I'm embarking on a van build and would like it to have some data available through a web interface. I'm keen to use a RPi because I know my way around a Linux box and should be able to hack together the code from some examples I've seen online.
Electronics, on the other hand, is not an area of expertise. I've done some reading around and have a rough plan; I wonder if anyone would be so kind as to tell me whether I've got the right end of the stick, as it were!
I've got an old first gen Pi around somewhere, so will use this.
1) Water levels:
- I think I need this: https://store.ncd.io/product/i2c-shield ... -i2c-port/
- ...and this: https://store.ncd.io/product/ads7830-8- ... ni-module/
- ...to use these to measure the water levels in my tanks: https://www.ebay.co.uk/itm/5V-PRESSURE- ... g2XHlCKZxg (P=ρgh)
- The gas tank I plan to use can be sold with a pressure sender described as follows: "It is 0-95 ohm sending and has 2 wires attached"
- I understand I can use an rc timing circuit but every tutorial I look at prefaces with the fact that it's inaccurate. I appreciate that it's probably campervan-accurate but thought I'd try and make use of the spare channels on the ADC and have improved accuracy. Open to changing my mind if you folks think easier.
- This led to my reading about Wheatstone bridges. Would throwing 3 other 45 Ohm resistors and the sender unit into a circuit like this work for me?
(Edit: clearly not 100V input!! - This did remind me of another question I should have asked though... would the input voltage for the bridge just come from some pair of gpio pins on the Pi or direct from my 12V battery? Would it matter either way?)
I appreciate I'd then have some calibration work to do (as long as I can get the hardware and code working!) but I'm expecting linear relationships between the data from the ADC and pressure.
Should I start buying these things or stick to woodwork?!