We teach about circuits, sensors, programming, and data visualization at our local hackerspace. To reach a wider audience, we are introducing open hardware in a nearby public school. Our project integrated with a unit on solar energy, where students build cardboard houses with features to reject or retain heat.
We built an Internet-connected datalogger for use by about 60 students in the 5th & 6th grade science classes, measuring temperature in 14 houses over 5 days. We installed the houses & sensors on the school roof, showed students the hardware & software involved, and facilitated class discussion & graphing of the data. Each class looked at the performance of their houses and discussed patterns caused by weather, daylight hours, and mass & window treatments of the houses.
This website documents the hardware, software, and what we did in the school.<firstname.lastname@example.org>. If you have trouble making it work, let us know.
Occidentalis makes itself known under that name. If that doesn't work for some reason, you can log into the router and find the IP address; the most recently connected device is probably the RasPi.
git clone git://github.com/doceme/py-spidev cd py-spidev sudo python setup.py install
git clone git://github.com/petervizi/python-eeml
pip install thingspeak
git clone git://github.com/bergey/berrybasket.git
config.jsonhas several sections, one for each supported online data aggregator, currently just "cosm", and one for the CSV, "logfile". You can leave out any section that you don't plan to use. For Cosm, the required fields are:
We're using the MCP3008 chip to convert analog measurements to digital. The pins down one side of the chip are analog inputs; the other side connect to the computer. The aforementioned blog post has good pictures of which pins go to which Raspberry Pi connections. Our schematic (below) shows wiring up two ADC chips. We've also made a two-layer PCB implementing this design.
|Function||Part #||Manufacturer||Vendor Link|
|Analog Digital Converter||MCP3008||Microchip||DigiKey|
|Single Board Computer||RasPi Model B||Raspberry Pi||Adafruit|
|Screw Terminal||282834-4||TE Connectivity||DigiKey|
|13x2-pin ribbon cable||862||Adafruit||Adafruit|
|or RasPi T-Cobbler for prototyping||1105||Adafruit||Adafruit|
To develop skills and confidence with technology, beginners need systems which they can take apart, modify, and occasionally break. Open hardware hackers can help by writing good documentation, designing systems which are simple to understand, and contextualizing our work in our communities. People of various levels of experience learn that technology is comprehensible & controllable when they form connections to their current activities and build on their strengths and prior knowledge.
Groups of 3 or 4 students decided whether their design goal was to stay warm or stay cool, and built a solar house tuned to that goal. Each house started with the same cardboard frame, with a hole to act as a window. Students added cups of dirt, water, or sand to store heat, one or more layers of plastic wrap over the window, and aluminum foil & black paper to cover the exterior. One house frame was left unmodified to act as a control.
Visual representation and interpretation of data are key literacy skills. Using real data and computer graphing for this exercise encourages students to view their environment as something that they can model.
Prior to designing their houses for the rooftop experiment, students performed more controlled experiments in the classroom, with electric lamps substituting for sunlight. They measured temperature and prepared graphs manually.