I use a number of film cameras that do not have any sort of built in light meter so I’m looking to build one that can slot into the hotshoe of the camera. Just a tiny device that can sit on top of the camera and display some sort of lux or lumens value along with suggested exposure settings i.e. 1/50 sec at f/8 etc.
I would love to use an e-ink display for this as I think it would allow for great battery economy and a small form factor. However they all seem to be hats leaving none of the gpio pins on most relevant boards free to attach a photoresistor.
Would anyone have any advice as to how I could achieve this? Essentially I think I just need a microprocessor of any kind (a pi pico?) with an e-ink display, a photoresistor (and a way to connect it) along with a tiny lipo battery.
Welcome to the forum!! Sounds like an interesting project!
While most of the HAT/shield type modules ‘take’ most of the pins they usually arent connected and can be used for other tasks, check out the picture down in the description of the E-Ink module for the Pico:
You list looks good! Ooops, it also seems I forgot to link the LiPo Shim, there is one for the Pico and the Pi computers, you’ll want this one here: Pimoroni LiPo SHIM for Pico | PIM557 | Core Electronics Australia
You wont need the Micro LiPo either! If you plug a USB cable into the Pico it will charge the battery!
To get a reading from a photoresistor(also known as an LDR) you’ll want to connect it like this: Using a Photocell | Photocells | Adafruit Learning System
The 10K resistor should still give you a good voltage swing as the LDR picks up more light.
