For my solar project I wanted to take advantage of the fact that solar is an inherently noisy source of power—how much energy we can harvest depends on the angle that the solar panel is placed, whether there's a shadow cast on any part of it, if a cloud goes over the sun, etc.
My plan is to detect when the solar panel is getting sun by monitoring when the LiPo battery it is plugged into is being charged, and then turning that data into a drawing, first on the computer, and then hopefully with a drawing machine for the final project.
Bill of Materials
Solar monitor: $57.84
- 5V 1.2W Solar Panel - ETFE: Solar panel ($14.95)
- Male DC Power adapter - 2.1mm: Solar panel to adapter ($2.00)
- Adafruit Universal USB / DC / Solar Lithium Ion/Polymer charger: Solar to LiPo charger ($14.95)
- Lithium Ion Polymer Battery - 3.7v 2500mAh: Lipo battery ($14.95)
- HiLetgo ESP-WROOM-32 ESP32: Microcontroller ($10.99)
Drawing machine: TBD
- Solenoid switch
- Linear actuator
- Stepper motor
Some questions I have to figure out:
- How do I test for the best angle for my solar panel?
- What is my power draw for my microcontroller/circuit setup? How do I make sure that my LiPo battery is never fully charged (or else I can't detect when the solar panel is charging it), but also never fully drained?
- Do I still need a voltage divider (to drop the 4V+ battery voltage to 3.3V for my ESP32) if I'm only interested in whether the battery is being charged (binary true/false) instead of percent charged?
Solar monitor
Here is the solar half of my project, waiting to be soldered:
https://learn.adafruit.com/adafruit-bq24074-universal-usb-dc-solar-charger-breakout/pinouts
https://github.com/tigoe/LightProjects/blob/main/TelephoneDimmer/RotaryDialDimmer0003/RotaryDialDimmer0003.ino https://github.com/tigoe/timepieces/blob/master/MovingLightClock/MovingLightClock001/MovingLightClock001.ino https://github.com/tigoe/Wifi101_examples/blob/main/ArduinoHttpClient_Examples/HttpClientGetJSON/HttpClientGetJSON.ino
Drawing machine
https://www.nationalgeographic.co.uk/photography/2020/12/longest-known-exposure-taken-by-makeshift-camera-forgotten-inside-uk-telescope
https://makezine.com/2009/07/30/how-to-build-a-beam-solarroller/
http://solarbotics.net/library/circuits/se_t1_mse.html
https://create.arduino.cc/projecthub/GadgetsToGrow/control-servo-power-with-a-transistor-3adce3
