The indoor plants in my livingroom were not getting enough sunlight because of the desire to keep the blinds closed at night, and the desire not to have to wake up at sunrise to open them. To solve this problem, I hooked up a bit of hardware to the blinds to allow the computer to open and close them. This consisted of a gear motor that was designed to stop only at full rotation (a pulse on the input would cause the output gear to make one revolution), and a DPDT relay to reverse the motor direction.

The trickiest part of the hardware was finding a way to attach the drive to the blinds. A piece of wood is epoxied onto the final gear, with pegs and notches to reinforce the connection (an earlier version scupley connector cracked). A slot in the wood fits over the attachment in the blinds used to control the tilt. The whole assembly is bolted to a piece of metal, which is bent to the appropriate angle and hooked over the top of the blinds. Although this alignment isn't perfect, there is enough leniency in the connections to allow it to rotate easily.

The software piece of this is relatively simple. A module allows python to send signals to the parallel port, so pulses of appropriate length can be sent to turn the motor one rotation forward or backward. The website is polled daily to get current sunrise and sunset times, and a schedule is set up to tilt the blinds accordingly at appropriate times. The python program also listens for http requests (so it can run without intrusion in the background, but can be accessed easily) to check for current state, and allow someone to change the blinds at any time.

the controller assemblythe installation setup

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