By Marc Bucchieri
This past month WMSI began developmental work on a new kit. The two-piece system creates a scenario in which a radio receiver is used to find a hidden transmitter, much like owls can use their super-accurate hearing to find each other. The Owl transmitter - receiver pair is intended to get students thinking about how to solve a problem like, say, searching for a fallen hot air balloon in the woods. Classroom projects with these units could include building directional antennas as part of an electromagnetism unit, practicing orienteering or radio direction finding, or sensor datalogging among others.
Prototyping with two different microcontrollers
At it’s core, each unit is a microcontroller linked to a radio transmitter. Our first round of prototypes compare the abilities of two different microcontroller-radio pairs: the Adafruit Feather M0 with LoRa Radio and the Arduino Pro Mini with RFM69 Radio Module. After following the accompanying product tutorials to get them both set up with antennas, we hooked up each unit to battery power and eagerly began testing.
Feather-based unit getting ready for outdoor testing
Obviously some amount of weatherproofing was necessary to keep our prototype safe from the snowy and windy conditions outside while testing the transmission range. Since we hadn’t gotten around to fabricating an enclosure yet, the simplest solution was to place the transmitter in a plastic box built to protect outdoor power supplies. Thus followed several rounds of testing to put both microcontrollers and radio setups through their paces.
Template to laser-cut a top for the receiver
The open-topped gray box was functional enough for the first few rounds of testing, but we wanted to make our prototypes a little more user-friendly. The next round of development focused on making the units self-contained. Both units were equipped with power switches, and the receiver was hooked up to a 16x2 character LCD so that it no longer requires a computer to display data. With these changes intact, we were able to run a few exciting trials in the woods of Bretzfelder Park.
Prototype Owls ready to play outside
As exciting as it is to have functional prototypes, these little radio units need a few more rounds of testing and design reiteration before they’re ready for the classroom. Stay tuned for more development news and Engineering Design Process posts!