Move the blinds up and down

Design principles

  • Control the blind motors.
  • React immediately on the two buttons.
  • The relais shall be connected in a fail-proof way: in series. The first relais switches the motor on or off, the second relais chooses which motor runs.
  • No need for interrupts and sleep mode (since we are mains powered and for simplicity). Hence we can also be repeater.
  • There are two mechanical buttons combined in 3 stable positions: up, down or idle. These are mounted on the wall next to the blinds.
  • No remote controlled movements while the buttons are in up or down state, only when idle.
  • If a motor runs, then after a timeout, the relais shall fall off. Measurement revealed that timeout of 20s was not sufficient to move the blinds completely up - so the timeout is set to 30s.
  • If a motor is running thanks to a remote command, changing one of the switch positions by hand shall stop the motor immediately for safety of operation (not yet implemented).
  • If a motor has been running and then stopped, you can not start it again unless a few seconds (4) later. This to prevent damaging the relais. This happened to me with the first implementation.
  • The software should protect the relais contacts from burning in or fusing by preventing to be switched on multiple times too short after each other.

Used components

Future extensions

  • Protect the relays against surges due to the inductive load with a varistor.
  • Protect the relays against surges due to the inductive load by prohibiting manual operation during a short period (1s?) after switching the motor off.
  • Measure current to be safe (not implemented yet)
  • AC current measurement can be done in software, since no accuracy is needed (not implemented yet)
  • Current sensor: CurrentMeasure5A
  • If the buttons are pressed, the relais shall switch on and the motor runs. After a while, the motor current drops to zero, and the relais shall switch off (so that it does not keep drawing power). (not implemented yet)
  • If the motor current does not drop to zero after a timeout, the relais shall still fall off after the timeout.

Behaviour

BMStatechart.svg

States

State Constraints Description
idle   the motor is not running
button up

entry: run the motor up

after 30s: trigger timeout

the motor is going up thanks to pressing a button
button down

entry: run the motor down

after 30s: trigger timeout

the motor is going down thanks to pressing a button
wait

after 4s: trigger toggleTimeout

entry: stop the motors

delay to prevent damage to the relais

the motors should not be stopped and started too fast too many times - this burns out the relais contacts

remote up

entry: run the motor up

after 30s: trigger timeout

the motor is going up thanks to a remote command
remote down

entry: run the motor down

after 30s: trigger timeout

the motor is going down thanks to a remote command
up entry: stop the motors the blinds are completely up
down entry: stop the motors the blinds are completely down
unknown entry: stop the motors

the motor is not running

we do not know what the position of the blinds is

Actions

Action Validations Effect Description
buttonPressedUp not accepted when the state == up   the up button is depressed
buttonPressedDown not accepted when the state == down   the down button is depressed
buttonReleasedUp     the up button is released
buttonReleasedDown     the down button is released
timeout     after a minute, we give up
remoteUp

not state up

no buttons pressed

  a command has been received from remote for up
remoteDown

not state down

no buttons pressed

  a command has been received from remote for down
interrupt    

while moving automatically, someone presses a button

this serves as an emergency stop

remoteStop    

while moving automatically, a remote STOP command is given

this serves as an emergency stop

toggleTimeout     after a few seconds, it is safe to start a next action

Wiring

BlindsModule_bb.png

MISO = M1 MOSI = M0

Component Pin Wire Pin Component
NRF24L01+ Adapter VCC red 5V PowerSupply HLK-PM01
NRF24L01+ Adapter GND black GND PowerSupply HLK-PM01
NRF24L01+ Adapter CE white D9 ArduinoNano5V
NRF24L01+ Adapter CSN orange D10 ArduinoNano5V
NRF24L01+ Adapter SCK grey D13 ArduinoNano5V
NRF24L01+ Adapter M0 (MOSI) yellow D11 ArduinoNano5V
NRF24L01+ Adapter M1 (MISO) purple D12 ArduinoNano5V
ArduinoNano5V 5V red 5V PowerSupply HLK-PM01
ArduinoNano5V GND black GND PowerSupply HLK-PM01
RelayModule2Channel 5V red 5V PowerSupply HLK-PM01
RelayModule2Channel GND black GND PowerSupply HLK-PM01
RelayModule2Channel In1 green D7 ArduinoNano5V
RelayModule2Channel In2 blue D8 ArduinoNano5V
Button 1   orange D2 ArduinoNano5V
Button 2   purple D3 ArduinoNano5V

Safety

safety.png

Protection with inductive load

It is advised to use a Varistor over the contacts of the relay.

See https://www.ia.omron.com/support/faq/answer/36/faq02804/

Source Code

Based on https://www.mysensors.org/build/relay

Code at: blindsmodule

Programming

  • Board: Arduino Nano
  • Processor: ATmega328P (Old Bootloader)

Rework: Blinds Module V2

After a few years, I reworked this module according the following complete schematics, and made a custom PCB for it:

BMV2.png
BC547.jpg

Using Platformio

Also: using Platformio for building:

pio run -t upload -t monitor

The file platformio.ini contains:

[platformio]
src_dir = blindsmodule

[env:uno]
platform = atmelavr
;board = nanoatmega328new  <-- the board I use has an old bootloader, so this does not work!
board = nanoatmega328
framework = arduino
monitor_speed = 115200
lib_deps =
    548  ; MySensors
    thomasfredericks/Bounce2

PCB design

Designed with KiCAD.

foto/PCB.png

Screenshot of the PCB in KiCAD

foto/P4170003.JPG

Testing the physical layout with a printout of the silkscreen and a piece of styrofoam EPS (expanded polystyrene foam)

How to solder a thermal fuse

P4280003.jpg

Keep the thermal fuse submerged in a glass of water!

The assembled board

P4280010.jpg

The Arduino and the radio still need to be plugged in

Software

First sign of life on the Domoticz log:

2022-04-29 11:35:02.470 MySensors-Gateway-LAN-W5100: Blinds (Blinds Module 2)
2022-04-29 11:35:02.449 Status: MySensors-Gateway-LAN-W5100: Node: 14, Sketch Name: Blinds 2
2022-04-29 11:35:02.457 Status: MySensors-Gateway-LAN-W5100: Node: 14, Sketch Version: 2.0

And on the terminal (ID 14 was already administered):

__  __       ____
|  \/  |_   _/ ___|  ___ _ __  ___  ___  _ __ ___
| |\/| | | | \___ \ / _ \ `_ \/ __|/ _ \| `__/ __|
| |  | | |_| |___| |  __/ | | \__ \  _  | |  \__ \
|_|  |_|\__, |____/ \___|_| |_|___/\___/|_|  |___/
        |___/                      2.3.2

16 MCO:BGN:INIT REPEATER,CP=RNNRA---,FQ=16,REL=255,VER=2.3.2
27 MCO:BGN:BFR
28 TSM:INIT
29 TSF:WUR:MS=0
36 TSM:INIT:TSP OK
38 TSF:SID:OK,ID=14
39 TSM:FPAR
44 ?TSF:MSG:SEND,14-14-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
293 TSF:MSG:READ,0-0-14,s=255,c=3,t=8,pt=1,l=1,sg=0:0
297 TSF:MSG:FPAR OK,ID=0,D=1
335 TSF:MSG:READ,7-7-14,s=255,c=3,t=8,pt=1,l=1,sg=0:1
462 TSF:MSG:READ,17-17-14,s=255,c=3,t=8,pt=1,l=1,sg=0:1
892 TSF:MSG:READ,20-20-14,s=255,c=3,t=8,pt=1,l=1,sg=0:1
2052 TSM:FPAR:OK
2053 TSM:ID
2054 TSM:ID:OK
2056 TSM:UPL
2061 TSF:MSG:SEND,14-14-0-0,s=255,c=3,t=24,pt=1,l=1,sg=0,ft=0,st=OK:1
2069 TSF:MSG:READ,0-0-14,s=255,c=3,t=25,pt=1,l=1,sg=0:1
2074 TSF:MSG:PONG RECV,HP=1
2076 TSM:UPL:OK
2078 TSM:READY:ID=14,PAR=0,DIS=1
2085 TSF:MSG:SEND,14-14-0-0,s=255,c=3,t=15,pt=6,l=2,sg=0,ft=0,st=OK:0100
2093 TSF:MSG:READ,0-0-14,s=255,c=3,t=15,pt=6,l=2,sg=0:0100
2100 TSF:MSG:SEND,14-14-0-0,s=255,c=0,t=18,pt=0,l=5,sg=0,ft=0,st=OK:2.3.2
2110 TSF:MSG:SEND,14-14-0-0,s=255,c=3,t=6,pt=1,l=1,sg=0,ft=0,st=OK:0
2124 TSF:MSG:READ,0-0-14,s=255,c=3,t=6,pt=0,l=1,sg=0:M
2131 TSF:MSG:SEND,14-14-0-0,s=255,c=3,t=11,pt=0,l=8,sg=0,ft=0,st=OK:Blinds 2
2143 TSF:MSG:SEND,14-14-0-0,s=255,c=3,t=12,pt=0,l=3,sg=0,ft=0,st=OK:2.0
2154 TSF:MSG:SEND,14-14-0-0,s=1,c=0,t=5,pt=0,l=15,sg=0,ft=0,st=OK:Blinds Module 2
2162 MCO:REG:REQ
2167 TSF:MSG:SEND,14-14-0-0,s=255,c=3,t=26,pt=1,l=1,sg=0,ft=0,st=OK:2
2174 TSF:MSG:READ,0-0-14,s=255,c=3,t=27,pt=1,l=1,sg=0:1
2180 MCO:PIM:NODE REG=1
2182 MCO:BGN:STP
Blinds 2 2.0 - Online!
Initial state is: unknown (0).
Tags: domotica nodes
Comments: