Here’s an interesting one. This is an I/O expansion board for the Pi that comes with a case specially designed to be used with the card attached to the Pi.
From the manufacturer:
The I/O card adds the following functionality to your Raspberry Pi computer:
- Very high accuracy real-time clock based on the PCF2129A with CR2032 backup battery
- 8 quasi bidirectional I/O lines (PCF8574) 5V levels.
- 8 12-bit ADC inputs (MAX11614EEE+), 0 – 4.096V range.
- 16 8-bit resolution PWM channels (PCA9635), 5V levels @97 KHz with LED drive capability (10mA source, 25mA sink).
- Polyfuse on the 5V line to prevent excess current damaging the Raspberry Pi computer.
- Compact footprint due to the use of SMD components.
The card and case come in at an intimidating £53 on eBay or 45 euros (ish) on their site.
It’s a pity this is so expensive because it’s not altogether clear to the hobbyist what you can do with it. I’d love to get my hands on one and put it through it’s paces. Some demo programs are supplied, which is a great idea, but there’s not a great indication of exactly what it does for £50. I think hobbyists would lap it up if it does a decent amount of things!