TP: Cheap secondary wireless flash?

I haven't had any failures in the optical flash circuit, unless the camera was trying to do HSS in wireless. I didn't account for this, as I wasn't sure how to!

I have an older circuit with a description of how it works earlier in this thread. Here's the latest version I'm using:



Description:
S1 = On/Off switch
V1 = A 9-volt battery, should be enough for U1.
U1 = 5-volt Voltage regulator, we need to keep constant reference voltage for timing circuits.
C1 = Smoothing capacitor for U1, value can be approximate.
Vcc = Logic high voltage, 5V in this case, just to make it clear.
R1, LED1 = LED to tell if the thing is on. A 5k resistor give dim light, enough to tell if its on and not suck battery power; would depend on your LED too (I picked up one lying around).
Q1 = IR Phototransistor, activates when it detects light. I actually have two of these in my final circuit (in parallel) to improve sensitivity.
R2 = Sets a maximum amount of current going through the phototransistor (the ones I used were 50mA max).
C3, R3 = 10 hz High pass filter; this makes only rapid changes in light to activate the circuit (C3 and R1 are approximate).
Q2 = An npn transistor to bring the state of the NOR gate input low, which occurs during the lighting event.
R4 = Current limit resistor (can be anything over 10 ohms, really).
JK flip flop + OR and NOR gates = Logic system.
C7, R5 = Capacitor that creates the first pulse delay, combined with R5 to create ~160 ms. I use a 250k potentiometer for R5 so I can tweak it, it should be somewhere between 160k and 180k. The capacitor charges from the flip-flop, which can provide the current.
Q3 = NMOS that discharges C7 when it needs to be off.
R4 = Limits current going through Q3 (value is approximate).
R6, C8, R4, Q4 = A charge and discharge circuit to reset flip-flop #1 (similar to the other delay circuit). This causes the system to reset itself after about a second (i.e. if the system detects a stray preflash and there is no main flash event).
Q5 = P-enhancement MOSFET that triggers SCR1 when the ending flash event is detected.
R7, R8 = Resistors to provide the correct voltage to the thyristor gate (computed from gate triggering voltage and Q5's on state resistance).
SCR1 = Silicon controlled rectifier (or thyristor), which will create an electrical path on the flash unit, firing the flash. You can connect more of these in parallel if there are multiple flashes to fire.

Parts that I bought from mouser:
Voltage Regulator (U1): TL780-05KCSE3
Trim pot (R5): PTC10LV10-00643-PTC10LV10-254A202
Phototransistor (Q1): OP599A
NPN transistor (Q2): 2n2222A
NOR gate: CD74HC02E
OR Gate: M74HC32B1R
JK flip flop: SN74HC109N
PMOS (Q5): VP2106N3-G
NMOS (Q3, Q4): VN2222LL-G
SCR (SCR1): TYN408RG

Well, I've finally finished my WL flash trigger. Unfortunately it takes too much time for me to build one of these, and I don't think I have time to make this a product (I'm a busy student!). My current one kind of has some loose connections occasionally and doesn't work, a PCB is really needed for this. But at least it is possible, and the schematic is out there.

In these photos I'm firing my Vivitar with my Sigma EF-500 Super. I put the circuit in a mint tin, though it didn't fit perfectly (I underestimated the thickness of the wires on the bottom of the board.

Has anyone found the connectors that fit into the port on the side of the 56/5600 flashes? If we could find this, we could splice in a PC sync and use the digital peanut for the Min/Sony flashes. With the device the chych has designed, and some of these connectors to splice to pc cords, we could have a lot of flexibility in our set-ups and flash uses.

edit:Need to learn to preview my post first to check for proper punctuation!

Edited by sooten - 26 April 2007 at 17:35

I guess that the C/N systems are very similar. I base this guess on the fact that the preflash from popup (not wl) are the same as Minolta because the Wein PND optical sensoes work with these as well.

My son in law has a D70 with a SB800 that if I had a copy of your controller I could certainly test it. There are several Canon users in my church who I feel would love to let me try their setups.

I am assuming the hotshoe you are referring to you want to put onto the box with the controller in it? Maybe consider simply a pc sync connection that plugs into any number of light stand mounted oem hot feet with sync connector. You should also think about a   1/4 audio type connector that could plug into a mono light like the radio recievers that are available on ebay.

Does that make sense?

Aaron

chych if I can assist you in any way please let me know. Assuming this can work for K/M or Sony, the Canon guys have just as bad a problem. Marketing is my forte', build it and I will make it known.

Aaron

almorey@bellsouth.net

Edited by georgiaboy - 25 April 2007 at 06:23

So, chych, are you going to start manufacturing these things for your fellow Dyxumers that are less electrical circuit capable than you are? This seems to be a definite need for us.

If you can build these or have these built, and ph0t0man gets his lens rental business going, we would be in great shape!