Inexpensive LV compatible temperature sensors

[BowenM]

I thought about posting this in the LV form, but no boards really seemed to match other than this one.

Anyway, I'm working on a small home project for my father.  You see, he has a greenhouse in the middle of nowhere that he uses to garden in the middle of winter.  Keeps him sane!

As a gift to him this year, I want to set up a wireless (preferably) temperature monitoring system because sometimes it gets too cold at night and kills off some of his plants.  I'd like him to be able to stick temp probes in the ground and have it transmitted back to a computer in his house so he can monitor and log.

I was initially thinking K-type thermocouple wire for the sensors.  Cheap, inexpensive, can go back to some DAQ box in a shielded area of the greenhouse so that the actual electronics were protected.  But, I'm having a hard time finding a reasonably priced DAQ box that I can rig to transmit back to the house. 

Thoughts?  Suggestions? 

Spoiler

By the way if everyone wants to turn this into a home DAQ/Automation using LabVIEW thread I would find that very interesting 🙂
I have a whole pile of projects I want to do in my next house.

[RavensFan]

Measurement Computing tends to have some less expensive stuff.  Here's a channel T/C.  https://www.mccdaq.com/usb-data-acquisition/usb-2001-tc.aspx  But still $99 might be a bit much.

What about any weather station type of setup?  Some might be just an LCD display, but with maybe some newer, higher tech ones would allow logging to a PC.

Another thought would be to do something with an Arduino or Raspberry PI.  If it was my home project, I'd lean towards that.  RPi's have wireless.  It wouldn't be LV programming on it, but wouldn't be that hard.  And there are some 3rd party toolkits out there to do Arduino's or Pi's in LabVIEW.  And the base station in the house to view the temperatures could certainly be written in LV.

[BowenM]

Thanks - I'll have to keep an eye on the measurement computing stuff.  Sometimes good deals show up on ebay and something like their E-TC looks like it would work very well.

I've looked into Arduino some but have never used one with LabVIEW.  All of the packages I've seen so far are focused around the uno and only USB which isn't that convenient of an option for a greenhouse 🙂  Maybe I should look closer though - there is an 8ch mux thermocouple shield for $50!

[Hooovahh]

In the office we use something like this.  Which has temperature humidity and dewpoint read over the network and has a web server that can be queried.

But if you want real cheap I'd say look into the DHT11 or DHT22 sensor, which is either $5 or $10, paired with an arduino compatible board (I prefer the Teensy LC for $12 but there might be other options).  Then using the premade library, read the temperature and humidity, and send it back over serial, where LabVIEW reads it.  Temperature and humidity for about $20.  How accurate?  How precise? and How to calibrate it might be more difficult.

If you want something slightly more standard you can have a thermocouple read in.  NI has the TC-01 which is a simple USB that reads a thermocouple for about $100.  Another cheaper option would be the Arduino paired with something that the Arduino can read, like a signal conditioner, or a MAX31855 for $15 or so.

Any of the Arduino options will take some custom code, but reading from a sensor using the premade library, and then spitting it out over serial is something that can be done with no previous Arduino experience by following some examples online.

[Henrik_Volkers]

Currently I think the ESP8266 (wifi onboard)  together with a digital temp sensor

and OLED display   will be around 10 bucks ...   double and you have a temp/humidity and air pressure sensor  and a power supply ... programming can be done with the arduino IDE

EDIT: Reading/monitoring/display  the wifi sensors can be done in LabVIEW 😄

[Hooovahh]

Yeah the ESP8266 is nice and cheap, but only if you have the means to program it.  The Teensy or Arduino solutions I mentioned have USB built in and don't require any programmer, or USB to UART.  I didn't know what resources OP had, and we haven't had a clear need to display it independently.  Here are a few projects using the DHT22 I mentioned earlier with the ESP8266.

https://www.hackster.io/Hernanduino/wifi-esp8266-and-dht22-sensor-09d455

https://www.losant.com/blog/getting-started-with-the-esp8266-and-dht22-sensor

[Blokk]

I just used for a similar project DS18B20 Programmable Resolution 1-Wire Digital Thermometers from Maxim. They can be connected parallel, and each sensor has unique IDs. Even better, they have programmable alarm function.

My setup is very simple: I have a tiny Python code running on a Raspi 3, and broadcasting all collected data via an UDP server (as I remember it is like 3-4 lines in Python). A LabVIEW UDP client with display/logger is running on a PC, but you can use anything with simple UDP clients (Android, etc...).

As I remember one starting point was here for Python example: https://www.modmypi.com/blog/ds18b20-one-wire-digital-temperature-sensor-and-the-raspberry-pi

And these sheathed sensors are ready for usage: https://www.amazon.de/gp/product/B00CHEZ250/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

[BowenM]

Thank you all for your recommendations.  Looks like I have a bunch of research to do... but the fun kind 🙂

So, back to my first comment... does anyone have any fun home automation projects they've done and want to brag about?

[Henrik_Volkers]

---

@BowenM wrote:

Thank you all for your recommendations.  Looks like I have a bunch of research to do... but the fun kind 🙂

So, back to my first comment... does anyone have any fun home automation projects they've done and want to brag about?

---

Well, since 10a I run a Beckhoff PLC in my home.  Would have loved to use LabVIEW, but the number of needed (mostly line voltage) IO , ....  for my use cases the PLC fitted better and  KNX (EIB) was much to expensive.  A great source of vendor independent PLC software for home automation is OSCAT  a german side, but you get english  lib documentation.

[Sam_Sharp]

Home, but not in the typical house sense. I live on a narrowboat and I built a monitoring system using an sbRIO initially and then ported it over to a RPi.

I gave a presentation about it at a user group meeting: https://forums.ni.com/ni/attachments/ni/5153/124/1/BMS%20Presentation.pdf