The fine folks over at Phenoptix have just started selling the SR-04 ultrasonic distance sensor for £1.99. It comes with a couple of resistors to protect your Pi. All they need now is some instructions on using it with your Pi, but that’s a fairly straightforward thing to do and, in fact, Raspberry Pi Spy did an excellent tutorial on it a while back. It’s a digital sensor with only a 3mm margin for error so you don’t need an analog-to-digital converter and it has a big range (bigger than the 2-5cm Phenoptix are advertising – I’ve had readings up to 3m, admittedly with a larger margin for error than 3mm).

There’s no excuse not to get one if you want to measure distance such as, for example, on a robot.

Take a look at their online shop now to get hold of one.

I have no connection to Phenoptix apart from having met the Founder (Ben) at the most recent CamJam and thinking that they’re a very good online retailer. Just sharing the good shopping news!