Hi everyone,
I was wondering if I could get some opinions on selecting a humidity sensor for a project. I am looking for a relatively cheap sensor which I can interface to a Spartan 3. I already need to use a 10-bit ADC in my design to convert a voltage signal, so I was planning on reading a (converted) output voltage into this before sending it to the processor.
I don't have many constraints thus far, except:
- accuracy is the biggest factor
- cost <$20
- enables sampling of at least 5 times per sec
- has to interface (eventually) with a spartan 3
- it's part of a temperature/humidity sensor project, so the greater operating temperature range the better.
- I am in Australia! (poor me!) and thus need to order from RS, Farnell or any distributor which will NOT charge me a ridiculous shipping fee (budget is a factor in this project).
The things I need advice on are as follows:
- when considering the above, should I be looking towards capacitive or resistive sensors?
- what additional circuitry is required for signal conditioning? (i.e. obtaining an output voltage signal for input to ADC). I've seen lots of 555 designs, FVC examples and fancy RC circuits, but to be honest i don't know which scheme would suit the project best (or whether i should give up and buy a component with voltage output).
Does anyone have a bit of experience in this area and can point me in the right direction? Any help would be much appreciated!
I was wondering if I could get some opinions on selecting a humidity sensor for a project. I am looking for a relatively cheap sensor which I can interface to a Spartan 3. I already need to use a 10-bit ADC in my design to convert a voltage signal, so I was planning on reading a (converted) output voltage into this before sending it to the processor.
I don't have many constraints thus far, except:
- accuracy is the biggest factor
- cost <$20
- enables sampling of at least 5 times per sec
- has to interface (eventually) with a spartan 3
- it's part of a temperature/humidity sensor project, so the greater operating temperature range the better.
- I am in Australia! (poor me!) and thus need to order from RS, Farnell or any distributor which will NOT charge me a ridiculous shipping fee (budget is a factor in this project).
The things I need advice on are as follows:
- when considering the above, should I be looking towards capacitive or resistive sensors?
- what additional circuitry is required for signal conditioning? (i.e. obtaining an output voltage signal for input to ADC). I've seen lots of 555 designs, FVC examples and fancy RC circuits, but to be honest i don't know which scheme would suit the project best (or whether i should give up and buy a component with voltage output).
Does anyone have a bit of experience in this area and can point me in the right direction? Any help would be much appreciated!
