Braeden Hamson
- Feb 18, 2016
- 240
- Joined
- Feb 18, 2016
- Messages
- 240
I built an instrumentation amplifier following this circuit exactly.
https://www.allaboutcircuits.com/textbook/semiconductors/chpt-8/the-instrumentation-amplifier/
I used a load cell out of a wii balance board. And one output I have two LEDs in series to monitor the output voltage of the whole circuit. When I apply pressure to the load cell one way and another the led's become darker and brighter. This is good, it's what I was looking for. However, the problem is that if I bring my hand near the load cell without touching it the lights become brighter. I connected a jumper lead to the load cell body and connected it to ground, which didn't help. Interestingly when I detached the lead from the load cell and it was still connected to the breadboard ground and raised the wire up the output voltage of the circuit goes up. So I'm certainly getting RF interference. My question is how I can I minimize this effect or normalize it?
https://www.allaboutcircuits.com/textbook/semiconductors/chpt-8/the-instrumentation-amplifier/
I used a load cell out of a wii balance board. And one output I have two LEDs in series to monitor the output voltage of the whole circuit. When I apply pressure to the load cell one way and another the led's become darker and brighter. This is good, it's what I was looking for. However, the problem is that if I bring my hand near the load cell without touching it the lights become brighter. I connected a jumper lead to the load cell body and connected it to ground, which didn't help. Interestingly when I detached the lead from the load cell and it was still connected to the breadboard ground and raised the wire up the output voltage of the circuit goes up. So I'm certainly getting RF interference. My question is how I can I minimize this effect or normalize it?