Is 868MHz a standard frequency? Can I use an arduino to send/receive data?

Projects Networking, Protocols, and Devices
1

I want to automate the heating system in my home. I have a gas boiler that comes with a remote thermostat/controller. I want to extend its functionality by adding time based automation.

To accomplish this, I need to be able to see the data packets that the remote broadcasts when I press various buttons, so I can program an arduino to replicate them.

My problem is, that the remote's datasheet says that it operates at 868,35 MHz, but in most online stores I could only find 868 MHz transceivers. Can I assume that it's a standard value and they will be compatible with each other? Does that 0.35 MHz matter?

Also, can I use this product to send/receive data? The description mentions some sort of encryption, not sure if that's gonna be a problem.

Sorry if this is a very stupid question.

2

Yes, follow this tutorial to learn how to use it.

3

To even begin to reverse engineer the RF communications you'll need to know what transceiver type or RF modulation scheme is being used. If this isn't on the data sheet then you will need to use some expensive test equipment to figure it out. For a beginner this isn't a practical thing to do.

The quickest/simplest/easiest solution would be to disconnect the existing receiver and replace it with something that is Arduino friendly.

If your heating systems uses moving parts (pumps, motors, valves etc.) then you definitely need to program in protection against 'short cycling'.

4

SparkyTD:
My problem is, that the remote's datasheet says that it operates at 868,35 MHz, but in most online stores I could only find 868 MHz transceivers. Can I assume that it's a standard value and they will be compatible with each other? Does that 0.35 MHz matter?

868Mhz is a standard band, but only where you are allowed to use it.

What frequencies you can use, without needing a specific licence, varies between regions and countries.

Even within the 868Mhz band, if permitted in your country, there can be differences in the exact frequencies, powers and duty cycles you are permitted to use.

Whilst it would be nice if there was a universal 'standard' frequency, unfortunatly there is not.

You will also find that different tranceivers are not directly compatible with each, they often use completly different software for instance.

5

mikb55:
To even begin to reverse engineer the RF communications you'll need to know what transceiver type or RF modulation scheme is being used. If this isn't on the data sheet then you will need to use some expensive test equipment to figure it out. For a beginner this isn't a practical thing to do.

The quickest/simplest/easiest solution would be to disconnect the existing receiver and replace it with something that is Arduino friendly.

Agreed.

+1

6

Not in the FCC regulatory domain:

Unlicensed Part 15 Bands

Band Typical Use

160 - 190 kHz Hobbyist

510 - 1705 kHz Hobbyist

1.705 - 10 MHz General

13.553 - 13.567 MHz General

26.96 - 27.28 MHz Hobbyist, walkie-talkie, baby monitor, etc.

40.66 - 40.70 MHz Perimeter protection systems, control systems

43.71 - 44.49 MHz Cordless telephones

46.60 - 46.98 MHz Cordless telephones

48.75 - 49.51 MHz Cordless telephones

49.66 - 50.0 MHz Cordless telephones, walkie-talkie, baby monitor, etc.

72.0 - 73.0 MHz Auditory assistance devices

74.6 - 74.8 MHz "

75.2 - 76.0 MHz "

88.0 - 108.0 MHz Hobbyist, miscellaneous

174.0 - 216.0 MHz Biomedical telemetry on unused TV channels

890.0 - 940.0 MHz Measurement systems, Amateur

902.0 - 928.0 MHz Multiple Part 15 uses, Amateur

1.91 - 1.93 GHz Personal Communications Service (PCS)

2.39 - 2.4 GHz PCS, Amateur

2.435 - 2.465 GHz "

2.9 - 3.26 GHz Automatic vehicle identification systems (AVIS)

3.267 - 3.332 GHz AVIS, Amateur

3.339 - 3.3458 GHz AVIS, Amateur

3.358 - 3.6 GHz AVIS, Amateur

5.15 - 5.35 GHz Unlicensed National Infrastructure Devices (U-NII)

5.725 - 5.825 GHz U-NII, other unspecified uses

10.500 - 10.550 GHz Multiple Part 15 uses, amateur

24.075 - 24.175 GHz Multiple Part 15 uses, amateur

46.7 - 46.9 GHz Vehicular collision avoidance/radar systems

76.0 - 77.0 GHz Vehicular collision avoidance/radar systems, Amateur

7

And ALL of those depend on which ITU region the OP is in.

Paul

8

And stating Amatuer bands complicates things further, as you need to delve into the Amatuer regulations for a specific country to identify the exact purpose that you are permitted to use the allocation for.

In the UK for instance as a licenced Amatuer I have access to a host of frequencies ....... for Amateur radio purposes.

I cannot use the allocations to control my central heating.

9

In the FCC regulatory domain, Part 15 devices can share a band with amateurs, but you can't squeal if you get clobbered. or, you can, but so what.

except where I live. where I live amateurs can't use the 902-928 band, but Part 15 users can. So I just stay away from it because explaining it gives everyone a headache