Ben Waber.How to Make Almost Anything.Final Project

Final Project Model

I had been talking about doing a changing table for my final project, and that's exactly what I did. I cut the table itself out on the shopbot, but therein lied the trouble.

I milled out the frame of the changing table fine using the 3/4" thick MDF using a 3/8" drill bit, with each cut going at 0.3" depth and a feed rate of 20"/minute. For the shelves and decorations (robot arms, facial features, etc.) I used these same settings, but with 5/8" thick MDF. Apparently the wood was a bit different, because this caused some embers to go up and eventually ignite some of the wood collected in the Grizzly, but luckily it wasn't too bad thanks to some help from Jon and Kenny.

I also tried to use my step response board from a few weeks ago to detect weight so that I could sense when a diaper change occured. I found that by sandwiching liquid in a plastic bag between two sheets of wood with the copper plates on either side I was able to somewhat sense changes in weight. Unfortunately this process was fairly variable, since I needed to detect changes in weight of about 100 grams. In the end, I decided to use the sensor to detect when the person reaches for a diaper by looking at the change in the step response. This triggers a program which inserts an event into Google calendar denoting when you changed the baby's diaper. This is more important for babies when they're more than a few months old, since before then babies normally go to the bathroom after being fed. Still, it'll be useful to see exactly how often we're changing diapers!

Here's the code that I used to make this happen (use You need pySerial and Google's python library (included).