#Arduino flash trigger v1 – parts list and schematics

So as promised here is the parts list for the first version of the Arduino flash trigger.

• 1x Atmega 168 or smaller chip with Arduino bootloader preprogrammed (the code compiled is only 4k)
• 1x 28-pin IC socket (so that you can use chip for other projects latter)
• 1x 16MhZ ceramic resonator
• 1x 16×2 lcd display, HD44780 compatible
• 1x 7805 5V voltage regulator
• 4x micro buttons
• 1x SFH615 optocouppler
• 2x 3mm led diodes (green for power and yellow for activity)
• 4x 220R resistors, 1x 10K resistor and 1x 1K resistor
• 2x trim potentiometers (4K7 and 10K)
• 3x male headers(6-pin, 3-pin and 2-pin)
• 3x ceramic capacitators(0.1 uF, 1uF, 10uF)
• 1x 3.5 mm female jack for connection to laser

Now this post wouldn’t be complete without Eagle schematic and board files. You can download them on the following link: Trigger schematics (396).

I don’t have schematics of the laser side because it’s simple. I’m leading 3 wires with 3.5mm audio cable, analog in, gnd and vcc(+5V). In the laser box I have laser which is connected directly to the vcc and gnd, one foto resistor that is giving to high value to analog in so I have one resistor before it connected to gnd.

So we have:

• GND wire is connected to laser gnd wire and to one side of let’s say 2M resistor which other side is connected to one leg of photo resistor
• VCC wire is connected to laser vcc wire
• Analog in wire connected to other leg of the photo resistor

It depends on which photo resistor you are using how big resistor value before it you have to use. Arduino is capable of reading analog in until value of 1024 and that’s reason why the big resistor value is needed, so you are testing which one do you need until the value of direct laser beam to the photo resistor is under 1024, mine is about 920.