The most ridulous wall clock ever...
This page was featured on hackaday.com on 18-June-2006. Yay. Google Pages has decided though that we're using too much bandwidth.
I wanted a simple application to test my pusle width modulator/servo controller circuit, and so I built a robotic arm with two degrees of freedom.
- Photo from side [mirrors: Andy/Seanet 1, MB 1, H3PO 1, flickr].
- Photo from above [mirrors: Andy/Seanet 2, MB 2, H3PO 2, flickr].
I used cheap ten dollar servos, and took a jigsaw to scrap wood for the mechanics. To check the accuracy of it, I fastened a cheap laser pointer onto the arm, and wrote some software to control it. This will ultimately lead into my sentry gun project.
To test the repeatability of the positioning, I made a poster on the wall with 14 circles: "Hour", "Minute", "AM", "PM" and the digits zero through nine. I calibrated the arm to point the laser pointer at each of these circles by manually moving until the laser pointer was right, and then recording the positions.
I then wrote a simple program (clock.tar.bz2) on my laptop to send the right signals down the parallel port, and blazao, it tells time.
Since it can only illuminate one figure at a time, I programed to point to each of the figures in a sequence. For 3:24 pm, it points to: "Hour", 3, "PM", "Minute" 2, 4. It spends one second on each figure, and then moves on, and loops at the end. The servo motors even make a nice ticking noise once a second. Here is a 4 MiB video in mpg; sorry it's rotated 90 degrees. [mirrors: Andy/Seanet, MB, H3PO, youtube].