Onyx Ashanti – Finally sorting that pesky pressure sensor issue

December 8, 2011 Posted by onyx in Uncategorized

Finally sorting that pesky pressure sensor issue

The pressure sensor saga will soon be remedied! Yaaaay!!

When i did the first controller build, i needed a pressure sensor to register breath pressure and i didn't want to wait to have the proper one that i wanted at the time, the freescale mpx5010, to be shipped, so I went to the local electronics superstore here in Berlin, and purchased one that was close enough. the mpx5100DP. this was the wrong sensor in many ways. first, it was 5v instead of the 3.3v that the arduino fio uses. It had dual ports that i believed at the time were seperately addressable but came to discover that they worked together to provide a differential signal(pressure/vacuum balanced output) which was useless to me so i just used the pressure side. and, most significantly, to get the full data range from it required 14.5psi of pressure, which i discovered is about 10x more that most humans are capable of blowing. so the signal was very weak. because of this, i multiplied the signal A LOT so that i had a useable data range, but this made the data stream very "steppy" and very noisy, representing itself in my sounds as a glitchy/static-y-ness.

I didn't care for most of the year because it worked, but, i decided that it was time to do it right, now, so i went to Mouser.com and ordered 8 of these babies. the freescale MP3V5010GP. the "3v" stands for 3 volts, which puts it in the arduino fios goldilock-zone and the "GP" is for gauge port, which means it only has the single port and is much much smaller. as well, this baby has a 1.45psi pressure range which is SO exciting because now, rather than multiply the signal, I can divide it, which will mean a smooth as silk dynamic range of values. I just ordered them a little while ago and they should arrive in a few days. yaaaay!!

there are loads of parts to order and wait for, I will dedicate this week to making the software suite "playable", i.e., able to to take it over to Tacheles (my favorite busking spot) and perform with it with reasonable competency. the gap from not playable to playable is smaller than it was and i expect to be able to do a busking session by Saturday or Sunday of this week. if all goes well, the gap from playable to "giggable", i.e., the ability to rock out at a gig that i get paid for, hence, the need for "pro" sound is important. I have a show at Rote Salon on Dec 22nd and i plan to use the full software suite I’ve been working on for 3 months. if all goes well, the software will be within the 70-80% ready range at that point.

I will be using a prototype "Jawbone" headset for the show. Primarily to test component placement and where the tension points will be within the triangle of chin-back of head-ears. this will be done mostly with a polymer protoyping clay called Sugru. once refined, it will be laser scanned with a DIY laser scanning system i discovered online, then printed in pieces in the 3d printer.