I have one of those little weather stations from Lidl which have a radio controlled clock, inside and outside temperatures, air pressure and a hygrometer. The temperatures and pressure are accurate as I can verify them against other instruments I have, so the hygrometer is probably quite good as well.

What about a Tempo Disc ? We bought one after reading an earlier thread on workshop humidity.

It is a £30 data logger rather than a display, but can be accessed at any time via bluetooth, with the logs showing on an android/IOS app as a graph showing humidity, temperature and dew point over time, Nice and compact, a bit bigger than a 50p coin and runs on a 2032 button cell.

They are made in the UK and if you are serious about wanting a really accurate hygrometer they will test against a standard and issue a calibration certificate for an extra fee. If you want to fix it in place, the silicone hangers were out of stock when we got ours, so I downloaded an STL from Thingiverse and printed one.

Brian G

another thumbs up for the dehumidifier got mine from Machine Mart. drain it daily this time of year. my cheepo hygrometer never moved much but the dampness went and the rust stopped so no idea what it's measuring

you ask for accurate ? what is being used as a standard to check

Another use ford a humidifier, we've stopped using the tumble drier, just hang washing in smallest room on a clothes horse (winter-hedge if you're from my neck of the woods), switch on the dehumidifier and it dries as is by magic

Again, wet bulb. You only need to get one old fashioned high quality thermometer from a laboratory supplier and make alternate wet and dry measurements.

Alternatively just go with cheapo because after a while you will probably realise it is only the changes that are interesting and a rough value is enough. Ie when a warm damp front comes in you might be interested to see if he shed is damper even though you haven't opened the door, or if you 6 hour session sweating over hacksawing 500 widgets has made it worse.

I have a fully home made insulated garage & workshop made from fridge panels. Video of manufacture on youtube. I also would like one of these devices to see what temp differences i have inner to outer. So will be interested in the answers to this question. My brother in law does have one of the Aldi ones but i'm not sure how accurate it is.

Steve.

Can't vouch for accuracy but I use a couple of these:-

One to monitor the humidity inside a filament storage box and one outside the box in the workshop. From several suppliers at Amazon and similar for a couple of quid. Different styles and colours some have equal size temperature and humidity readouts. Press-fit into a hole about 45mm x 25mm or just leave them loose. Make useful fridge thermometers as well. More on filament storage box *** HERE ***

John

For those feeling more adventurous I designed an Arduino based Dewpoint Monitor for the workshop that displays the various parameters and if the dewpoint comes within a defined limit, it enables a power outlet to turn on heaters. The trigger point is defined in the Arduino code. More efficient than just leaving a heater on.

I ran some 'proper' PCBs for our club members and have 5 or so left for first takers via PM or via my blog. If there is more demand than I might consider running some more boards. There is a download PDF write up on my blog via the link below

Dewpoint monitor

Hi Adam

I will follow up on the PM.

The DHT22 is the more expensive version which has better specifications. Its temperature measuring range is from -40 to +125 degrees Celsius with +-0.5 degrees accuracy, while the DHT11 temperature range is from 0 to 50 degrees Celsius with +-2 degrees accuracy. Also the DHT22 sensor has better humidity measuring range, from 0 to 100% with 2-5% accuracy, while the DHT11 humidity range is from 20 to 80% with 5% accuracy.

The DHT22 is more tolerant of a long cable length for remote monitoring.

Alan

Edited By Alan Wood 4 on 01/01/2022 15:12:41