A $14 USB Thermometer That Works Well With Linux

[jboehm]

I got 2 of these off eBay last year shipped from China for $16. I pleased with them. There a a degree or so delta between the 2 of them. That's good enough for my needs. I attach them at the end of USB extension cords to get them away form the server. I live in a norther region were an AC unit isn't required. When it gets warm in the summer I ping a local weather station for the current temp. When the temp falls below the home temp my home automation server pings me and tells me I can open the windows.

[jarfil]

That's pretty expensive, compared to a simple overkill solution like an Arduino with a serial temperature sensor:

• Arduino Pro Micro = $3.80
• DS18B20 = $0.65
• 4K7 resistor = $0.0068
• Micro USB cable = $0.60
• Plastic case = $0.87
• Assorted wire, solder and stuff = less than $0.05
• TOTAL: $5.98

If you want to put 12 sensors all over your... rack? multiple drives? GPUs, PSU, heatsinks, water blocks? whatever:

• Arduino Pro Micro = $3.80
• 12x DS18B20 = $7.8
• 12x 4K7 resistor = $0.08
• Micro USB cable = $0.60
• Plastic case = $0.87
• Assorted wire, solder and stuff = less than $0.50
• TOTAL: $13.65

(Some assembly and soldering required. Prices include shipping. Valid for 2016-05-05 on AliExpress. YMMV)

[milkylainen]

Use a one-wire USB-adapter (ds2490). Then add a whole bucketload of humidity, temp, rain, light whatever sensors.

[elmom]

7€ (with the usual ~month shipping time): http://www.dx.com/p/81105

Good for some one off things, but all those suggestions would be good for more serious/permanent/bigger installations.

[SystemCrasher]

Use a one-wire USB-adapter (ds2490). Then add a whole bucketload of humidity, temp, rain, light whatever sensors.

If one has got some single-board computer (Pi or whatever) as their "automation core", which is handy anyway, e.g. since it could display some stuff via web or send SMS over USB 3G/4G modem, etc while it is easy to keep it operational 24/7) they could use GPIO to read 1-wire devices, Linux could do 1-wire over GPIO. This way one could add sensors to their systems at less than $1 price tag, being price of ds18b20 and wires.

But if we take a look a bit further, author of temperv14 got few other fancy ideas in backpack. Like doing OCR of camera image... to read out LCD of boiler lacking better interfaces. Whoa, funny way to read data from "non-cooperative" devices.

[pal666]

When the temp falls below the home temp my home automation server pings me and tells me I can open the windows.

if you have to open windows manually, it is not automation

[ChamPro]

I really like the idea of an easily monitored external temperature probe for home. Even more useful would be one that does temperature AND humidity.

[ssokolow]

I really like the idea of an easily monitored external temperature probe for home. Even more useful would be one that does temperature AND humidity.

AdaFruit has a tutorial for using DHT11 and DHT22 sensors with an Arduino and they're dirt cheap on eBay.

[Pander]

See also https://usb-ids.gowdy.us/read/UD/0c45/7401

[hiryu]

Michael,

Can you give us a diff of what you changed?

I'm extremely interested in purchasing 2 of these for my enclosed server cabinet so I can keep an eye on the temperature in the front of the rack as well as in back.

My server cabinet has all of its exhaust vented through ducting that leads through the wall of my small home office, but I'm still very concerned with the temps as we get deeper into summer, especially with the 2u 24 core server in there with 4 HDD's.


I think I'll write a check so I can be paged should anything get too hot so I can start shutting down things from work. I've been meaning to install nagios or sensu for monitoring anyway.