Marvellous Milk

This project was for Sport Relief 2014, in association with We Make Stuff Happen for Cravendale Milk.

The idea was to gather a team of friends, get on an exercise bicycle, and see how much milkshake you could mix by pedalling as hard as you could for a minute. We had a display screen with a speedometer that averaged the team’s speed, so they could see how fast they were going, and at the end of the minute, it would total up the amount of milk produced by filling a cylinder on the screen. While they pedalled, a giant “milkshake mixer” would run, churning “milkshake” in front of them.

We did this by hooking the exercise bicycles to Arduinos, which counted the number of revolutions made by the bicycles’ wheels while being pedalled. This information was fed to a server which kept track of the race progress, handled the display, and also managed the teams. We also had an Android app installed on four tablets, to take down team details and to trigger the races when people were ready, via a “remote control”-type screen.

My job in all this was to write the server software and the Android apps. The software was installed on a laptop at the location, which was hooked to a wifi router, allowing the tablets to communicate with the servers.

The biggest problem we had during the process was, ironically, entirely hardware-related: our initial laptop choices were second-hand Lenovo Thinkpads, a couple of years old but both powerful and robust. Sadly, these only had VGA display connectors and our screens only had DVI. We spent some time trying to get things working through adapters, but in the end we had to purchase two emergency backup laptops: cue a late evening trip to PC World for the most suitable candidates, which most certainly were not Thinkpads. I then spent three hours struggling to get Windows 8 up and running well enough to run my server software before giving up, breaking the BIOS security, and installing Linux. An hour later, we were good to go!

There were three separate installations on consecutive days: the first day, we set up at the Cravendale offices in Leeds, without the mixer; the next day we were at Sainsburys’ head office on Holborn, in London, with the mixer; and finally, we set up in an inflatable tent at the Olympic village for the actual Sport Relief day, bringing the two previous installations together so the public could have a go.

All in all, it was a great deal of fun, some interesting challenges, coupled with a couple of windy days in a unit in North Walsham, pedalling like a maniac to test how the software was working!