Doorbell Combo Lock Can Open Your Garage Door

August 2, 2010 by Mike Szczys 24 Comments

Sometimes I get enough away from writing about other people’s accomplishments long enough to actually do my own hacks. Most recently I developed a combination lock that opens the garage door. The idea isn’t original, it is based on [Alan Parekh’s] button code project, but I did develop my own hardware and software. A four digit code is entered by pressing the button a number of times for the first digit, and waiting for a flash of an LED inside before moving on to the next digit. If the correct code is entered the door opens.

My version centers around an ATtiny13. I originally downloaded [Alan’s] code in hopes that I could port the PIC firmware over pretty easily. Unfortunately it was written in BASIC so I just took what I knew about the interface and wrote my own program. I developed on an ATmega168 so that I would have no trouble running out of programming space, and was able to optimize my code down to 964 bytes to fit on the tiny13.

The hardware is quite simple. I purchased a lighted doorbell from Home Depot and swapped out the light bulb for an LED. I choose this because the doorbell mounts in a 5/8″ hole in the trim of the garage door and is easily overlooked. I’m quite happy with the results, and if you want to play around with the idea, you can easily build the circuit on a breadboard and use another LED for the load rather than including a relay. Hit the link at the top of this post for the schematic, code, and build images.

Lunkenheimer Steam Whistle, Doorbell

May 16, 2010 by Jakob Griffith 30 Comments

We’re going to straight out agree with [Pete] on how surprisingly quiet doorbells are now a days, and if we had it our way we would put his Lunkenheimer train whistle doorbell in every home*. The setup he uses is surprisingly simple, opting for a pre-built wireless doorbell that signals a microcontroller which in turn drives a relay and solenoid. While he does include a video, we felt it didn’t quite show the intensity of these whistles.

*HaD is not responsible for hearing loss and subsequent melted brains.

Antique Phone Doorbell

May 13, 2009 by Caleb Kraft 30 Comments

doorbell

[Bryan] sent in this cool doorbell he made out of an antique phone. After seeing similar phones for $150 to $399, he picked one up on ebay for $10. After some cleaning and polishing, it was looking fantastic, but fairly useless. At this point, he broke it open and started hacking to turn it into a wireless doorbell. He picked up a cheap wireless doorbell and proceeded to gut it. The transmitter side got an aesthetic overhaul, a big fancy button and nice LED in a 50’s style were added. The receiver side got hacked up as well. It was incapable of pushing the required voltage to ring the phone’s bell, so he had to do some searching for a better circuit. Since his knowledge of electronics was limited, he was looking for something that could be plugged in and work without much modification. Eventually, he found the Silvercom AG1170-s5. At $7, he swiped it up quick. It may be a bit of overkill, but he’s using an arduino to trigger the whole thing when it receives the signal. You can download the Arduino sketch on the site.