The internet doorbell - #EverydayEngineers

Giles Blake found that he couldn’t hear his doorbell when he was in his back garden.

He solved this problem by creating an internet-connected doorbell system for less than £30 using the newest member of the Raspberry Pi family – the Pi Zero.

Why did you decide to make this?

My wife and I were sat at the back of our house when a friend called me on my mobile phone asking if I was home as he was stood outside and had rung our doorbell a number of times. We haven't got a huge house but with the TV on and the door closed, we hadn't heard the doorbell going. This was what gave me the idea to create something that sent an alert to our smartphones when the doorbell rang.

How does it help you?

Well, we no longer leave people standing on the doorstep ringing the doorbell when we are at home. I also know when someone has tried to deliver something at home. Nothing earth-shattering, but useful to know!

How easy was it to make - did you come across any challenges

After a bit of research, I knew what I wanted to do and how I could do it. I needed a doorbell with a wireless receiver that usually ran off of two AA batteries so that I could actually run it directly off of one of the 3.3v pins on the Pi Zero. It also needed to have an LED on it that flashed when the doorbell was rung, this was so I had something that I could wire up to the Pi's GPIO pins and detect the change with.I'm self-taught with regard to electronics and not the world's best solderer but there wasn't that much to do to get this working. One problem I did come across was that it was initially prone to detecting power spikes, like the washing machine turning on, and registered them as false doorbell rings. After a bit more research I introduced a small capacitor into the circuit and intertwined the wires connecting the LED and the Pi together to reduce this effect.

How did you learn how to use your Raspberry Pi?

I bought my first Raspberry Pi, a B+, more out of a geeky curiosity than anything else, but I did already have a couple of home automation products in the house and took on the challenge of seeing what I could do with them. I found that Python was relatively easy to learn and there are lots of resources out there to help get a novice started. I now have five Raspberry Pis, including the Zero that's part of the Internet Connected Doorbell project. They are doing various things, controlling some smart lights and power sockets, collecting data from the heating system thermostat, running a webcam and also as part of a photo booth I created for a party. One thing I can definitely say is that they are addictive little bits of kit but in a really good way.

How much did all the parts cost?

Power supply and cable £5.00 (eBay), Doorbell £6.00 (eBay), Micro USB adapter £1.00 (eBay), USB WiFi Network Adapter £3.50 (eBay), 8GB microSD card £5.00 (Amazon), 0.1uF Capacitors £0.12 (eBay), Raspberry Pi Zero £4.20 (Pi Hut) - A Pi Zero is perfect for this. Small, powerful enough to do far more than I need for this application and so cheap! The only drawback currently is getting hold of one as the demand for them is huge. Raspberry Pi Zero case £3.00 (eBay) - This is optional but tidies the look of the whole thing up. Wires and solder - I had them in stock already but probably £0.20 worth. A grand total of less than £30.

What tips would you give to someone who is interested in making something with a Raspberry Pi?

Google is definitely your friend. If someone hasn't already had a go at doing what you are thinking of doing there will be something that is either very close or could be used as building blocks for what you want to do. eBay is also great for cheap electronic bits and pieces, as long as you are prepared to wait for a few weeks for them to arrive sometimes. Lastly, I've learned not to throw away anything that might have useful components within it before stripping them out first.

Here is the very simple Python script (doorbell.py) that runs the Internet Connected Doorbell. It uses an API for a free online application (Pushover) that allows you to push notifications to an app running on Android or iOS. http://qeprize.org/createthefu... doorbell script