Something for the weekend: Two way Raspberry Pi Transceiver board with Etrv Guide

13th November 2015

When it comes to heating your home, there are a number of ways you can make it much simpler. Rather than attempting to set complicated timers or having to work out what the optimal room temperature is, you can control every aspect of your heating quickly and simply from a Raspberry Pi that is equipped with a radio transceiver PCB.

An ENER314-RT add-on board can allow you to monitor and control devices that need 433 MHz ISIM band control, all from your Raspberry Pi. This means you can use it to control your MIHO013 Smart Radiator valve – which is part of our MiHome home automation range – allowing you to fully regulate the temperature of each room.

Each eTRV controls a radiator valve, allowing you to easily regulate room temperature, set the standard temperature you want the room to be (this is defaulted at 30 degrees C), time when your heating comes on and report the room temperature and battery level (if requested).

Your eTRV is also able to exercise the valve, request battery voltage and diagnostic flags, and set the valve to open, closed or normal, turn low power mode on and off, and set the reporting time to 15 minutes (default is five minutes).

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All of this essentially means that you know exactly what your heating is doing and when it is doing it, allowing you to keep your home at a comfortable temperature at all times simply by using your Raspberry Pi.

Follow these simple steps to be able to access all of these features:

What you will need:

Hardware
– A Raspberry Pi B+
– Mouse, Keyboard, HDMI, monitor
– An Energenie Pi HATs
Two way Pimote
Energenie Smart radiator valve

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Instructions
Connect the Energenie RT board to the raspberry pi as shown in figure 1. Connect the raspberry pi to a USB port using a micro USB to USB cable. Connect a HDMI cable from the raspberry pi to the monitor. The cable can be connected to a computer, laptop or adapter which is switched on. Once the raspberry pi has booted to the desktop ensure that the RT board software (HopeRF_TRX 2014-12-09.zip & bcm2835.zip) has been saved unto the raspberry pi.

Ensure that two AA batteries are correctly installed into the eTRV. The red LED will begin to flash for a few minutes which indicates that the stem is being fully retracted to allow installation on to a radiator.

Install the bcm library if you have not done so already. To install the bcm library follow these steps:
1 – Enter into bcm2835 directory
2 – tar zxvf bcm2835-1.37.tar.gz
3 – cd bcm2835-1.37
4 – ./configure
5 – make
6 – sudo make check (This test should pass)
7 – sudo make install

The bcm library is a C library for Raspberry Pi (RPi). It provides access to GPIO and other IO functions on the Broadcom BCM 2835 chip, allowing access to the GPIO pins on the 26 pin IDE plug on the RPi board so you can control and interface with various external devices.

Now you are ready to run the program. Follow these steps to run the monitoring program:
– Go into HopeRF_TRX 2014-12-09 directory
– Type: chmod +x hoperf_trx
– Type: sudo ./hoperf_trx 242

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The monitoring program will monitor the transmitted data from all Mi|Home products. All Mi|Home products possess a unique sensor ID which the monitoring program will display. The sensor ID is required in order to control the eTRV. Once you begin to run the monitoring program (hoperf_trx) it will not display transmitted data immediately because the eTRV transmits once every 5 minutes. In the example above the sensor ID = 0x00017b. This sensor ID is represented in HEX format. It must be converted to decimal. 17b HEX = 379 DEC.

Now you are ready to control the eTRV. Follow these steps to run the eTRV_Menu program:
– Go into eTRV_Menu directory
– Type: chmod +x hoperf
– sudo ./hoperf –s 379

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As an example we will send the “exercise valve” command. The command will fully extend the stem then fully retract the stem. The command will not be accepted immediately. The eTRV will listen for a command after each temperature report which occurs once every 5 minutes.

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To send a set the room temperature to a specific value follow these steps to run the HopeRF-TX-RX program:
– Go into the HopeRF-TX-RX directory
– chmod +x hoperf
– sudo ./hoperf sudo ./hoperf –m (manufacturerId) -p (productID) -s (sensorId) –d (data for temp set ) –e (encryptioniD)

All these parameters are in decimal format:
– Manufacturer ID = 4
– Product ID = 3
– Sensor ID = 379 (Unique to each product)
– Data for temp set = Set target temperature, range 0°C to 30°C. Temperature format: 16 bit signed with 1 decimal place, so H’0000’/decimal 0 = 0.0°C, H’012C’/decimal 300 =30.0°C
– Encryption ID = 242

You can now control the heating in a room or across your home with a few clicks, saving you having to manually adjust each radiator in your house. This will help rooms stay at the best temperature and help you save money by reducing overheating.

With the great features available to you now, you’re sure to find that heating your home is so much easier.

Keep an eye out for our next project.

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