The Pressure-Sensor Pads and Synchronising Everything with MaxMSP.
January 24, 2012 § Leave a comment
In order to test everything together, we had to buy the pressure sensor pads that we intended to use. We knew exactly what size they needed to be and after a fair amount of research into local stockists of them, we found the best place to get them would be Maplins in town. We ordered them online and it came to around £40:
Tom had already imported the audio and visuals into the Max patch and we knew roughly how we intended to correspond each pad with the audiovisuals, but we needed to attach the pads to the base and each pad to the arduino board before we could test this.
These are the pads once we had stuck them to the base; they had to be slightly overlapped for them to fit on. We hoped this would not effect how they worked but knew that if it didn’t we could un-attatch the pads and stoppers and re-do them:
We ensured that the wires were accessible and in the correct order before we connected them to the arduino and stuck them down:
We then attached the wiring together and stuck it down, syncing the wires with the correct holes in the arduino board:
We then tested the pads with the Max patch with our hands and then with the log to see if they trigger successfully, which fortunately they did. However, the overlapping and sensitivity of the pads did mean there was a fair amount of double triggering. We thought we could combat this by trying to find a way to crossfade between our set volume levels and visuals, as this would make the double triggering much less noticeable and smoothen the transition between the two ends of the ‘instrument’, but we had little luck finding a way to do so. So we settled on it the way it was and decided to refine it in the coming weeks, most probably taking the wiring and stoppers apart and removing the pads to re-attach everything in the most effective way. This is a video of some of the testing we did of the pads:
For the top sheet which we would use to hide the pads, we decided against our initial idea of staining a white sheet with mud/foliage, as Tom found a couple of sheets which fitted our base and suited chosen aesthetic perfectly: Their design was similar to the bark of a silver birch, so this was ideal for use in hiding the mats:
To attach this top sheet, we decided against our original plans of taking up the stoppers and re-attaching over the sheet or cutting holes in the sheet to fit the stoppers. Instead we decided that because we would be un-attaching it to re-work the wiring, pads and stoppers, our best method of attaching it would be to fold the ends of the sheets to fit inside the stoppers, plus it taught, tuck it underneath and staple it in along the inside edge, ensuring we do to staple to wires. This would also act to protect the wire connections and arduino, thus stopping any potential faulty triggering. This is the base with the sheet attached and the underside view of that attachment:
Overall our tests were fairly successful, there were a few issues when we had finished (overlapping pads, weak wire connection to arduino, no crossfade between changing audiovisuals, etc) but we felt these could be ironed out and the ‘instrument’ could be refined in the next few weeks as the project moves forward. We have a working prototype with audiovisuals for the crit, so we’re happy with the current progress of the piece.