Hi here is my 2 channel dimmer project that I am working on. The project will fit a 70 mm in wall round box. There are still some things to consider in the design, but i expect that i will be making an order within the next 2 weeks for this prototypes.

If there is interest i can share more about the project

Just for the fun off it i bought a Biltema presence controlled LED lamp for 79 SEK ~9$ having in mind that i should be able to use the nice box and interior to build myself a "cheap" motion detector to add to mySensors project.
http://www.biltema.se/sv/Bygg/Belysning-och-lampor/LED/Narvarostyrd-minilampa-2000033627/

I started by opening the lid and remove the board. This was a little troublesome as i had to compress the battery connector to get it out of its position, but i managed.
After that i tested different ways of how to fit in the Arduion mini and the RF in to the box. Unfortunatly i could not get it in without making the PIR sensor board smaller. I just cut down the board at the near the GND connector.

After this i had cut off the VCC and the motion output so i had to fix that by soldering wires for VCC and motion output shown below. connected pin1 and 8 fixin the VCC. and solderded the Via hole to the testpoint to fix the motion output from pin 2. Also i needed to cut the track just right of C3 to disable the fotoresistor so that the sensor work also in daylight.

I assembled back the board. Also you will need to replace the LED with a 10k ohm resistor (to reduce the current when activating) and then connect the Arduino sensor input to the R3 right side. This should give an active low trigger pulse.

And then i placed the component as i see that they should fit.

Now comes the next step to wire the R Fboard to the Arduino and then connect the motion output to the input of the Arduino.
There might be some changes needed for setting up the right length of the pulses on the motion detector. I have to investigate which of the R's and C's just right to the detector that does this.

This is as how far i came today.

Hopefully this will be one of those projects i finish.

I will make updates on the progress

Hi all
Here is my first mysensors HW that i developed and also my first post. Not all functions are tested at the moment.
I started by analyzing the current thermostat on size and function. Then i took all the info and started working with it in designspark.

My plan is to use this with Openhab

Spec
-Should be able to open/close valve in Uponor system
-Should in the future be able to open the valve from 0-100% (Think i need to change valves for this)
-Should fit in the Wirsbo thermostat mechanics
-The system shall fall back to "old thermostat" function if the home automation stops working by using the knob setting
-The system shall be built as much as possible on cheap components that could be bought on for example ebay

Old System

New system
If only on/off function is requested then the MOC 3023 could be replaced by a a new one with zero crossing detection and then also the zero crossing detector can be omitted (IL250 in the schematic)

Schematic

Result
The HW fits in the old casing
Not all components are mounted at the moment as i have not received them yet, but the board have partial functions

First attempt to see how a box could look like
Diameter 56 mm 50 mmside to side

@hek Its more that i at this moment have not gone through the pros and cons of open hardware. And this is something i will read up on. So Im not saying that i will not share, but i need my time to go through it.

Now the code is tested against openhab2.0 after some work adding HVAC in the binding. Will make a pull request for the binding part soon

Hi all
I will try to answer your questions.

Q: what sort of switch would be on the wall?
For this design i would recommend that you use 230 V rated switch to control the dimmer. The output is still only 0V that you switch on and off. But the design is made in such a way that if you get short circuit on the capacitor in series in to the rectifier there can be 230 V on the input pins ( very unlikely because of other things will burn) but it can happen.

Q: How are you sure that this hardware circuit …….
Doing a little benchmark and understand how dimmers and switches from NEXA or similar are working. Actually I ripped them apart and found out that they were using transformer less designs. From that I Googled this and read up on the topic as well as discussed this with colleges of mine. I then changed some parts as the transformerless design would in simulation not give more than 10mA so I added the MAX 17552 circuit in between and set the input voltage to 24 V with the zener diode and by that I will be able to draw about 30 mA (starting current of the circuit that I tested is around 24 mA).
Q: I suspect this unit is going to be mounted in wall behind……..
Yes of course but just use it as the switch, what I mean is that don’t use at ordinary switch were 230 V is applied. The circuit is designed to just feel a logic zero on one of the inputs. ( just make sure that you read my first reply above for safety reasons)
Q: can we control Celling fan using this dimmer.
Should not be a problem as I have used Triacs that are made for inductive load (not tested though). But the fan should not consume more than 4A. I also have not tested from a heat perspective how much power I can have running in the system. It might be less than the 2 channels times 4A.

Finally new boards have arrived..

Assembly will start soon:)

2 boards completely assembled and working as expected. 3 more to go after ordering the missing components. Now some last fixes to the code so that memory can be wiped by pressing a button and also the check if connected to the home automation system if not a fallback should be initiated

First components added after a visit to the lab at work and some soldering under the microscope

@bjornhallberg The sensors are working fine and have been installed in my home for the last couple of years. Some optimisation needs to be done to the code, that i have not done. This is more connected to understanding when the mysensors network is in "range" as i want to fallback on the manual knob if the mysensor network is inactive for some reason or if i sell the house and the controller goes with me.

@hepal
Hi The thermostats use mysensors serial gateway to communicate with the openhab that runs on a raspberry Pi 2. I run openhab 2.0 but in the beginning i was running 1.7.x

The project does not work without neutral wire

No i have not tested any minimum loads at the moment, this is one of the next steps

HI @dexterbot
Here is the code for the openhab

Items
/* Thermostats /
/ Hall */
Number Hallway_Temperature "Temperature [%.1f]" <temperature> (Temperature, C_Hallway, gMS) { channel="mysensors:hvacThermostat:gateway:Hallway_Temperature:temp" }
Number Hallway_SetPoint "HVAC/Heater set point " <temperature> (gMS) { channel="mysensors:hvacThermostat:gateway:Hallway_SetPoint:hvac-setPoint-heat" }
String Hallway_FlowState "Mode of heater [%s]" <heating> (gMS) { channel="mysensors:hvacThermostat:gateway:Hallway_FlowState:hvac-flow-state" }
Number Hallway_KnobTempVar1 "Knob temperature [%.1f]" <temperature> (gMS) { channel="mysensors:hvacThermostat:gateway:Hallway_KnobTempVar1:var1" }
String Hallway_FlowMode "Running mode" <heating> (gMS) { channel="mysensors:hvacThermostat:gateway:Hallway_FlowMode:hvac-flow-mode" }
Number Hallway_HystLowVar3 "hyst low [%.1f]" <temperature> (gMS) { channel="mysensors:hvacThermostat:gateway:Hallway_HystLowVar3:var3" }
Number Hallway_HystHighVar4 "hyst high [%.1f]" <temperature> (gMS) { channel="mysensors:hvacThermostat:gateway:Hallway_HystHighVar4:var4" }
Number Hallway_UpdateTimeVar5 "update time (s) [%d s]" <clock> (gMS) { channel="mysensors:hvacThermostat:gateway:Hallway_UpdateTimeVar5:var5" }

Things
Bridge mysensors:bridge-ser:gateway [ serialPort="/dev/ttyUSB0", sendDelay=200, baudRate=115200, skipStartupCheck=true ] {
/** define things connected to that bridge here */
hvacThermostat Hallway_Temperature [nodeId="59", childId="0"]
hvacThermostat Hallway_SetPoint [nodeId="59", childId="0"]
hvacThermostat Hallway_FlowState [nodeId="59", childId="0"]
hvacThermostat Hallway_KnobTempVar1 [nodeId="59", childId="0"]
hvacThermostat Hallway_FlowMode [nodeId="59", childId="0"]
hvacThermostat Hallway_HystLowVar3 [nodeId="59", childId="0"]
hvacThermostat Hallway_HystHighVar4 [nodeId="59", childId="0"]
hvacThermostat Hallway_UpdateTimeVar5 [nodeId="59", childId="0"]
}
sitemap
Group label="Thermostats" icon="heating"{
Frame label="Hall"{
Text item=Hallway_Temperature
Text item=Hallway_FlowState label="State [%s]"
Setpoint item=Hallway_SetPoint label="Set point [%.1f]" icon="temperature" minValue="0.0" maxValue="32.0" step="0.1"
Text item=Hallway_KnobTempVar1 label="Knob temperature" //Knob temperature
Text item=Hallway_FlowMode //Running mode
Setpoint item=Hallway_HystLowVar3 label="Hysteresis L [%.1f]" minValue="0.0" maxValue="5.0" step="0.1"
Setpoint item=Hallway_HystHighVar4 label="Hysteresis H [%.1f]" minValue="0.0" maxValue="5.0" step="0.1"
Setpoint item=Hallway_UpdateTimeVar5 label="Update time (s) [%d]" minValue="1" maxValue="4096" step="1"
}
}

Hi Tomas
I have only replaced the thermostats not anything else in the system.
This thermostat is a replacement of my Cosy thermostat (art no 804661), but i think it should work also for the following article numbers (80466, 80465, 804651 and 80464). This thermostat only works as a on/off for the valve, I did not spend any time on the night temp function. I have connected the thermostat to a transformer unit (art no 80460) which in principle only converts 220 v to 24 V which is then connected to the thermostat. When the thermostat turns on it passes on the ~24 V signal to the valve.

I will upload a schematic to the project

Hi all
I have a problem when my raspberry pi and mysensors/openhab when i do a restart. The problems seems to be ralated to the serial gateway and that the openhab dont find it or has the wrong settings.

Openhab starts when i make a reboot

I checked the serial by typing
stty -F /dev/ttyUSB0
response was

Seems here that the baudrate is wrong as my settings in the things file is

What i did to make it work was just to change this to use baud 9600 and then back to baud = 115200
after this it looked like

And everything started to work nicely

Does anyone now what the cause of this is and also how to fix it?

And now everything is connected together.
I had to change some values on the resistors.
R6 = 10k and C4 = 10 nF gives 2.5 seconds ON time. I also changed the sensitivity from 4 s to 0.05 Seconds, I am considering changing this a bit to some greater value to increase the time some.

I also need to do some changes to the Arduino board as the on led is always on and i think i should remove the regulator to save some more power.

Just for the fun off it i bought a Biltema presence controlled LED lamp for 79 SEK ~9$ having in mind that i should be able to use the nice box and interior to build myself a "cheap" motion detector to add to mySensors project.
http://www.biltema.se/sv/Bygg/Belysning-och-lampor/LED/Narvarostyrd-minilampa-2000033627/

I started by opening the lid and remove the board. This was a little troublesome as i had to compress the battery connector to get it out of its position, but i managed.
After that i tested different ways of how to fit in the Arduion mini and the RF in to the box. Unfortunatly i could not get it in without making the PIR sensor board smaller. I just cut down the board at the near the GND connector.

After this i had cut off the VCC and the motion output so i had to fix that by soldering wires for VCC and motion output shown below. connected pin1 and 8 fixin the VCC. and solderded the Via hole to the testpoint to fix the motion output from pin 2. Also i needed to cut the track just right of C3 to disable the fotoresistor so that the sensor work also in daylight.

I assembled back the board. Also you will need to replace the LED with a 10k ohm resistor (to reduce the current when activating) and then connect the Arduino sensor input to the R3 right side. This should give an active low trigger pulse.

And then i placed the component as i see that they should fit.

Now comes the next step to wire the R Fboard to the Arduino and then connect the motion output to the input of the Arduino.
There might be some changes needed for setting up the right length of the pulses on the motion detector. I have to investigate which of the R's and C's just right to the detector that does this.

This is as how far i came today.

Hopefully this will be one of those projects i finish.

I will make updates on the progress

@Denke
I cant find V_PRESSURE connected to CHANNEL_BARO below, can that be the reason?