Raspberry Pi – Assemble your temperature THERMISTOR with an XRF transmitter probe

I continue the series on my for a weather station wireless temperature sensors. Now that the transmitters are configured (see this article), It is necessary to integrate them into their housing.

Raspberry Pi Home Server - Assembler votre sonde de température THERMISTOR avec un émetteur XRF

The case comes to assemble. Here is the front housing :

Raspberry Pi Home Server - Assembler votre sonde de température THERMISTOR avec un émetteur XRF

There are :

  • The housing
  • A stack
  • Map
  • Resistance
  • A capacitor
  • Two connectors for add-on XRF
  • The connector for the battery
  • And the temperature sensor

Here's how all these small parts will be assembled :

Raspberry Pi Home Server - Assembler votre sonde de température THERMISTOR avec un émetteur XRF

At your soldering iron ! 🙂 Voici le résultat final :

Raspberry Pi Home Server - Assembler votre sonde de température THERMISTOR avec un émetteur XRF

Attention : The connector of battery in the photo is in the wrong direction. I thought it would be more convenient with respect to the sensor but in the end all. And I put a bit of Tin on the Central Connector for the battery (the square in the middle of the map beside PAD HERE) but a little too much at the time it didn't. I am well amused to arrange my nonsense :-p

Now that you have your transmitter it is time to test. Make sure you have a XRF module on map Slice Of Pi. Let's see if all this small world comes to understand !

  1. Understand the language used between your modules XRF. It is relatively simple as standard. A message is always of the type : aXXMMMMMMMMM where :
    • XX is the ID of the type transmitter [A Z][A Z]
    • MMMMMMMMM is the message in it even

    The length of the message is fixed. The unused characters will be replaced by -. The Protocol goes in both directions with the same for the reply or message to query structure. You will find here all instructions that you can send to your probe.

  2. Launch the terminal mini :
    Python ~/pyserial-2.5/examples/miniterm.py/dev/ttyAMA0
  3. Listen to the wireless transmitter. Here it is easy, simply put the coin into the slot and it is left for small messages on the screen :
    1._sshYou will receive several times on the message has–STARTED– on the part of our transmitter.
  4. Talk to our transmitter. Just say hello by sending the message has–HELLO—-. You should have answered : a–HELLO—-
  5. In my project I have two probes. Therefore, the difference between each transmitter. For this we will change the ID of the issuer. Attention I don't speak of the PANID (the equivalent of the Wifi SSID) but a username block.
    It to send the command has–CHDEVIDZZ where ZZ is the new identifier. You can put whatever you want. Then it is necessary to relaunch the transmitter with the command has–REBOOT—. Wait a few seconds and you should again have the startup message but with the identifier ZZ instead of –:
  6. Finally : ask the temperature ! Et oui car au final c’est ce que l’on veut 🙂 Il faut donc demander gentiment : aZZTEMP—–. The answer is immediate : aZZTMPA24.75. Et oui 24.75°C c’est l’été 🙂
  7. Last step : conserve battery power. By default our transmitter is lit all the time waiting for a command. It is possible to cyclically temperature sending. For this you must use 2 commands in the following order :
    1. aZZINTVL999X where you replace 999 by the interval you want and X by this interval unit : T = ms, S = seconds, M = minutes, H = hours, D = days
    2. aZZCYCLE—- will activate the cycle set with the previous command. The transmitter will activate all 999 X send information then go back to sleep. During his sleep everything is cut. Including the radio part. You will therefore have no response to your messages.

    You choose the frequency of reception of your measurements.

So this is our first case assembled and operational. Remains to assemble the second housing and not forgetting to give it another identifier instead of the ZZ !

The following will be a script of recovery measures with storage in a database.

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