Developer Joshua Kennedy wanted to change the beeping sound that the refrigerator started to make when the door was left open for more than 60 seconds.
To get rid of the annoying sound without disassembling the refrigerator, he decided to use a control panel daughter board that provides access to the refrigerator's settings.
After discovering that the board had a serial interface, Kennedy connected it to a Raspberry Pi single-board computer and created a Python driver to control the lights and determine the state of the buttons. However, these experiments didn't result in the beeper going off, so Kennedy decided to create a modifying chip using a 555 timer chip. He used the timer to signal the refrigerator that the door had just closed after a 59-second delay. A full description of the project is available on Kennedy's blog.
After discovering that the board had a serial interface, Kennedy connected it to a Raspberry Pi single-board computer and created a Python driver to control the lights and determine the state of the buttons. However, these experiments didn't result in the beeper going off, so Kennedy decided to create a modifying chip using a 555 timer chip. He used the timer to signal the refrigerator that the door had just closed after a 59-second delay. A full description of the project is available on Kennedy's blog.