Newbie help - Flashing output on GPIO pin when button is pressed on app

Hello, i am restoring and upgrading a classic electric vehicle (Sinclair C5).

I have a got my Raspberry Pi Zero W hooked up to an 8ch relay board, so far the app on my iPhone works perfecty for controlling whether the relays are on or off.

However i would like 2 of the gpio outputs to flash for the indicators. Is it possible to do this and if so would anybody be able to help me with some simple step by step instructions?

I’ve attached an image to hopefully express my point clearer, when either button ‘Left Indicator’ or ‘Right Indicator’ is pressed i would like a send a flashing output.

Thank you in advance.


Study the LED_Blink example in sketch Builder and modify accordingly.

Hi thank you for the quick response.

I’ve been looking at it but where exactly do i put the script?

Are you more proficient in javascript or C++?

Neither, i’m a complete newbie when it comes to all this sorry.

As Sketch Builder is C++ take a look at this thread for C++ on the Pi Using C++ on a Raspberry Pi with Blynk

Thanks again for the reply, ive tried to put the LED blink script into main.cpp but nothing happens when i run ./blynk.

The led on the widget on my phone doesn’t blink.

Are you running Blynk with this syntax?

sudo ./blynk --token=xxxxxxxxxxxxx

Do you have WiringPi set up?

Did the compile go ok?

Did you keep the following vital parts of the orignal main.cpp?

#define BLYNK_PRINT stdout
 #include <BlynkApiWiringPi.h>
 #include <BlynkApiLinux.h>
#include <BlynkSocket.h>
#include <BlynkOptionsParser.h>

static BlynkTransportSocket _blynkTransport;
BlynkSocket Blynk(_blynkTransport);

#include <BlynkWidgets.h>