Past Work - Snake Pit 2
The original version of The Snake Pit was well received but the tracking system, based on a pressure sensitive floor, was problematic. The 8x4m mats were difficult to transport and store and adapting them for a different layout appeared almost impossible. On top of that, we had quite a lot of problems getting them to work properly because the pressure-sensitive material we used in the mats only resulted in small voltage changes that were sometimes masked by other phenomena, such as fluctuations in mains voltage.
As a result, I scrapped the mats after the Graduate Show at Plymouth College of Art (PCA) and Phil May, my software engineer collaborator on this project, developed a camera based tracking system. PCA wanted to show a single robot snake operating on its 3D Design Craft stand at the London Design Fair (LDF), on 20-23 September 2018, so we had an added incentive.
 | Here's what our cameras look like: A "Zero Cam Fish Eye", is connected to a Raspberry Pi Zero board fitted with a 16GB SanDisk memory card. It was surprisingly low cost - 4 sets of these items cost a total of £139.62. Each assembly is pretty small. The Raspberry board is 30x65mm. The bracket is made of plywood, threaded rod and plastic tube. The one pictured is designed to fit in a corner. | |||
 | Phil created a system that enables us to configure any setup with up to five snakes and four cameras. We only have one snake at the London Design Fair - pictured here in this mockup in Rhino. At one stage we thought we could get away with three cameras but after trials we realised four was necessary when there was more than one person being tracked. Even then, the cameras picked up quite a lot of false positives - shadows and reflections. We had to "tune" the cameras to discern other differences, such as colours. And we realised that the camera orientation needed to be calibrated quite accurately. | |||
 | In real life, the stand will be cluttered with plinths supporting exhibits. Luckily the plinths aren't solid so we've been able to put the cameras at the back of the stand at low level, clamped to the plinth legs. | |||
 | We've conducted trials of the set-up, with the plinths in place, at PCA. It worked!! Phew!! | |||
 | Here's the stand at the London Design Fair. The snake attracted a lot of interest and led to the PCA stand being nominated as one of the "Top Picks" of the show by Design Week - see this article. Installing the snake was stressful (lesson - come prepared for the unexpected) but the location of the stand was great - right next to a doorway which helped the snake grab people's attention. | |||