Stack Trace From The 1950s Punches Again

This repair/tutorial video by the telephone Connections Museum of Seattle features an amazing piece of electro-mechanical technology from the 1950s — the 5XB trouble recorder. Museum volunteer Sarah the “Switch Witch” has a deep passion for old phone equipment, and gives an excellent description of the trouble recorder, the problems it solved, and how it works, and how they went about fixing it.

As central office switching became more complex and more dense, the manual methods of hunting down faults became unmanageable. Semi-automatic approaches using trouble lamps, but even that had its limits. This “stack trace”, which could have hundreds of indicators, had to be frozen while the technician recorded the status on a form. If another fault came along during this time, it was lost. The solution, using the available technology of the day, was a mind-boggling punched card apparatus that punches over a thousand bits of information when an switching error is detected or when various watchdog timers expire.

Continue reading “Stack Trace From The 1950s Punches Again”

Music-Loving BeagleBone

Robotic control can get very complicated when multiple actuators need to work in coordination with each other. A simple robotic arm will require each joint to be controlled in sequence to attain a particular position. The BeagleBone Blue comes armed with motor drivers, sensor inputs, and wireless and is built for robotics.

[Andy] has prepared a musical robot called the BeagleBone Blue Electro-Mechanical Glockenspiel using the single board computer. The hardware consists of eight servo motors each with a mallet stick attached to them. The motors themselves are mounted on 3D-printed brackets allowing them to be mounted at the correct height. The servos connect to the main board for position control, however, an external supply had to be used to supply the necessary current to all the motors.

The software side has programs to translate notes into servo positions as well as connect to a web brower via MQTT and websockets. The basic user interface is simple and has buttons to connect to and send the keystrokes. The code, as well as the OpenSCAD designs, can be downloaded from GitHub. Check out the video below for a demo.

This project could be extended to an autonomous robot that plays tunes from the Internet. We are reminded of the rock throwing glockenspiel which was pretty cool and hope there are some permutations to come from both. Continue reading “Music-Loving BeagleBone”