Electric window motors allow your home automation system to open and close your windows as required. This could be useful for opening windows to allow ventilation, or to make sure all windows are automatically closed and locked when you leave home.
I recently got my hands on some AXA electric window motors that include a LIN bus interface so they can be linked to a home automation system, but I’ve never used LIN before so I needed to learn a bit about how it works. I designed my own LIN interface module that allows me to connect my laptop to LIN devices and manually send messages, and the module also allows an Arduino to control the window motors.
Parts used
- The electric window motors are AXA Remote 2.0, which I bought from Digilock Australia.
- I used a Freetronics EtherMega Arduino-compatible board, which combines an Arduino Mega with onboard Ethernet and Power-over-Ethernet. You can use any Arduino you like, provided it has enough hardware UARTs.
- The LIN bus shield that I demonstrated in the video comes from some mysterious supplier in the Netherlands called MrX. I don’t know who designed it, but if you search for “HOME-LINBUS Arduino Shield” you may be able to find it on eBay or other places.
- The LIN Bus Serial Interface Module that I designed for this episode is now available from Freetronics: www.freetronics.com.au/linmod. Also, you can see all the design files at github.com/SuperHouse/LINMOD
- You can use any USB-to-serial converter to link the LIN Bus Serial Interface Module to your computer. I used a Freetronics USB-to-Serial Converter.
- The hardware watchdog is the Freetronics Watchdog Timer Module.
- The sensor is the Freetronics Temperature / Humidity Sensor.
Source code
Simple example that provides a menu and sends commands to a single LIN interface: AXARemoteSerialLinbus
More complex example which includes MQTT, DHCP, reading a MAC address ROM, 4 LIN interfaces, a watchdog timer, and a temperature / humidity sensor: AXAWindowMQTT
Instructions and explanation
More details to follow! I’ll update this after the video is ready.
Hi,
What motors/equipment are you using to control the Shades in the conservatory?
I’ve seen there is AXIS (Coming soon) and MOVEZ (Coming soon) but wanted to know which ones you used and I couldn’t see a post / reference to it elsewhere.
Thanks.
T
Gracie University! Represent!
Hello Jonathan,
I can see that on the LIN BUS CHIP you have chip select on them, why are you not using that to select the individual chip you want to communicate to, bridge all the serial TX and RX to an UNO RX and TX so that you can cut down the cost of the project. I see that you need CS to be connected to VCC, so connect the with pull down resistor to ground and then using a current limiting resistor you connect the CS to digital ports on the UNO and then select the CHIP to receive commands. if 12V is required on the CS then transistors can be used to drive that. I feel a MEGA is an over kill for this what do you think?
Yes, you’re absolutely correct. When I designed the LINMOD board it was just as a simple breakout to experiment with connecting to the motors, and I expected that I’d be able to use a single bus to communicate with all the motors with just one module. It was only after I began controlling a motor that I discovered I would need to use one module per motor.
I could hack the modules to use CS to select them individually. I also happen to make Mega type boards though so it’s not a problem using them 🙂
Hi. Can this be used to intercept the more modern cars that have the auto up/down?
I need to invert the passenger and driver commands ans the switches are using only three wires, and one is a lin wire.
I convert vehicles from left to right-hand drive.
Hi, i see that you power the axa by lin bus at 12vdc. Normally the axa is battery powered at 6vdc. So I gues there is a voltageregulator in the axa. Do you now the min/max voltage range to power the axa by Lin bus?
I am late to reply to this, but in case it helps others
The LIN Bus on the Axa window winder does use 8 to 12 volts via the RJ12 connector.
LIN Bus hass 12Volt signalling in it’s spec, though the Axa implementation does specifiy nominal 8volts on pin 1,6 and ground on 2,5 with the LIN Bus on 3,4. It will happily run with 12V though
The motor may internally convert this, though from my previous experience with earlier AXA window winders, they just run a bit slower on battery than with the external power supply.