Automating heating vents with openHAB, esp8266 and LEGO - Part 2.5; Hardware rework

Working with hardware is fun; working with LEGO hardware is awesome. So before proceeding with the next part of my heating vent automation series, I took the opportunity to refine my vent manipulator, with the following aims:

• Quieter operation; v1 sounded like a coffee-grinder
• Faster movement; to sound like a quieter coffee-grinder for less time
• Lower stack height above floor level; to avoid impeding the sofa-bed mechanism directly overhead

V1 Hardware

As a reminder, here's the first hardware revision featuring a LEGO Technic XL motor and an extremely over-engineered - and tall - chassis.

V2 Hardware

Here's the respun version, which works as well as, if not better than, the original.

The changes:

• The chassis is half as high above the vent surface
• The rack-and-pinion mechanism is centered in the chassis to reduce torque
• The rack is situated lower to reduce flex
• The motor is reduced in size to a LEGO Technic "M" motor (quieter and faster)
• The manipulator clamps to the vent with a Technic pulley wheel instead of a brick, further reducing height-above-floor

Now we're in a really good position to get down-and-dirty with some firmware...