Category Archives: Electronics

USB Controller for 12 RC Servos

Posted on August 12, 2010 by Andreas Goelzer

This article describes building a small (3.3 cm times 3.3 cm) RC servo controller using an avr microprocessor and an FT232RL USB-uart chip. All RC servo signals can be set to pulsewidths from 0 to 8.1 ms using the usb-serial interface.

RC Servos are popular among modelling and robotics enthusiasts because of their simplicity. They take a pulsewidth-encoded input, and turn accordingly with relatively high torque. They have their disadvantages, for example one cannot tell if the servo was able to get where it was sent, but their low price and the fact that driver and gear box are integrated make up for that. Also, Conrad sells them for 3 € a piece, so I bought some.

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lcdshift

Posted on March 31, 2009 by Andreas Goelzer

LCD Controllers using an HD44780 Display Controller are commonly used for small batch electronic devices, and are popular with electronics fans worldwide. One problem with those controllers is their demand for IO-lines, due too the parallel interface they require at least 7 IO lines.

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Blinking Eva

Posted on December 6, 2008 by Andreas Goelzer

Since it’s suddenly, out of nowhere, christmas time again, and since christmas is traditionally the time to build blinking somethings, i decided to publish this. Long ago – well, actually last year – this as a christmas present for my girlfriend Eva.

What does it do? Nothing useful. You plug it in, and the various LEDs blink wildly, one letter at a time, two letters at a time, all on, all off.

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usbmot

Posted on November 3, 2008 by Andreas Goelzer


This device connects to a computer’s usb port and controls two small electric motors using the L293D. The atmega microcontroller uses the firmware-only USB driver from objective development.

Device description

The usbmot device controls up to two small motors, 600 mA current each, 1.2 A peak each, with an atmel atmega microcontroller connected to some host device via USB. The speed of the motors can be controlled with PWM.

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