Blynk controls Canon T2i remote shooting

Hi Blynkers : I just started playing with Blynk this weekend.
After leaning on how to use button widget to turn on/off LED, I applied the same concept to remote shooting on my Canon EOS Rebel T2i (EOS 550D.

My hobby is to take pictures of Hummingbirds around my feeder.

Items used are the followings:

  • Canon camera with remote shooting cable. ( I DIY this cable )
  • ESP8266
  • PC817 OptoIsolator, single channel
  • Respberry Pi 3 B+ running Blynk Local Server

Blynk UI screen is very simple screen containing button and Label.

Blynk :

The input is stored in Virtual pin V1, button is set to PUSH, ie. mimicking temporary switch.
V2 indicates the state of the camera either on or off.

ESP8266 sketch:

The V1 value recieved and process according to the value, 1 = shutter on, 0 = shutter off.

From ESP pin D8, it will turn on the phototransistor on the low voltage side. This results in circuit close on the Collector-emitter side. When the connection between shutter and common strips on the remote cable is established,the exposure commences.


int pinData = param.asInt();

if (pinData == 1) {
digitalWrite( led, HIGH);
Blynk.virtualWrite( V2, 1);
else {
digitalWrite( led, LOW);
Blynk.virtualWrite( V2, 0 );

void setup()
pinMode( D8, OUTPUT);
Blynk.begin(auth, ssid, pass, IPAddress( 192,168,1,115),8080);

void loop()