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Digital slave flash trigger

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This unique circuit has been tried with all three of my cameras and two others and works perfectly. It ignores all pre-flashes and only triggers on the last (main) flash.
No adjustments are needed. It will be tested with more cameras as they become available.
The current drawn is just 2.2mA at 3v. (about 4.2mA at 6v)The AA batteries were only used for making and testing the prototype. The finished unit will use a coin cell. The unit will handle trigger voltages up to 400v. Which I think will handle most commercial strobe units.
The range with 3v is about 25', I am going to work on that. That was much better when I used a 6v battery. There is now a ON / OFF sw. But the blinking LED (shown only in the picture) has been removed, drew to much current.
The hot-shoe was from an old camera I got in a junk store for $ 1.00.




This design is now outdated because of this: http://www.pbase.com/sinoline/pic_slave_flash
 
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#5
Wow, what a moron?

Anyway Rolf, how did you get your project to work from 3V when the datasheet for the NE556 specifies a minimum of 4.5V?

That 3V battery wouldn't last long?

Or did you use a CMOS timer like the 7556 or TS556?
 
Thread starter #6
Hero999 said:
Wow, what a moron?

Anyway Rolf, how did you get your project to work from 3V when the datasheet for the NE556 specifies a minimum of 4.5V?

That 3V battery wouldn't last long?

Or did you use a CMOS timer like the 7556 or TS556?
The sensitivity was much better with 6v. When I am experimenting I don't even think about data sheets. Mine is marked NE556N the 4011 is unmarked.

Took the LED out (it was ok when using 4xaaa's for power) and the circuit now draws 2.2mA. The button battery is 180mAH so there is plenty of longevity if you can remember to turn it off.
 

audioguru

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#7
Rolf said:
When I am experimenting I don't even think about data sheets.
There are reasons that manufacturers spec an absolute minimum supply voltage of 4.5V for a 555 and 556 IC. You might be lucky to find one that works with only 3V. Does it still work when the battery discharges to 2.999V?
If you make another one then I bet it won't work with only 3V.
 
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audioguru said:
There are reasons that manufacturers spec an absolute minimum supply voltage of 4.5V for a 555 and 556 IC. You might be lucky to find one that works with only 3V. Does it still work when the battery discharges to 2.999V?
If you make another one then I bet it won't work with only 3V.
How much are you willing to bet?
The one pictured in my original post is actually the second unit I buildt.
If you are so interested to prove me wrong, buid one for yourself. I have put this project on the shelf and are not going to resorect it, just to prove a point. I have now built and use Povel Janko's PIC design (jankop@volny.cz) which made mine obsolete.
 
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