Actually the first ‘project’ I ever did with a Raspberry Pi was sending a push message to my Iphone. It was 2012, I was lying sick in bed and found a new app on my Iphone called Pushover (what else to do when you’re sick?). With Pushover you can send and receive custom made push messages. On the website I found a simple Python script to send messages. I knew the Rpi was able to run Python code, so here my Rpi adventures started. Within 30 minutes I was able to receive ‘hello world’ on my phone (needless to say I wasn’t lying in bed anymore). Seeing ‘hello world’ on your screen is like the software equivalent of the blinking led, THE coolest feature ever!
I decided to hook up this push message feature with my doorbell. The idea is that every time somebody rings the doorbell, I get a push message that there is somebody at the door. The doorbell was already connected to a wireless transmitter and I wanted to keep that functionality. I used a relay to combine the transmitter with a switch on the GPIO header of the Raspberry Pi.
The led and 330R resistor can be installed in the actual doorbell, so the person can find the doorbell and is triggered when the bell is pressed (the led turns off when the doorbell is pressed). The 100u capacitor and flyback diode are to limit voltage peaks when using the relay. The ‘test’ switch is available close to the GPIO header to test the (software) functionality of the doorbell alert. The relay and test switch are connected to pin11 (GPIO0) of the Rpi.
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