For me, an ideal strobist flash would be an extremely cheap manual flash that you can control remotely. Extremely cheap and remote control?! I am surely asking too much! But why is that too much to ask? It doesn't even have to be RF control - it can be IR. All that the manufacturer has to do is to add a IR demodulator chip (probably something like $0.1 when bought in large quantities) and make a slight firmware change to the flash uC (almost free). The Chinese IR remotes are something like $2-$3 so they could sell a remote-control-enabled flash basically without raising the price! When in 2010 someone like David Hobby, who is very passionate about the use of a manual flash and who can probably afford any flash he likes, has to walk a few meters and lower the light stand just to change the flash power.... and the cheap remote technology has been around for more than 20 years... it certainly seems like a huge missed opportunity.
To prove the point I have set out to build a cheap IR remote for my YN460 flash. Here is the result:
http://www.youtube.com/watch?v=2osloXHi6eE
And here is my circuit diagram:
As you can see, the circuit is extremely simple. It's based on the excellent picaxe micro-controller. Now, before you freak out that that is way over your head, know that I knew nothing about micro-controllers before starting this project. The picaxe is really simple to work with as it was basically designed for kids to use
The manuals are excellently written with people that know next to nothing about electronics in mind.Actually, the only part of the circuit that is YN460-specific is the solder points on the flash. If you have some other flash that also uses a two buttons to set the flash power level than it's more than likely that you can use this same circuit to remote control it. Solder points 1 and 2 are the positive side of the said buttons and the point 3 is the negative side. The circuit simply simulates the pressing of a button (any button you connect it to).
The parts for the whole project shouldn't cost you more than about $10-$20.
All the parts can be ordered from the TechSupplies:
Transistor: 3X http://www.techsupplies.co.uk/epages...roducts/TRT001
Picaxe: 1X http://www.techsupplies.co.uk/epages...oducts/AXE007M
Holder: 1X (8pin) http://www.techsupplies.co.uk/epages...roducts/ICH008
IR sensor: 1X http://www.techsupplies.co.uk/epages...roducts/LED020
Capacitor: 1X (4u7) http://www.techsupplies.co.uk/epages...roducts/CAP004
LED: 1X http://www.techsupplies.co.uk/epages...roducts/LED033
Resistors:
1X (10k 100pc) http://www.techsupplies.co.uk/epages...lectSubProduct
1X (33k 100pc) http://www.techsupplies.co.uk/epages...lectSubProduct
1X (470R 100pc) http://www.techsupplies.co.uk/epages...lectSubProduct
These parts are not exactly the same as the ones I used but they should be compatible. The IR receiver TSOP1138 that I used is a bit too large (though it's probably a bit more sensitive). The one linked above should work just fine.
You'll also need some way to download the program to the picaxe. How to do this can be found in the picaxe manual 1: http://www.picaxeforum.co.uk …sheets/picaxe_manual1.pdf
Basically what you will need is another 20k resistor, either USB or serial picaxe download cable, a 3.5mm stereo connector and a breadboard though you could probably get away with only a DIY cable (if you have a serial port).
The trick is to try to solder the circuit to be as small as possible because there is not much room inside the flash so I don't recommend the PCB approach but a 'dead-bug' soldering style that I have used. Don't know about the YN460-II (it's got a slave detector in front) but on the YN460 you can get significantly more space if you make a large rectangular hole below a fake IR window.
Here you can download the BASIC program (firmware) for the picaxe:
http://domjan.fizika.org/flash_remote-08M.bas
If you have and problems with picaxe programming (after you have read the excellent manuals), this is a great place to ask for help:
http://www.picaxeforum.co.uk/forumdisplay.php?f=2
The receiver will respond only to the Sony TV remote (or any universal remote set to Sony mode). This is a picaxe limitation and can not easily be changed.
Some inexpensive remote recommendations:
http://www.dealextreme.com/details.dx/sku.2684
- shown in the videohttp://www.dealextreme.com/details.dx/sku.2663
- this is the one I am currently using, though they have sent me a white version I so had to tape it with a black sticky tape so it would match my RF flash trigger. The IR remote's size is conveniently the same as the RF trigger's so I have it permanently mounted on top of it:
A few notes on the firmware usage:
One of the problems I have tried to solve is the circuit power consumption. As there is no separate power switch for the circuit, it's connected all the time to the flash batteries and will drain them eventually. It minimise this power drain I have made it possible to completely cut off the power to the IR demodulator and also put the picaxe in a low power state.
To reset the receiver to it's initial (standby) condition, open and close the battery cover. The LED should start blinking. You have 5 minutes to send any IR code to the flash (doesn't even have to be Sony TV code). If no signal is received in 5 minutes, the receiver will shut off at which point you would have to again open the battery cover if you want to use it.
Once the first code is received, the receiver switches to 'ON' mode in which it continually scans for the Sony IR remote codes. It understands these codes:
Vol + increase power by one stop
Vol - decrease power by one stop
Mute turn the LED off for 5 seconds (useful for programing some universal remotes)
Power put the receiver in the OFF state
1-7 directly set the flash power level
When a valid code is received the LED momentarily turns off and on again to indicate that the action has been taken.
The range I am getting is quite good - about 15-20m direct line of sight. In a typical room with a white walls no line of sight is required - a bounce from a wall works just fine.
It should be extremely easy to modify the picaxe program to use a different set of keys so you can control two sets of modified flashlights with the same mini IR remote (one set would use ch+/ch- keys).
If you've got any questions, feel free to ask either in this thread or on the picaxe forum.
