I'll help wherever I can - even if it's only to try to calm things down a little once in a while.

Lastly, the one other thing we'd have to look out for would be radio transmission regulations - these obviously differ from region to region.

I'm not sure if supplying the item as a kit (which won't work without downloadable firmware) gets around some other regulations - are there any commercial lawyers in our midst?

all the best
ben-s Posted 11 years ago. Edited by ben-s (member) 11 years ago
Interesting post, Guy.
My first question is why do we need to bother with E/I TTL?
The "strobist" mentality steers away from the auto stuff, and I'm inclined to agree with that. Of course, If the majority want TTL compatibility, let'em have it, but I fear that would put the price through the roof...

I totally agree about using off the shelf parts. I think the other consideration is making this project as internationally legal as possible. EDIT: As you've just edited your post to say :)

Why don't we set up a proper group of people so we get a clear agreed design, and not a fragmented mess?
chadworthman Posted 11 years ago. Edited by chadworthman (member) 11 years ago
I'm no electronics engineer (I'm a lowly Unix admin), but it seems latency is much more important than bandwidth. Next in importance is range.

I'd like to say that I think the best approach is to hack the ebay triggers. A good first milestone is to make them as reliable as Pocket Wizards. Some people already have DIY mods for (what they believe) is extending range and increasing reliability. Latency is not an issue with them, with a good set of batteries I can already sync to over 1/1000th.

I also doubt you could build an ebay trigger for less than buying one.

Worry about the (e|i)TTL stuff much later. Though at the heart of any TTL system would simply be sending a start and stop signal to the flashes. I don't believe bi-directional communication is necessary. The key is in fooling the camera into believing it has a IR sender attached. You don't even have to reverse engineer the Nikon or Canon protocol, a good codec to convert IR to radio and back would do the job wouldn't it?

If you could convert any IR sequence to RF then convert it back to IR on the other side, the job is done? How do TV remote extenders work?

Would this technology help? remote extender

What if you put the battery shaped TX unit in an on camera SB-800 and put another SB-800 in another room with the RX unit. I only have SB-28 and older flashes so I can't test it.

Here's an all external unit.
the one and only roly 11 years ago
Am I the only one who is getting visions of the A team?

bluphoto7 I'm a "sales" guy and I get on great with our engineers (and the engineers of our customers), maybe it is just our industry (airlines) where people tend to be more open and less defensive.

this is a great project idea and i can't wait for the outcome. I'm not that good with soldering and such, but I'm sure that one of our engineers would be happy to help me out in his spare time in exchange for a case of the frothy golden liquid stuff :D

Once we have got the wireless triggers sorted what will be next? battery packs?
last river [deleted] 11 years ago
"Has anyone used a Canon ST-E2 with MORE than one strobe? Do you get full ETTL functionality on both strobes?"

Yes and yes...


choffee 11 years ago
Some more info on how the Canon ETTL stuff works can be found here just for future reference:


Sound like it does a pre flash, measures the light, then sends a signal using more flashes to fire the flash at the correct exposure.
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