Temporary Motorised Blinds (MQTT controlled)

thingiverse

This is a custom motor housing for a high-torque geared motor. I designed it with a mounting bracket so the motorized blinds can be easily removed or added as needed, such as only using them when away. When I next redecorate, I may install a permanent 12V power supply, which would mean the XT60 connector could be omitted. Required components: 1 x high-torque geared motor (I used 5 rpm, it's slow but will never have problems with moving my blinds) 1 x L298N motor controller 1 x ESP8266 (I used a Wemos D1 Mini) 1 x micro-switch A couple of 3mm screws for the motor and 2 wood screws for the bracket Print each component - I suggest using the orientation given - you will need support material, but not much. I'm not providing wiring details or software, as there are many tutorials available, but I'll mention how I assembled this: Solder the motor and micro-switch together. First, glue the microswitch to the body with epoxy. It can be held in place from the top by hand while the glue sets. The micro-switch is a failsafe that prevents the motor from powering past the closed position. The micro-switch is wired so power normally goes through it when it's open. If it powered past the end stop, the whole motor assembly would "climb" the blind chord and perhaps snap it. The micro-switch needs to be resting just over the end of the bracket, so that if the motor climbs the chord, the micro-switch will hit the bracket and will be depressed, cutting power to the motor and preventing damage. Pass the motor into the body from the top and fix in place with 2 screws. Press the blind gear onto the gearbox shaft; it should be tight. I added some epoxy just to be sure and made sure it was square before the glue set. Connect the motor wires to the number one L298N motor output. Connect an XT60 connector (12V supply) to the L298N supply input, then glue the connector in place. Connect a Wemos D1 mini to the 5V output from the L298N and ground. Connect 2 pins from the Wemos D1 mini to IN1 and IN2. Slide the L298N into the body heatsink towards the motor. I uploaded my Wemos D1 mini with code that allows it to respond to MQTT commands. I also recorded the present state of the blind using SPIFFS, so that in the event of a power outage, the blinds could not be closed more than once. Test your device. Glue the top and bottom to the body - I used CA and kicker. Hang the assembled blind controller, with the body protruding above the bracket, and with the micro-switch open but against the body of the bracket. Gravity and elastic bands can be used to tension the system; if it over-torques, the body will climb, depressing the micro-switch which will cut power. Caution - there is a big heat sink on the L298N. I don't imagine that this will get hot in normal use as the motor will only run for a few seconds at a time. You should take precautions to prevent it from getting too hot, such as thermal cutouts or fuses. Ensure all electrical components are insulated. My home automation system only powers my blind controllers while they are moving the blinds (a few seconds); you may choose to do likewise.