A Motorized Light Bulb Changer for That Hard-to-Reach Chandelier!

Mattwach, of the Matt’s Electronics & RC YouTube channel, has a chandelier that came with the house that his family purchased over 10 years ago. While it’s a nice piece, it’s positioned at a second story level, shining mostly upwards so as to provide indirect lighting. This also means that a traditional changer-on-a-pole won’t work, and who really wants to drag a huge ladder through the house and move tables and such around for access?

An interesting feature of this house in relation to the chandelier, is that there's a second story walkway that could provide a good vantage point for bulb changes – if changer-poles worked at 90º. Matt designed just such a device, and though it might sound like a joke about engineers and changing a light bulb, as shown in the video below at about the 29 minute mark, it works quite well! He was able to swap out the whole chandelier to more efficient modern bulbs using it, saving a total of roughly 825 watts of power usage.

The setup is more or less an adapter for a changer pole, adding a motor that spins at 90º via 3D-printed parts designed in OpenSCAD. Controls-wise, the changer uses an ATtiny85 microcontroller to take in voltage signals from a Playstation-style analog stick, which it translates into PWM and directional outputs that are sent to an L293D motor driver. The code also includes a rail velocity setting to keep the motor from ramping up too quickly, likely a good idea for this sort of application.