• Prototype testing

    kristina panos04/30/2016 at 21:55 0 comments

    I tested it all day long at the office yesterday. Works just fine, but the switch wires could stand to be longer. If I had some two-conductor stranded wire, I'd use that.

    The motor is pretty loud, but no one asked about it. It probably passes for a phone on vibrate, honestly, but I'm going to print a tight-fitting pouch for it out of Ninjaflex or something.

    Here's a demo video with it set to buzz after five seconds. Normal time is 20 minutes.

  • Okay, so no Trinket.

    kristina panos04/26/2016 at 03:57 0 comments

    I'm getting the same behavior as before with the Trinket when plugged into a computer versus a battery or a USB wall adapter. Basically, it doesn't work. I've decided to use an Arduino Pro MIni instead and power it with an FTDI to USB and a wall adapter.

    I've stitched up a prototype pad with five pockets in it. Three are under my behind and there is one under each leg. I've tested it with one and it registers my weight pretty well. I'm going to finish the prototype and figure out how to deal with the wiring.

  • Under pressure.

    kristina panos04/24/2016 at 17:09 0 comments

    I have a new working prototype that uses five pressure-sensitive switches connected in parallel to a digital pin. Now I just need to make sure it works on a Trinket and sew up a new pad.

  • A New Hope

    kristina panos01/23/2016 at 16:14 0 comments

    I found some pressure switches at Electronic Goldmine. They should work like the FSR, but in a binary way (I haven't done anything with them yet). Also, there are five of them. No matter how I shift my weight, the timer will continue to run as long as at least one of the switches detects me. I just saw that they have 5 for $5 or 10 for $6. I love that place.

  • Well, it works. Mostly.

    kristina panos07/11/2014 at 16:20 1 comment

    It works. It does what it's supposed to, as long as I'm sitting on it properly. Sounds like Apple made it, no? Except they'd make the pad white.

    I changed the code to make the red light come on when I'm supposedly sitting on the FSR. For some reason, this light blinks when powered from a wall wart whether force is applied or not. When plugged into a computer, it produces the expected bootloader ready blinkenlight, but is silent after that period.

    I'm scheming to extend size of the the force-sensing area without compromising the FSR. Wish me luck.

  • Testing, testing.

    kristina panos07/05/2014 at 13:24 0 comments

    I am sitting on this skinny, bendy resistor with two minutes to go into a 20-minute test. She's all soldered up and living in her tic-tacs box. I still need to sew the pad up, but I'll wait until I'm sure it works.

  • Let's motor.

    kristina panos06/29/2014 at 13:29 0 comments

    I'm back on the horse with this project, and my finger has healed nicely. I've decided to use one or two of these tiny motors mounted inside the tic tac box for feedback. I think they come with a tiny piece of double-stick tape; if not, I'll use a bit of hot glue or something. 

  • project log: the day I cut my finger

    kristina panos03/24/2014 at 03:28 0 comments

    So, the pad I'm making should be durable, right? I'm going to sit on it for roughly forty hours per week. I decided I would use interfacing on both pieces, which is this stuff you can iron on to the wrong side of fabric to make it stronger and stiffer. 

    Anyway, so I'm also going to put a thin layer of batting in there, too. I'm not worried about feeling the FSR, but I figure I can slow its wear by making it comfortable. Batting is the key ingredient of a quilt sandwich and the kind I have feels like the inside of a sweatshirt or a cute little lamb. 

    I got the fabric and the batting cut and started on the interfacing. I have one of those rotary cutters which is like a ridiculously sharp pizza cutter for fabric and fabric accessories. You cut against clear plastic rulers and the whole idea is awesome until it isn't and you're reminded how sharp they are. It's an OLFA, after all. So yeah, I cut my pinky. I'm going to look into a chain mail glove.