This is a great way to get started with Electric Imp, and actually just a great little environmental sensor too if you need one of those. It’s really intended for people averse to soldering and breadboards - there’s no breadboard pins like an April.
Power is via USB (5v max) or 3xAA cells. You can get down to about 50uA with the imp sleeping (waking up on RTC) with all the sensors shut down, so you can get years of battery life.
It’s got a temperature & humidity sensor, an air pressure sensor, and a 3-axis accelerometer. It can wake from these too, if needed. For output, there’s a single WS2812 RGB LED, plus pads to daisychain more if needed.
Lastly, it’s got 4 grove headers: 2x I2C headers (3.3v power) and 2x generic IO headers (3.3v switched power); there are various nice things that can sit on I2C (eg displays) and the generic headers have one I/O each, which can be analog or digital and can be used to add buttons or relays etc.
Amazon are very easy to deal with. It’d be more expensive if it was sold via adafruit/sparkfun (they generally double the buy price to get to the selling price).
Other options will be coming… eg breakouts are on Digkey & Mouser who can ship almost anywhere.
No, this isn’t built in; the challenge here was in getting the maximum amount of functionality out of the imp001’s limited I/O (6 pins only!)
The best way to do this in a retrofit fashion would be to put a 47k resistor between J7 pin 2 (next to the 2812 LED, labeled VIN) and J4 pin 1 (left hand “grove analog/digital” connector), and then another 47k resistor between J4 pin 1 and GND.
Then, when configured as an ADC, hardware.pin2 will show half the battery voltage on it when pin1 is driven high (ie peripherals are powered up). There will be no drain when the imp as asleep.