The Arduino, Doorbell project - Part 1 Hardware

The inspiration for this came whilst browsing the internet for general tech stuff, at which point I stubbled across a post on a postbox (the american type) that was hooked up to a microswitch and an arduino. The result of this was that the arduino could trigger notification events.

Whilst this was a nice idea and I appriciated the tech, its of no use to me as my post comes through the front door and dont really need to get to it, unless its to stop the dog eating it. However this did prompt some more research into this type of project which lead me to a number of posts around the internet which I will reference later, that involved hooking an Arduino up to a wireless doorbell.

Now this I have a use for!

a) If I am in the garden, upstairs, shower etc etc then I will get a notification through to my phone/ipad

b) The "bell" part will be removed, so there will be no audio apart from notification through my phone, which means the dog doesnt get wound up! He is not keen on visitors.

c) With some additional components it should be hard to hook a camera up to take a still image when doorbell rung and email it to me.

d) Possibly the same principal could be used using a PIR sensor as the trigger, creating a security device.

Now I already had an arduino, which was reserved from my sentry gun project but this can wait. So a quick trip to B&Q(Hardware store) I picked up a wireless doorbell for the grand total of £7.

Now time to start hacking, the main bell unit was swiftly taken to pieces, noting the 4.5v required to drive the bell unit, meaning it could be driven directly from the arduino's 5v output.



The internals of the main unit.




Using the arduino code from some of the guys elsewhere on the internet, it was possible to flash the arduino to register an analog input, then trigger the led for debugging purposes, and using the serial print output send a user defined text line to the serial monitor on pc.

After flashing the Arduino, for testing purposes I soldered an additional couple of wire coming off the speaker connections to connect to the arduino, this would enable me to hear the doorbell for debugging purposes.



Now power connected to the arduino board, speaker wire into the analog input and hit the button!

So, I have power and it lights the test led, now to see what happens with the serial monitor




Top left of my laptop is the serial monitor, showing "on" when it registers a doorbell push, there is a slight delay, this is due to the doorbell playing a tune, so the code on the arduino has a delay in it to avoid multiple notifications.

So this is currently where this project is sitting at the moment. The next step will be the software side, as my server is a windows based machine, I need to get a serial monitor program from somewhere, this will register the serial line, and then trigger a Growl notify command.

Growl server runs on my server all the time, and is set to send all notifications to my iphone and ipad using the Prowl app.