Author Archives: Dav Stott

About Dav Stott

Dav Stott is a 30-something computer systems engineer. When he's not getting carried away learning some whizzy new technology, he's taking photos of the things he's cooked up in the kitchen, learning about the world of whisky or out hill walking. Occasionally he writes about it.

Salted caramel sauce

Caramel Sauce

Caramel Sauce


Making caramel is hard, but making a caramel sauce at home is surprisingly easy, taking three ingredients and just a matter of a few minutes, albeit a few minutes of paying close attention to the stove with a whisk.

I’ve got a few uses for caramel sauce and I wanted to write down my recipe so that Google can find it more easily for me next time.

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Raspberry Pi Ultrasound Sonar Range Sensing

SRF02 sensor. About the size of 20p.

SRF02 sensor. About the size of 20p.


I thought it would be fun if my robot could take measurements of its environment so that it can eventually create maps of its world. My budget won’t quite stretch to a spinning laser beam to create a LIDAR point cloud, so I’m starting out with a ultrasound sensor and an infrared sensor, connected to my Raspberry Pi using its I2C bus. This article explains how I set up the ultrasound sonar sensor.

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Digital cameras and memory card speeds

Digital cameras often have a rapid shoot mode, where they take still photographs as quickly as they can. I always thought that the maximum rate was limited by the camera’s internal hardware, but after reading Jeff Atwood’s comments on modern USB Flash drive performance, I wondered how significant the memory card’s speed is.

As it turns out, it matters a lot. A modern memory card totally transforms my camera’s performance, letting it shoot at full speed for as long as my finger rests on the trigger.

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