MTM and Final Project Update


For this week, we were supposed to build two MTM Snap machines, one per section. I missed the class on Monday because I was on my way back from London, so I didn’t really know what to expect. The section on Tuesday went over how to cut out parts for the MTM machines, and we all met in the shop on Wednesday evening to assemble the machines. A huge thanks to Novysan for cutting out the pieces for the CBA section!

Putting the machine together was actually a huge pain. For one thing, we had way too many people for the task. Secondly, Jonathan had a sample machine for us to look at, but it was still incredibly easy to get the parts put together backwards and/or inside out. The flexure joints are cool, though.

I had the (very) unrealistic expectation that this was going to come together like a piece of Ikea furniture. Wrong! There was no written documentation and some components, like the spindle, are very intricate and required Jonathan’s special supervision. Unfortunately, I had a final project presentation on Friday for another class, so I was too busy to return and help out on Thursday.

I also spent some time this week working on my my final project. The current plan is to make an interactive cat toy.

  1. 1)The basic version: uses a PIR sensor that triggers a stick-and-felt cat toy to rotate whenever it detects motion.

  2. 2)The advanced/”stretch” version: uses a microphone to detect sounds near the toy. The toy moves whenever the cat’s meow is recognized.

This is what the cat toy looks like, I’ll be rotating the stick around the +z axis.

Material-wise, I had ordered a PIR sensor and a servo a few weeks ago. I spent the weekend interfacing those components with my fabduino.

Separately, the PIR sensor and the servo worked as expected. Together, however, the fact that the servo is consuming power from the same source as the PIR sensor seems to disrupt the PIR sensor and make it report motion all the time. I’ll have to look into it more, circuit diagrams may be involved.

Things I need to develop:

  1. -Harness for the actual cat toy that interfaces with the motor

  2. -Getting the servo to play nice with IR sensor

  3. -Making sure the servo can actually move the cat toy

  4. -Something to house the fabduino and the IR sensor (don’t want spinning toy to trigger the IR sensor)

  5. -Stretch: Connect microphone to fabduino board

  6. -Stretch: Process audio signal from microphone to detect cat meow

  7. -Stretch+: Process audio signal on the fabduino.

Dates: Aiming to finish the PIR sensor version of the cat toy by December 13th. I should then have almost a week to work on the audio processing version.


Wait, you mean it’s not from Ikea?