I’ve now completed two versions of the envisaged USB visual meter and alarm sounder device, both based on the ATmega88P MCU and as envisaged in my previous post. A photo of the smaller version is shown, right.
I have published the design files and firmware as free open source (GLP v3) at Google Code.
Below is an image of the same board, with the first 5 of 8 LEDs lit up.
The original version of the gMeter board is larger (at about 150% the size of the MLF version) and uses an easier-to-hand-solder (bigger) ATmega88P microcontroller chip. It also includes a 4-pin header to connect a commonly available Bluetooth module (currently not supported in any way by the published firmware) as well as four spare I/O pads for expanded use, should the user wish to wrangle with the firmware source code, to that end.