“I spent way too much time and money on this project but I am still happy with the result. One reason that it took me so long is a major mistake in the electronics design which I only realized rather late the other is that many of the mechanics are on the edge of what you can achieve with consumer FDM printers in terms of tolerancing and friction.
The clock is driven by 64 magnetic actuators based on PCB coils. It has 2 mm travel and is latching in both positions, i.e. power only needs to be applied when switching positions.
There are two other projects which inspired me to do this, first I saw a video of this 192px haptic display built by researchers from Switzerland to help blind people. The other is the mechanical 7-segment display made by indoorgeek. From the Swiss haptic display, I was able to get a lot of useful information on the technical design by reading their publications and patents. My first intention was to make an 8x8 haptic display for displaying weather icons or to play classic games like snake and Arkanoid the idea of making a word clock only came later.
Supplies:
Parts
- 64 pcs NdFeB N45 magnets, diameter 4 mm, height 4 mm
- 64 pcs NdFeB magnet, diameter 1.5 mm, height 7 mm
- 1 pc self-adhesive ferrite foil, 60 x 60 x 0.1 mm
- 4 pcs M3 screws, 30 mm long + nuts
- 2 pcs custom PCB with coil matrix (see below)
- 1 pc custom driver PCB (see below)
Tools
- SMD soldering equipment
- a decent 3D printer
- hole punch pliers”