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Author Topic: Cheap Wireless for Analogue Sensors  (Read 2354 times)


February 18, 2015, 08:41:44 PM
Reply #1

bkenobi

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Those require a microprocessor to transmit the data.  In order to transmit a temperature for instance, you would basically need a temperature sensor, a controller (Arduino nano for example), and the transmitter and then a receiver and controller to receive the data.  In order to have it work, you would also need to write some code to transmit and receive for each end.

Not only is this possible, but there are many examples of doing just this on the arduino.cc forums.  However, I would caution that unless you are looking at something that is not already available in a wireless sensor, you might be better off purchasing off the shelf sensors (think weather station 433MHz type) and then concentrating on using an Arduino or Raspi with a 433MHz receiver to decode.  There are several advantages to this including: warranty, weatherproofing, less development time/cost, most likely cheaper depending on how you source things, etc.

I'm actually looking at adding some localized weather info to my HG setup right now.  From what I've found through research, it is far easier to buy an off the shelf weather station that has been decoded and drivers developed and a 433MHz superheterodyne receiver than to build something myself and then figure out how to handle weatherproofing etc.

Obviously, if you are looking at something that's not already available, you are in a different boat.  But, it's not as simple as soldering a transmitter onto a sensor and having it work.

February 18, 2015, 11:20:12 PM
Reply #2

CptJack

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I'm a huge fan of the MySensors project. I have a network of them that I was using with my Vera, but I haven't converted them to MQTT for HG yet. I'll put up some information when I do.

February 19, 2015, 04:32:59 AM
Reply #3

bkenobi

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That's an excellent compilation of various sensors and the code to get them going.  There are several there that aren't available in a premade wireless version that I've seen.  But, if you want to make the sensor wireless it will take a little coding and a different gateway than is currently available...unless you spend a bit more and go WiFi.

February 19, 2015, 05:44:58 AM
Reply #4

CptJack

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I think it's incredibly cool. They're wireless by default (mesh topology, even), and you build the gateway yourself - I built the Ethernet gateway for Vera, but I think it's just a code update to convert it to MQTT. I saw someone talking about MQTT in HG, so I'll figure that out and then write the program and modules for HG.

I just did a little write-up about my experience with them here. I'm really excited to get them up and running in HG, since I use them for a ton of things. Right now, I'm sitting in my basement re-writing my theater scenes from Vera to HG (now that I have the Yamaha AVR sensing working pretty well), so maybe next week I'll start on the MySensors.

February 19, 2015, 04:36:52 PM
Reply #5

bkenobi

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Interesting blog entry, but you didn't list what you were using for a wireless board.  I'm curious of the total build cost per sensor.  I have been looking at adding an external weather station for wind speed, wind direction (maybe), temperature, and humidity.  The cheapest I've found a station for (new) is $60USD from Costco.  The sensor is a monster though.  Same as this one from Amazon just cheaper price:

http://www.amazon.com/Acu-Rite-Professional-Wireless-Weather-Software/dp/B00NI57C14

There are people who have decoded the signal for Arduino and Raspi, so it is likely simple to include, but I really don't like the thing.  But, I'm not looking to spend what Oregon Scientific or others want for a more compact unit at this point ($250-500USD).  If I could build something comparable for a fraction of the price, I'd be very interested!

February 20, 2015, 12:02:09 AM
Reply #6

CptJack

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Full build details are best left to the MySensors site (since they're improving it all the time), but they use nRF24L01+ 2.64Ghz transceivers. Total cost per sensor can be $10-$20 depending on what you want, but buying in bulk can reduce that even further.

February 20, 2015, 07:33:55 AM
Reply #7

bkenobi

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I wasn't aware that the nano was so cheap.  I don't need one now, but found that they are available for ~$2.50USD shipped, so I bought a couple this afternoon.  I have an extra 433MHz receiver on order and at least one 433MHz transmitter in my box of parts, so I'm thinking I may look around on the MySensor site to see what kinds of stuff can be done.