Serial Comms and Crystals

[richard]

malcom
before you go too far down this track you might like to research some other devices or at least have a way to calibrate these things. I now have three sensors in the same room 2x dht22, 1 dht11. the dht 11 reads 60% the dht22's read 46.3 and 49.5 right now @19.6C (tis as close as they seem to get) . real hum is anyone's guess , the readings tend to converge @ around 20C but diverge wildly below 10C and above 30C. there is some info on the web about bedding these sensors in or "reforming them" . not sure how fussy reptiles are , I do know how fussy the cold blooded half of the human race is

[Scampy]

Richard,

Thanks for the suggestion. I've been having some issues and have to agree that these sensors are not really suitable where precision is required. I added tabsofts suggestion, and I got as many short errors as I did Longs... I've also got several not connected errors. I think I'll look at something that uses a standard communications interface such as those suggested by Tim.

The humidity requirements of the snakes I keep are not that critical, but this probe is intended to be used to monitor the humidity in the container containing eggs in an incubator, where the humidity needs to be kept at a set range so they don't dry out.

[Charlie]

According to the datasheets, for the DHT22:
Operating range humidity 0-100%RH;
Accuracy humidity +-2%RH(Max +-5%RH);
Resolution or sensitivity humidity 0.1%RH;
Repeatability humidity +-1%RH;
Humidity hysteresis +-0.3%RH
Long-term Stability +-0.5%RH/year
DHT22 should be fine for your application.

[AvionicsMaster1]

Just for my own edification what temp and humidity are you looking to maintain? Google implied both need to be tailored to type of snake egg.

[Scampy]

Just for my own edification what temp and humidity are you looking to maintain? Google implied both need to be tailored to type of snake egg.

Royal Python eggs are typically incubated at 32c and 90% humidity