High folks,
I am currently developing the electronics to read a cryogenic liquid level sensor. This sensor uses the change of capacitance between two electrodes to determine level of the liquid. I have designed a circuit using a LM555CM to generate a square wave read by PD5 on the ATMEGA328P. I just wanted to get the opinions of those on this forum of my approach and if you think that there my be a better approach to meter capacitance using the ATMEGA328P.
Capacitance Ranges change based on the length of the sensor, but are between 50pf and 450pf. And resolution is a priority. Although with my current setup I am getting a resolution of about 1/2 inch sensing length.
I have attached a picture of the relevant portion of the circuit design. (the MCP3422 is for reading thermocouples in case anyone was wondering)
