With apologies to Tyler Crumpton for posting something so similar to what you were working on – I hope you finish the Sherlock Holmes "Case Hat" and write about it for us!
Although my kids weren’t terribly excited about helping to build hats, they were excited to see the finished Dog Safety Hat working ( I was going to post final pictures last night, but ended up sewing on this hat instead) In fact, they both wanted to wear it to school for crazy hat day. My wife and I thought it would be too distracting to wear during the school day and disallowed it, but I think they’ll still manage to find ways to have fun with it.
Since the vibration sensors didn’t have the sensitivity I was looking for, I didn’t see a good way to complete the Treasure Map Hat without compromising some of the fun value of it. But because I’ve already finished a hat for my daughter, I figured I should do something for my son – I try to keep things equal when I can, although I’m sure they’d be eager to point out differences if you ask them!
I had an HC-SR04 ultrasound sensor lying around anyway (I’m supposed to be investigating the possibility of using 4 of them as an anemometer, but I keep getting distracted) so I decided to repurpose the Gemma I had for the Treasure Map Hat and build a Spy Hat. If you read The hats we decided not to make you may remember that one of the possibilities mentioned was a Spy Hat with buzzer and LED for Morse code and an ultrasound sensor to detect someone sneaking up on you. The sensor I have wants two Gemma pins, leaving only one for the LED output, and no spares for the piezo buzzer, so noise is out, but as it’s supposed to be a Spy Hat, I think the noise would have been counter-productive anyway.
I figured a baseball style hat would be the easiest to use, especially as I’d used one for the vibration sensor testing in the Treasure Map Hat, so it already had a Gemma sewn to it.
My wife had offered a National Air and Space Museum hat, which I thought would be appropriate to modification with high tech sensors, but my son wanted it to be his Adventure Guides hat, presumably because that then gives him an excuse to show it off to his friends.
I’m good with that – it will actually fit in with bristlebot building and racing that I have planned for our December meeting.
So… since the deadline rapidly approaches, I am planning to make this hat very simple: a rear facing sensor will sense the distance to the nearest object behind the wearer, and a NeoPixel LED sewn to the brim of the cap will color green if the sensor detects nothing, yellow if the sensor detects an object approaching, and red if the object is too close.
Let the sewing begin!