halls
Advanced Member level 4
- Joined
- Nov 12, 2007
- Messages
- 110
- Helped
- 25
- Reputation
- 50
- Reaction score
- 3
- Trophy points
- 1,298
- Location
- Basque Country
- Activity points
- 2,271
power line noise pick-up
hi!
I am developing a device for proximity sensing using a capacitive sensor of my own, made of two conducting surfaces and a common ground band, big enough for human proximity sensing.
The problem is that power line's 50 Hz are affecting the measures. In this device it is important to stay low power, so, for that, I just sample at very low frequencies (below the 50 Hz...). So I though of a technique which consists on subsampling at a frequency for which 50 Hz frequency's alias is in the high side of the spectrum, and thus, can be eliminated with a simple digital low pass filter...
Can anyone tell me what am I missing? It seemed to work fine, but actually I am still experimenting some background noise which I guess comes from the power lines noise's harmonics...
So, could anyone suggest a better way to reduce this noise, or tell me if I am missing something with this technique?
Thanks in advance!
hi!
I am developing a device for proximity sensing using a capacitive sensor of my own, made of two conducting surfaces and a common ground band, big enough for human proximity sensing.
The problem is that power line's 50 Hz are affecting the measures. In this device it is important to stay low power, so, for that, I just sample at very low frequencies (below the 50 Hz...). So I though of a technique which consists on subsampling at a frequency for which 50 Hz frequency's alias is in the high side of the spectrum, and thus, can be eliminated with a simple digital low pass filter...
Can anyone tell me what am I missing? It seemed to work fine, but actually I am still experimenting some background noise which I guess comes from the power lines noise's harmonics...
So, could anyone suggest a better way to reduce this noise, or tell me if I am missing something with this technique?
Thanks in advance!