Emil's Projects & Reviews

OpenHardware & OpenSource

Entries tagged "avr".

Graphic LCD display 28th August 2005

I've recently bought online a large quantity of displays and paid a very good price for the lot. The displays came "as is" with absolutely no documentation or hint from the web. The company that originally produced them was out of business and their website was gone. I hopped that I will be able to reverse engineer these displays and my work paid off.

LCD Front View

LCD Back View

This entry has been cut, click to read on.

3 comments. Tags: avr, graphic, lcd, reverse engineering.
I2C interface with a cheap PCI GPS 19th April 2013

This project describes how to make a small GPS module suitable for use with RC quadcopters and airplanes from an inexpensive laptop GPS.

This entry has been cut, click to read on.

1 comments. Tags: avr, gps, i2c, ublox.
Making a better HC-SR04 Echo Locator 22nd January 2014

I have bought several cheap echo location circuits from AliExpress and I'm planning to use them in one of my robotics projects.

HC-SR04 Front ViewHC-SR04 Back View

They are very cheap especially if you buy a dozen you can get them bellow 2$ shipped. Once they've arrived, to test them, I wrote a quick C test program for an AVR board which displays the distance in cm to an obstacle. The results were pretty accurate for as far as 3-4m distance for hard obstacles. Unfortunately when there are no obstacles in front of this detector or when the obstacles don't have hard surfaces then erroneous results are returned.

I wanted to understand why this was happening so the first step was to reverse the HC-SR04 module schematic.

This entry has been cut, click to read on.

207 comments. Tags: avr, hc-sr04, ultrasound.
RGB Matrix Clock 9th August 2014

This is an example of over-engineering: a clock with 4 microcontrollers! Three of these are ATmega368 which are part of a cheap development board the Colorduino. Each of these controls one third of the display namely one 8×8 RGB LED matrix. The synchronization and communication between these 4 microcontrollers will happen via a multi-master I2C bus. So far I've finished the case and I've written a simulator in GTK of the various display modes which you may download bellow.

Clock simulator
Linux versionWindows version
and GTK runtime
design file (QCAD)

This entry has been cut, click to read on.

2 comments. Tags: arduino, avr, clock, i2c, rgb.

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