For my own rover, Data Bus, I've been working on a board that converts Sharp range sensors to I2C.
I ran out of analog ports and had to prototype an I2C solution for my obstacle detection. I have this problem on all my robots. Pokey has too few analog ports. And I want to run a few of these on my RPi tele-rover.
They'll work with any Sharp ranger. For that matter, with any analog sensor (ideally at 3.3V or 5V). I plan to test a Maxbotix Sonar module soon.
Up to 27 of these on an I2C bus without re-programming the base address.
The firmware's oversampling, decimation and low pass filtering increases resolution and lowers noise floor. The analog anti-alias filter helps too. Performance is really good. Here's a pseudo-theremin demo:
They're running ATtiny44As. 6-pin AVRISP header doubles as I2C interface -- SPI and Serial on the newer revision is possible; I break out an ~SS pin. I also break out 2 GPIOs for the heck of it. I'm testing out SOIC and QFN versions.
If there's anyone who's building a project using analog rangers (Sonar, Sharp, other) and wants to try these let me know.
I have example code for Arduino, mbed, Raspberry Pi, and Propeller so far.