Chumby One was just announced on bunnie’s blog. You can get it now for 99$ pre-order price but once they start shipping the price will go up to 119$. You can read here about the story behing Chumby One and how bunnie tried to keep the price low by using every feature of this new processor from Freescale the i.MX233. It turns out the i.MX233 has 3 internal switching regulators and it uses only one inductor to do the job. Next to the switching regulators the i.MX233 has even more analog features integrated like : audio codec, speaker amplifier, USB PHY, video DAC, battery charger and more. This played out an important role in the final price of the Chumby One. You can read more about it on bunnie’s blog.
This device is a clever watchdog for your home, it monitors doors, water and temperature in the basement, the sensors have wireless interface so no need to trace cables, the main unit is connected to the phone line for remote access. It’s not just a simple alarm system, beside that it monitors the acces points, it also checks the temperature in the basement, to prevent in case of low temperatures the water in the pipes can freeze and crack the pipes.
The brain is the MC9S08GT micro controller from Freescale, so it is harder to replicate, but you can find usefull solutions in the documentation for your future projects, maybe redesign the entire system for your favorite ATMEL or PIC micro controller.
Everything is OK alarm:[PDF] – [Download]