Tag: temperature

Xiaomi Mijia Bluetooth-compatible Thermometer 2 Electric Humidity Smart Home Wireless Hygrometer LCD Digital Moisture (WHL #91)

Some new gadgets have been sitting here for a while – couldn’t be arsed to write about them last week

It’s pack of three Xiaomi Mijia Temperature + Humidity Monitor 2 (what a name), product number seems to be LYWSD03MMC. They cost me 15.58€ in December, inclusive of shipping and indeed one CR2032 coin cell per unit. Units from German distributors are more like 10 to 15€ each with negligible volume discounts – and shipping cost on top of that.

Anyway, here’s an explosion view from the unit, likely made by Xiaomi and not the seller:

I’ve been using other cheapo thermometer/hygrometer units for the past, well, probably 10 to 15 years, they’re really inexpensive at sub-2€ each and run on LR44 batteries basically indefinitely. […]


250g-500g 1/0.5mm Lötzinn Lötdraht Löt mit Flussmittel Lötkolben Lötstation DHL (WHL #68F1)

(Follow-up post to the solder test of WHL #68)
While we’re at it – I couldn’t resist testing the flux percentage. Which also resulted in having large samples for a visual comparison. Contrary to my expectations, the lead-free solder wasn’t the one that stood out…

First things first. New batch, same naming scheme as before. Since I already measured weight per meter, I just picked one sample length from a (new) lead-free U1.0 wire and cut the others to expected length. 100cm of that stuff is 5.42(196)g, for comparison. […]


Sensirion SGP30 and Bosch BME280 air sensors (WHL #64)

Small air sensor modules for today!

The Bosch BME280 has been in use on my ESP modules across the apartment since I discarded the unreliable DHT sensors, DHT22 in my case. It’s a combined temperature-pressure-humidity sensor, contrary to the much cheaper BMP280 or the predecessor BMP180, which lack the humidity part (pretty much vital indoors, while pressure is just a gimmick). They are sold in many similar versions, I’ve always picked the GY-BME280 module in 3.3V flavour (“GYBMEP”), as the sensor can be operated from 1.71V to 3.6V which is handy for different MCUs. […]