555 timer Remote Capacitance Sensor - fluid level, body detector, touch sensor

RE: 555 timer Remote Capacitance Sensor - fluid level, body detector, touch sensor

AE7HD — Thu, 21 Mar 2024 15:01:09 GMT

RE: 555 timer Remote Capacitance Sensor - fluid level, body detector, touch sensor

AE7HD — Wed, 20 Mar 2024 12:55:24 GMT

hackaday.io/.../183506-remote-continuous-liquid-level-sensor-555-timer

RE: 555 timer Remote Capacitance Sensor - fluid level, body detector, touch sensor

Gururaj — Wed, 20 Mar 2024 02:27:24 GMT

Hi AE7H,

Very interesting design. Thanks for Sharing. I have few queries. If you could throw some light on them, it would be great.

1. What is the purpose of D2 at the out of 555 (Pin 3)?
2. When CL is not present, Will Arduino keep showing the value of C1 (100pF) ?
3. I am planning to power 555 timer, only when needed through a N-Channel MOSFET trigger by Arduino's Digital PIN. In this case, when can we start measuring Capacitance?
3.1. Should we Poll the "Pulse pin" and when it goes low, start the measurement?
3.2. After powering on, wait for few millisecond (for 555 to start) and then start measuring the capacitance?

4. Normally we take Off time + On Time and then calculate Capacitance. In here, you have mentioned only ON time would be considered. Can you explain more about this concept please.

Thanks in Advance.

Gururaj

RE: 555 timer Remote Capacitance Sensor - fluid level, body detector, touch sensor

dougw — Thu, 20 Oct 2022 18:08:21 GMT

Good idea to put the circuit close to the "capacitor".