Reflection based distance.
Bending changes resistance.
References: Mini Powersupply
Li-Po charging IC, probably with 5V/USB charging
Pass through external power
Monitoring the battery status
A breadboard has 2 power rails, it would be nice to supply different voltages to both of them, so the first version could adjust from 0-24V. To keep it small a lithium battery could be used and two adjustable buck-boost converters with two voltmeters. Max 500mA-1A current is plenty.
Version 2 could have a negative rail, or an inverting buck boost power supply, also Ammeters.
The forecast for tomorrow is a sunny 28°c (82°F) and the low that evening is 16°C (61°F), we’d open the windows.
The forecast is for rain and belbow the desired room temperature tomorrow, even if cold that evening, it doesn’t want to open up.
Using weather APIs it would make intelligent decisions on when to cool, and based on historical temperature data it would know how long to cool for, it takes and hour, or five to reach the same outside temperature. The lowest temperature isn’t around for hours, so it would learn the heating/ cooling profiles for the room. Lowest temperature at 3am, takes three hours for the temperature of the room to drop that amount. Then from 2am to 4am it should be on. It can happen that the outside temperature is cooler than the inside and that is still true all day, but that ignores the home insulation, so there might be a point it should stop if the rate of change (derivative) of the forecast temperature is greater than the closed room rate of change.
APIs and a few simpler algorithms, a window fan with shutters for rain and sunlight. Temperature and confrontation (end stop) sensors.
Bringing your environment.
My sister came back from Hawii and the heat is too much. I have heard about Cosplay cooling suits, so a modification of one of those would be great. If you can cool, with a few methods it’s easy to heat so why not both. In the desert it gets really hot and really cold, also in space.
I could see decent performance passively for heat, but cold needs something else.
The guitar idea is better but I should start somewhere, there are a few laser harp designs, with a without frames, I could do one that is the same a a break beam sensor, but with a few of them and a speaker.
References: Make, Instructable
Seems like improvements would be to maintain an exact temperature so that the plastic sheet wouldn’t burn, and the vacuum table could be more of a fine grid. There is a plastic heater thing that has a heating element under a hollow bar of metal. So a double sided metal plate like a panini press would be the best for heating evenly. I label my solder with what temperature it melts at, determining the right temperature for a type of plastic would be ideal, I’m thinking halfway between melting and browning/burning. A better vacuum plate would be next.
It could start with a simple fan. This one uses a hall sensor (using a magnetic field) to measure the rotational speed. This is awesome, but it could still go further.
I ordered 144/m APA102 which are fast enough to use for POV.