Hardware Hacks

Making a doorbell semi-smart

If you’re anything like me then you sometimes miss the doorbell ringing. It may be because you’re engrossed in a movie and the doorbell sound doesn’t register. Or you might be (in these COVID times) in a make shift home-office with the door closed and an air-con blasting out. Or you may even be out of home. Can we add some home-automation smarts to a dumb doorbell? How does a doorbell work?

Digital Safe version 2

Previously I modified a cheap electric safe to work with an Arduino, because the original controller board had failed. But because my build skills aren’t the best, I kept getting serial port issues, and more than once needed to get to the emergency key to open the safe. At the same time someone asked me if the same design would work with one of the real cheap ($30) safes on Amazon.

Adding some smarts to a dumb aircon

I have a Friedrich aircon. It’s of the old school. The only intelligent part of it is “eco” mode (turn off the fan when the temperature is cold enough) and a simple timer (“turn on in 9 hours time”). It’s this timer that annoys me; you have to set it every day. A number of days I would go to work, forgetting to set it, and come home to a house in the mid-90F.

Extending automation to the garage

My garage door is controlled my a Lynx 455 Plus garage opener This is a pretty traditional opener; a door-bell type button inside the garage to open/close the door and a remote control for wireless access. I wanted to see if I could make this smart-enabled. Now the control side is simple enough; just put a relay in parallel to the button. If the relay closes then the opener will think the button has been pressed.

Emulating a Philips Hue light

Over the past couple of years I’ve been building out an Alexa skill for my media center. So now I can say things like “Alexa, tell media to play music”. That will turn my receiver on, switch it to the Mac input, and start iTunes playing. Similarly “Alexa, tell media to switch to TiVo”, “Alexa tell media to pause”. The backend code running on the Mac asks the receiver what input is selected (TiVo, Mac, BluRay…) and if on the Mac it works out what application has focus (iTunes, DVD Player, Kodi, …) so when a command such as “pause” is received then it knows how to send the appropriate action.

Software for my digital safe

A few weeks back I completed my Arduino hack for a digital safe. What was missing, however, was the software to drive it. One requirement I had was to let it work with password managers. I also had the idea that maybe remote access (e.g. control the safe while away from home, to grant a guest access) might be useful. This kinda meant it’d be easiest to do as a web site, with internet connections forwarded via the router.

Adapting a digital safe to be computer controlled

For a number of years I had one of these cheap electronic safes. They allow for a combination to be set. I bought this one from Harbor Freight in 2004: This post isn’t about that safe though. About 10 years later the safe started to stop working; the control panel stop responding, it made horrible noises… Fortunately anger lifting and dropping the safe got it working again to open the door.