Ive recently started to use dhts to measure humidity and temp. First I was interested in measuring temp of a warehouse and second the humidity of coffee beans. I ran into these issues:
- Warehouse is far from wifi access so I used nrf radios to send data to building with wifi to post data to Thingspeak.com for logging. Since warehouse is remote and without power I had to use solar rechargeable battery pack to power project. When I tested in the field the t and h measurements were off or at least seemed off. 5% hum and 51C. Now I understand the thermal effect you mention since I was testing it out in the sun in order for the solar panel to charge the battery pack.
So I could separate the panel from the rest of my setup but the warehouse is going to be hot. At what temp does that thermal effect kick in and start distorting my data?
- Humidity in the coffee bean. I've long wondered what those $500 coffee humidity testers work on for humidity. I have noticed a flat prism like tip at the bottom of the coffee container which I'm guessing would be one of the mirrors. Ok so my idea was to make a cheaper version of them but if air circulation is important then I would have to add a fan as well. I've been testing just the dht22 and hdc1080 locked in a closed Tupperware a inside a room and it's still all over the place, from low 60's to high 70's.
So cooling it to a certain temp would actually be better for the reading?