Sliding Greenhouse door opening and closing mechanism

prusaprinters

This is a proof of concept installation. Based onhttps://www.thingiverse.com/thing:3878385 I've modified the rack so that it fitted in a slot on my greenhouse door, and was able to clear the frame when the door was opened and closed.I bolted 2 of these next to each other in that slot. To get the heads of the bolts flush in the plastic I simply used a screwdriver bit in an electric drill and rotated it at high speed, the friction was sufficient to melt the plastic so the head could be sunk, and the teeth were unaffected by this.I then modified the original pinion gear of the source model so it would fit on the shaft of a 5rpm high torque electric motor (D shaped pin).I will be wiring this up to an ESP8266 and a L298N H bridge to allow remote opening and closing of the door based on temperature and humidity, as my greenhouse overheats even when the window is wide open.The reason for having the pinion only half geared is that I I have a hole for a magnet in it, and will be having a hall effect sensor detect when the teeth are disengaged - this will be the standard parking position for me, this allows for the door to be opened and closed when the mechanism isn't in use (the engaged teeth would have locked the door).I will be fitting sensors to prevent opening and closing too far.CautionYou should fit a sensor to detect an obstacle in the path of the door to prevent a crushing injury.In my installation I imagine that the teeth or motor shaft will jump or strip, or the motor stall if it meets anything - but this should not be relied upon as a safety mechanism.I have a kill switch fitted on mine in case of problems.Finally - it is possible to leave the door in a closed position with the teeth engaged, if you are inside the greenhouse you could be locked in! In that case the drive pinion gear can be slide off the shaft to allow door opening (don't ask me why I'm mentioning this).Print SettingsPrinter Brand:CrealityPrinter: CR-10Rafts:NoSupports: NoResolution:0.2mmInfill: 15%Filament: Generic PLA  Notes: I printed with 4 perimeters just to make the teeth tough.   Category: Outdoor & Garden