How To Wire A Stepper Motor To The Arduino Conveniently

While working on my Braille display, one problem I encountered early on was motor connecting – simply put, how to connect the motors to the driver board so I could disconnect them easily. Since many driver boards have screw terminals, you’d think that’s as easy as it gets. However, try disconnecting two motors so as to redirect wires or move a motor; that means unscrewing as many as ten terminals. Plus, if you haven’t written down the order the wires … Continue reading

Endstops And Switches in the Braille Display (or CNC/Reprap Machines)

A little detail many CNC or 3D printer devices minimize is the endstop – what the device does when it runs out to its maximum travel. For the Audrey Braille device, I’ve been working with a photo sensor which detects when its infrared light beam is interrupted. As I mentioned recently, the device can be wired together using two resistors and three wires (power/ground/signal). Of course, the endstops for the Braille device are different than for a CNC device; for … Continue reading

Adding an Opto-Interruptor Part 3

As I’ve already discussed here and here, opto detectors are one way to sense position. Unlike a switch, there’s no moving parts, so reliability is high. However, the compromise is a more complicated setup. In a previous article, I showed a schematic that sent a signal to the Arduino when the light beam was unbroken between diode and sensor, and turned off when it was broken. One reader commented that the usual way was the reverse, and included a link … Continue reading

The Braille Display Movable Head

For Phase 2, I decided to change some of the details for the device. In particular, I didn’t like the flexibility of the Acrylic pieces, and needed something more solid – solid means faster motion, which means speed in updating. My solution was to create the head out of plates of acrylic, which are then bolted together. The result is much stiffer, much stronger, and therefore faster moving: Another change is the use of linear bearings for the motion (orange … Continue reading

Audrey Pankhurst, 1927-2008

Today marks the fourth anniversary of my mother passing. I find there isn’t much I can (or wish to) say here about my mother. She taught me to strive to be good, no matter what others try and do. She was a voracious reader (part of the reason I felt she should be the namesake of the Braille Reader/Refreshable Display). She was a kind person, and she is missed. Here’s a picture of her, taken about four years before the … Continue reading