Upgrades… Salus RT500RF 868MHz wireless boiler control

RT500RFI’ve just received a Salus RT500RF in the post. I’m pretty much all prepared to hack this thing, at first I’ll sniff the airwaves with the RTL-SDR and try and get a handle on how it works. There’s been at least one blog article regarding this unit so I’ll also have a dig around them and see what they can tell me too. The idea is to get the Raspberry Pi with the 868MHz RFM12B to send a signal to turn the heating system on/off, and if possible, interrogate the current state of the boiler.

This will be the first stage in smartening up the house. The OWL CM160 and the Salus RT500RF are the first devices that I’m going to mess with as they’re the most useful to me right away. Next I’ll be turning my hand to Oregon Scientific weather sensors, Wireless door bells and other hardware on the 433/868 bands. These bands of course are used in Europe and some other locations, the equivalent is 315/915 for the US. So if you’re following my work then make sure you pick up the right bands for your location. It’s always best to buy radio transmitters and receivers in your own country because the likelihood of anything being on sale which isn’t allowed is reduced.

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RFM12B-Linux on the Raspberry Pi B2 – GPIO_BASE

Thanks to impshum digging around with epic google foo I found the correct PI B2 GPIO_BASEGPIO_BASE for the Raspberry Pi B2. Raspberry Pi used to have a peripheral base address of 0x20000000 now it’s 0x37000000 on the B2, so the GPIO peripheral address is 0x37200000 which has broken the odd GPIO based product (including the HotPi). I’ve added a pull request to RFM12B-Linux and that should be that. I still need to merge in changes for OOK and see if that works and of course, figure out how to set the frequency to listen/transmit on.

RFM12B’s will soon become a must add hardware to the Raspberry Pi, I just need to get that software working :). It’s a great piece of kit, and the code already in github is a good jumping off point. I’ve merged in a OOK sender fork, and I’ll be adding code to put the device into OOK listen mode. All of this controlled via ioctl. Essentially with the little RFM12B’s hooked directly into the Raspberry Pi GPIO port’s SPI pins you’ll have the ability to mess with anything out there, which uses 433/434MHz or 315MHz if you’re in the US, or 915MHz or 868MHz whatever HopeRF board matches with your locations radio standards.

At present I’m looking at getting the OWL to work because I already understand most of that. Next I’ll be looking at getting RF light sockets, lightwaveRF devices, indoor/outdoor weather sensors and even doorbells into the supported devices list.

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RFM12B-Linux and OOK/ASK and Oregon Scientific v3 protocol

RFM12BThe Owl energy monitor uses OOK/ASK via the Oregon Scientific v3 protocol. It looks like I might have to hardware hack my RFM12Bs to work with this protocol according to this article… Not ideal.

Receiving OOKASK with a modified RFM12B – JeeLabs Café – JeeLabs . net.

Although it seems there’s a branch of RFM12B-Linux which can do OOK already. I’m not entirely sure how this is going to work out, but I’ll keep posting.

I found some problems with RFM12B Linux, specifically it doesn’t work at all on the Raspberry Pi B+ 2. I’ve created an issue for this but I might be able to fix it if I can get some tinkering time. In the mean time I’m testing things with the original model B.

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OWL CM160 Energy Monitor with RTL-SDR

OWL CM160I have an Owl energy monitor model CM160, which has been mostly just acting as a real time monitor. In order to really USE the device I’m going to need to connect it to one of my running computers. At first I was using Eagle OWL on github. However it requires me keeping the LCD receiver and I want to eventually get rid of that, mostly because the only useful thing about it, the thermometer isn’t accessible over USB.

I decided that I should start experimenting around the 434MHz band with my SDR’s and see what I could come up with. Continue reading →