Get a photoresistor working with the Pi

[razor7877]

Try and power a photoresistor using the Rasberry Pi power output pins and measure the light intensity with the GPIO pins

• [x] Manage to power a photoresistor with the Pi power output pins
• [x] Get the signal into the Pi GPIO pins
• [ ] Measure the light intensity using a Python script

[razor7877]

The photoresistors come from the Super Starter Kit UNI R3 Project by ELEGOO: https://www.elegoo.com/en-ca/blogs/arduino-projects/elegoo-uno-project-super-starter-kit-tutorial

[razor7877]

Here is the documentation for the starter kit: https://drive.google.com/file/d/1UbLdYMcaIgeKvDwNnbeMES71M-Zrgpef/view?usp=sharing

[razor7877]

The photocell used is of a type called a light dependent resistor, sometimes called an LDR. As the name suggests, these components act just like a resistor, except that the resistance changes in response to how much light is falling on them. This one has a resistance of about 50 kΩ in near darkness and 500 Ω in bright light. To convert this varying value of resistance into something we can measure on an UNO R3 board's analog input, it needs to be converted into a voltage. The simplest way to do that is to combine it with a fixed resistor.

[razor7877]

The setup used to try the photoresistor which doesn't work since all the GPIO pins are digital.

The 220 ohm resistor used to limit the input voltage

[razor7877]

The idea of using a Pi to get the photoresistor working has been abandoned (see #5) and an Arduino Uno R3 will be used instead (see #6)