So a new Arduino arrived today after the connectors gave out on my older ones. It’s a cheap UNO clone and will be followed by a selection of Nano’s for various coming projects. I added support to my ESP8266 project for lightsOn, lightsOff, and setting a value for the lights on. Which can be found in the github repo. The server responds with a simple JSON string explaining the current state of the light, and can be adjusted by sending particular HTTP requests. Continue reading →
I’ve been busying myself with fixing up and adapting the RFM12B Linux driver. My first thought was simply to give people support for sending and listening for OOK signals as an extension, then taking the device support in the rtl_433 decoder to extend RFM12B driver to include lots of OOK device support for things like weather stations and energy monitors.
JeeLib already does most of this work on Arduino so for the most part this is simply a matter of joining lots and lots of code together from different places and making sure it sits right. I’ve decided that in order to do this it would probably be better to re-write the driver while trying to fix some of the original driver’s TODO list along the way.
The driver will loosely allow :-
- Compatibility with the original RFM12B driver & original JeeLib compatibility.
- Send OOK, FSK messages to devices.
- Listen for OOK, FSK messages from devices.
- Set tuning to a specific frequency.
Fitted the Salus RT500RF today, this wasn’t such a difficult job but I did blow two fuses following bad advice. The wiring of my Vaillant Turbomax doesn’t require bridging the COM and Live as suggested in many online videos, nor do I need to add a LOAD resistor between pins 4 and 5 on the boiler.
Here’s a simple diagram to demonstrate how to connect the Salus RT500RF to a Vaillant. Now simply when pins 3 & 4 of the Vaillant are bridged they will start the boiler up. An optional pipe thermostat to switch the boiler off if the pipe overheats can be inserted in between pins 3 on the Vaillant and N/O on the Salus RT500RF.
Now I’m getting ready to start sniffing the airwaves with my SDR and my RFM12B to see what I can do. All I really want is to set/get the current state of the boiler.
I’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.
So it seems that since the Arduino WiFi module was a complete failure in the teasmade (well not complete, just unreliable and who wants their tea to be unreliable). I ordered a couple of ESP8266‘s. These are quite a hot topic at the moment, basically it’s just a serial port over wifi.
The intention is to control my book case lighting with them, so I want to do a few things while testing. Firstly the initial concept is to be able to send a RESTful command to turn a light on/off, Simple enough. Second I want to be able to send a value and have the lights set to that value e.g. 255 which will set the brightness. Third, I want to be able to have the ESP8266 send a RESTful command to a php test server elsewhere on the network. Finally, I want to be able to send a “status” message in JSON on request. Continue reading →
Thanks to impshum digging around with epic google foo I found the correct GPIO_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.
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.
I thought I’d put down a little list of my top 10 things I do with my Arduino boards at home. I’ve been experimenting a lot with ambient circuits, up cycling and things like that so you could say that these things are skewed towards that kind of thing.
- Ultrasonic Sensors – be careful with these, I bought a pack of 4 from a dodgy supplier and the MAX232 chips had a bug which causes them to overheat rapidly and they get hot enough to burn stuff. You can use these in a lot of things, I’m currently using two as the eyes for a small robot I built to keep the cat occupied.
- PIR Sensors – these are cheap and cheerful little blighters. Ambient circuits usually require some kind of human interaction, so ultrasonic and PIR are both decent ways to do that. Depending on how you direct them and mix them they can become quite an human interaction tool.
- Bluetooth HC-06 – With speeds up to 250kbps the HC-06 is perfect for fast remote serial ports which can be accessed easily from a computer or android device. The HC-06 unlike the HC-05 is reprogrammable, you can hack it in various ways messing with it’s internal setup for the serial port. This is the fastest and easiest way to add a radio to a remote device that I’ve found, and I’ve tried NRF24’s, RF12’s, Wifi shields and other means. These are certainly in the category of just works(tm).
- WS2811 RGB LED Strip – Unlike the 2801 the 2811 has individually addressable LED units, whereas the 2801 has 2 LEDs per controller. It works well with the FastLED library and lets you separate the LEDs onto individual faces of a 3D shape. They’re also significantly cheaper than BlinkM’s are and much easier to obtain in large quantities.
- Gyroscope – If your project has any moving parts, it’s a good idea to put an accelerometer in there, it can give you feedback in interesting ways. Very useful to have on around.
- MSGEQ7 – With no particularly easy way to say it, it’s an equaliser IC this little chip will take a sample of audio and tell you the value of it on 7 different frequency bands. It’s useful for doing things like defining colours to be illuminated in time with music and things of that nature. Microphones will need a little amplifier to get them working but it’s a genius little chip.
- DHT11 – Another favourite of mine is the DHT11, temperature and humidity. You can connect these up to one of these mini arduino+rfm12b boards and you’ve got a thermometer and humidity sensor anywhere.
- RFID Kit – This cheap and cheerful RFID kit can be used in all kinds of ways, creating proximity based installations or interactive spaces where each object in the space has it’s own unique ID.
- Motor shield – There are tonnes of motors laying to waste because they’re not re-used, I collect them up and put them to work when I need one so a motor shield is always useful to have. Obviously you can always bang something together with a few transistors, but a decent motor shield for testing is always handy.
- Screw shield – always handy to have around a screw shield can save a lot of time when prototyping.
To get what I need out of my 3D printer it was clear that the Gen7 although a great board to build was not going to be suitable for every day use.
I got myself a RAMPS and assorted add-on boards:
- RAMPS 1.4 shield & Arduino Mega
- LCD, SD & Click encoder combo
- Lots of new wiring
- An EEPROM
- Bluetooth HC-06 module (already had this)