Doorbell modifications


I am venturing into the world of arduino. It's exciting and reminds me of high school electronics class, though I've forgotten much of that after over 20 years.

I thought of a useful safety project. First a little background abut why.
I have a nice doorbell in my home, the mechanical kind with large tubular "chimes" and electric coil and piston type strikers (I think there is a special name for these guys, but I've forgotten).

A while back, when on vacation, upon return the doorbell want working, and it turns out the button had become stuck in the on position. As it turns out, this is dangerous, as the repetitive activation of the electromechanical striker device can result in a fire. Indeed there was perhaps some smoke generated and a trace of a mark on the wall near the bell. I ended up replacing the unit and button. The potential for another stuck button remains however.

I'm a pretty terrible programmer, but here are some thoughts about a sketch. It would need to limit the frequency that the bell will ring, and will monitor the existing button. It would also detect if the beer is stuck, as opposed to being just repetitively pressed by a prankster for instance. It might also have a sleep mode to prevent being waken in the night by a bell ringer. Using the BOUNCE function with some modification might be the answer, and perhaps also adding code to limit how frequently the bell will ring, deactivating it during the nighttime hours, so it would need to have a time-keeping ability possibly. This isn't strictly essential however.

In addition, I have recently added a basement storage room and it's not directly connected to the house, such that I cannot hear the bell if I am in the basement. It would be convenient to add a repeater that signals a secondary unit in the basement to make a noise. This wouldn't need to be very fancy at all. The best way in my opinion to accomplish the secondary "bell" or buzzer I think would be using wifi. This would eliminate any wiring sticking out of the bell enclosure in the Main house, and would be wife-approved. Also, there is no direct way to get any wires into the basement, though with some difficulty, I have connected an old wifi router down there connected to my network by hard wire, acting as a wireless access point.

Last issue will be powering everything. The doorbell operates on AC, the voltage I think is 24 via a transformer near the breaker box. I'd probably need a way to make a AC-DC power supply to run the arduino and any connected equipment. Ideally this would all fit behind the molded faux wood doorbell housing.

I would sincerely appreciate any and all advice on the feasibility of doing this with an arduino (or some other option if arduino would be overly complicated to achieve the plan), as well as any suggestions, help, advice on how to write the sketch.



Definitely feasible but possibly more work than you are imagining. Getting a new non-sticky button will be easier.

I'm thinking of just a simple relay to isolate the bell from the button when it's to be silenced. The Arduino is not isolated (but it is protected from 24V or higher) so it can count the button pushes, maybe send you an email to let you know how many times the 3am pranksters pushed the button.

Start with an Arduino Uno and a relay shield. Get it working on the bench. Get your power supply and protection sorted out before attaching it to the real bell. Ultimately you will end up using one of the smaller Arduinos such as the Pro Mini. (The Micro is my favourite right now.) Work out what you want it to do - can the Arduino ring the bell itself? Stuck-button mode might be a short 'ding' every 5 minutes or something. Write the sketch which does all this.

The bell enclosure has wires going into it. So why is it a problem for other wires to come out? I'd run a wire inside the wall down to the basement instead of relying on wireless.