Vector plotter with lasers

[Hubert] sent in his experiments using HDDs, CDROMs, speakers, and other components to make an XY laser plotter. Those carefully reading will note, its not all three to make one plotter, but rather three plotters each using a separate system. The setups have their advantages and disadvantages, and [Hubert] is sure to point them out; including circuit diagrams and pictures to help you on your own trials.

There is a little difficulty in reading English not so good, but considering we’ve never seen a single-laser vector plotter done before (spirographs come close, and no one wants to wait 85 seconds) it’s still very impressive.

[Thanks TJ]

Oscilloscope doubles as a serial terminal

PC-based USB oscilloscopes are fast becoming all the rage. [Matt Sarnoff’s] Terminalscope takes the reverse approach, adapting an oscilloscope into a full serial terminal. You may have seen something similar before in the Dutchtronix/SparkFun O-Clock, but [Matt’s] project goes one further by adding a PS/2 keyboard port for full bidirectional serial communication, and with much sharper display resolution to boot.

The mostly VT-100 compatible Terminalscope is built around two AVR microcontrollers: an ATmega328P runs full-tilt to generate the video signal and handle serial I/O, while an ATtiny45 handles keyboard input to avoid interrupting the ’328’s duties. Rather than vector trace each character, a raster-scanning approach is used: the beam follows a fixed X/Y path (like a television), while modulating the Z input (beam intensity) to form an image. The device can be connected to a PC via serial port or USB-to-TTY adapter, or directly to another microcontroller to debug serial output.

We recently showed an oscilloscope being used as a multichannel digital logic display. The Terminalscope provides yet another use for this essential bench tool and could nicely round out a “poor man’s” testing setup. The schematic and full source code are available for download.