This is a fun project I put together the other day while teaching myself more about the Makey Makeys and Raspberry Pis I got for my library’s maker events. It’s a good beginner project, and can be fun for makers of different ages. I’m currently using the doorbell for my office, which has been both fun and useful!
Raspberry Pi with necessary accessories (I used a Raspberry Pi 2):
Computer monitor or TV
Keyboard and mouse
Micro SD card
Speakers (optional depending on your monitor)
Pennies (or something else conductive)
Something to function as the doorbell’s button
- The first thing I did was construct the circuit using the Makey Makey. The kit comes with alligator clips you can use. One clip will need to be connected to Earth (ground), while the other can be connected to any of the other spots you want. I chose to set mine up to act as the space key. The other end of each alligator clip can be clamped around a penny.
- I mounted everything on the wall using tape, which in retrospect was not the best way of doing it, but I didn’t have anything better on hand at the moment. I set it up so that the pennies would be close, but not touching. I also added a Batman logo I drew with a 3D pen, just for fun, to act as the doorbell’s button. When the “button” is pushed, the pennies touch, closing the circuit and sending the computer (which in this case will be the Pi) a signal that the spacebar is being pressed.
- I have a touchscreen for my Raspberry Pi, so I ended up using that. If you don’t have one, you can set it up with a computer monitor, keyboard, and mouse; it doesn’t need to be anything fancy, but you do need something with HDMI support. A TV with HDMI support can work, as well. For the operating system, I installed NOOBS on the SD card, which let me install the Raspbian OS. This was ideal for me, as Raspbian comes packaged with the programming app Scratch. (Since I was using a touchscreen, I also installed Matchbox Keyboard.) Check out the links–they will lead you through the installations of each.
- With my Raspberry Pi all set up, I was able to build a quick program in Scratch to actually make the doorbell happen. Since the Makey Makey was sending a signal to the Pi that the spacebar was being pressed, my Scratch program is configured to play a sound as a result of this trigger. To get my doorbell sound, I simply downloaded a doorbell sound effect from Freesound.org and imported it into Scratch. Because of how easy this is, it would also be simple to replace the sound anytime I wanted a new one.
- The Raspberry Pi doesn’t have its own speakers, so I borrowed Emily’s old computer speakers so I could output sound. If you are using a computer monitor with built-in speakers or a TV with sound, you won’t need extra speakers. If using speakers, just a note here: you will need speakers that are separately powered, not ones that draw their power through USB. You might also need to make sure the Raspberry Pi is configured to play sound through the headphone jack (where the speakers plug in). If using HDMI, you can configure it to play sound that way instead.
Got questions? Successfully built one? Share in the comments below or on Twitter!