Using camera flash sync output

@nicolas Does the camera have any kind of remote release? If it does, change your operation to use that as your shutter release and tie the date imprint signal into that. That is just a simple switch with no issues re timing etc involved in the Synch outlet.

Hello @zander, thanks for taking the time 🙂

Unfortunately It's an old camera, a Bessa R3a, I can screw a soft release cable on it, but it's mechanical, not electronical 🙁

@nicolas There are still a couple ways though. The first is to use that mechanical release but add a micro switch under the handle to trigger the date. Another approach is to use a sound activated switch you can make with an arduino or esp32 or esp8266.

@zander 

switch you can make with an arduino or esp32 or esp8266

I've already been able to make it work with an esp8266 with a code like this :

int inputPin = D3;  // Sync flash connected to camera
int outputPin = D4;  // Date back module

void setup() {
  pinMode(outputPin, OUTPUT);  
  pinMode(inputPin, INPUT_PULLUP); 
}

void loop() {
  if(digitalRead(inputPin) == LOW) { // Low is when the circuit is closed (aka when a photo is taken)
    digitalWrite(outputPin, HIGH);
    delay(100);
    digitalWrite(outputPin, LOW);
  } else{
    digitalWrite(outputPin, LOW);
  }
}

But I'll have to power the board so I'll need batteries, and maybe a switch on/off too ? I have now idea how much the board will consume, but I'm afraid it'll make my project too big and cumbersome...

So I looked into PIC microcontroller, they are smaller and I guess they demand less energy ? but I've never used one, do you think it could be a good idea ?

to use that mechanical release but add a micro switch under the handle to trigger the date

Yes, the mechanical solution is definitely my plan B , do you have a "micro switch" in mind ?

Thanks 😀 

@nicolas Remember esp8266 come as small as a large postage stamp and if you use deep_sleep after each shutter press it will only need one or two coin batteries. Sorry I don't know anything about PIC. No micro switch in mind, all you need is anything to complete a circuit from ground to switch to pin. even 2 small pieces of brass shim stock cut to size would work.

@nicolas 

Just extend your yellow wires and run them up the length of the cable and hot glue the bare ends of them onto the thumb rest and the limit plate at the bottom. Hot glue is a non-conducting medium so that should insulate them from being triggered by the metal rod and plate. All you need to do is make sure that the bare  wires touch each other when your thumb presses down the plunger button.

That way you can still trigger the date burner with the same method of connecting the two yellow wires.

@zander Hello !

You are right, I realized esp8266 are pretty small and battery can be pretty small too :

Plus I guess I can power both the date module and the esp8266 with the same battery 🙂

I've also been able to simplify my code and to enable deep sleep, so it starts to look like a good solution 😀

My code for anyone finding this post in the future :

int outputPin = D6; // Date back module

void setup() {
  pinMode(outputPin, OUTPUT);
  digitalWrite(outputPin, HIGH);
  delay(100);
  digitalWrite(outputPin, LOW);
  ESP.deepSleep(0, RF_DISABLED);
}

void loop() {

}

@Will Thanks for your suggestion I keep that in mind 🙂

@nicolas Good work. Have you seen how small an ESP-01 is?

Hello,

I'm back to share some updates, I've made a first prototype, and it's working.

I'm using a battery to power both the esp32 and the date module.

I need to think of a way to move all the electronics in a compact 3d printed box.