Description:

This is a Mysensors replica of the Livolo EU Switch(2 channels 1 way) front plate for the VL-C702X-2_Ver_C1 Livolo hw revision.

Key Features:

1. Capacitive touch sensing using MTCH105 specialized IC(using guard rings also for better noise immunity), touch sensitivity can be adjusted now from code
2. MySensors or BLE ready(NRF51822) - PTR5518
3. DC-DC Buck converter for powering from the 12V line ( the DC-DC converter can be bypassed and not used at all if desired by soldering the 3V_EN jumper and removing the L1 ferrite bead or by not soldering the dc-dc converter components)

Work progress:

1. Test/verify the pcb board correctness(from both electrical and mechanical point of views) - DONE
2. Produce the initial PCB's using some external PCB manufacturer - DONE
3. Components assembly(soldering) - DONE
4. Create Mysensors sketch code - DONE
5. Verify the real board with running code - DONE

Firmware programming and testing steps for MySensors:

1. Install Arduino IDE
2. Install nrf5 arduino core from here: https://github.com/sandeepmistry/arduino-nRF5
3. Select the nrf51 generic board (16K ram and 256K flash) variant(or nrf52 generic if you have a nrf52832 device)
4. The low frequency oscillator needs to be set to RC oscillator in the Arduino menu
5. NO Softdevice needs to be selected
6. Use a st-link v2 programmer
7. You need to connect only: SWD, SWCLK, Vdd and GND
8. Load your MySensors sketch or use the one provided with this project

Firmware programming and testing steps for BLE:

1. Install Arduino IDE
2. Install nrf5 arduino core from here: https://github.com/sandeepmistry/arduino-nRF5
3. install Arduino ble peripheral library from here: https://github.com/sandeepmistry/arduino-BLEPeripheral
4. Install the required softdevice as explained here: https://github.com/sandeepmistry/arduino-nRF5#selecting-a-softdevice
5. Select the nrf51 generic board (16K ram and 256K flash) variant(or nrf52 generic if you have a nrf52832 device)
6. The low frequency oscillator needs to be set to RC oscillator in the Arduino menu
7. Select S130 softdevice from menu if you have nrf51(or S132 if you have nrf52)
8. Use a st-link v2 programmer
9. You need to connect only: SWD, SWCLK, Vdd and GND
10. Load my BLE testing sketch, compile and upload
11. Use the nrf connect tool for Android: https://play.google.com/store/apps/details?id=no.nordicsemi.android.mcp&hl=en
12. Scan for available devices - you should see a "Livolo" device
13. Connect to it
14. After connecting and characteristics discovery -> expand one of the "unknown characteristic"(there's one for each livolo channel or relay)
15. Use the button with an UP arrow on it to send values - select UINT8 - send 1 for turning ON the light, send 0 for turning OFF the light for the selected channel

Extra steps needed for the Livolo power supply/relays board!!!

1. The R3 resistor(marked with 104 - 100Kohm) near the bridge rectifier needs to be replaced with a 1Kohm one(1206 package)
2. The R13 SMD resistor needs to be replaced with a solder bridge
3. Mount a X2 capacitor of 1uF - 2.2uF rated at a minimum of 275Vac directly on the light bulb(in parallel)

Notes:

• If using BLE based firmware with this board the current consumption on average is only 5mA **for the **WHOLE BOARD(including leds) and this is constant over time
• If using MySensors firmware instead the current consumption on average increases to **18-20mA **which is 4 times bigger than BLE
• What I noticed is that the original Livolo power supply(the one used in stand-by mode) is designed to work with currents of 1mA or even below so that's why the above hardware modifications(the extra steps) need to be performed - otherwise the switch won't start
• It's not advised to replace the R3 resistor with a bridge only as the stand-by power supply may be damaged over time and it's required that the custom top board(for which the current project was made for) to draw a lower current as much as possible(ideally would be several milliamps and even lower but it works with 10-20mA also)

Practical usage ideas:

• Currently(and based on my previous experience with this kind of project) I will use all the Livolo switches preloaded with BLE firmware because of the lower current consumption AND in each room there will be a BLE Central node(based on Raspberry PI Zero W) - see this project: RFM69W Raspberry PI Zero(W) Shield(HAT) which will route messages to/from the Livolo switches BLE Peripherals to the MySensors network.

HW Revisions:

• 0.1 - initial hw design
• 0.2 - switched to MTCH105 touch sensor
• 0.3 - added 3V line jumper

Credits: All credits go to MySensors team for the great work and to the opensource community