Yet another car related project, this is the AVR J1850 VPW Interface which was designed as an On Board Diagnostic tool for car monitoring. The brain of the device is again the ATmega8 AVR microcontroller from Atmel, with 8KB of flash memory (this is more than enough for all kinds of features, since the basic source code is only 3KB).
The device supports serial RS232 for connection with the automobile, different baud rates (varying from 9600 to 115200 Baud), 4 different bus monitor functions and can handle header messages of 1 and 3 Bytes long. The circuit was designed for a single layer PCB and, starting with firmware 1.04, the device has a crystal 7.3728MHz. The controller is programmed using the ISP connector.
The interface has been tested with various ODB software, including Scantool.net, wOBD, Scanmaster and many more. A .pdf file containing the schematic, parts list, bill of material and other information regarding this project is available in the link below, as well as the source code, released under GPL.
AVR J1850 VPW Interface: [Link]
There are dozens of projects like this one on the web, but it’s nice to be able to chose the one you like most. Nothing special with this AVR ISP programmer, maybe just the idea that the author build it because hi’s hold programmer was working trough serial connection and as most modern devices work on USB he decided to make his programmer work on USB.
So, the solution was to replace the two transistors, that were used to adapt the RS-232 voltage levels to TTL voltage levels, with a USB to RS-232 chip such as FT-232BM.
USB ISP Programmer For AVR: [Link]
The circuit contains 2x TRW-24G modules, 1x AT90S2313 microcontroller and 1x MAX202 TTL to RS232 voltage level converter. When you power-on this circuit, the AVR it will configure the IC1 as receiver and IC3 as transmitter. I’m not gonna give you any more technical specifications because they are well documented on the authors page. I say you give it a try when you need to setup a wifi connections between AVR’s.
Experimenting Wireless Comunications With AVR ATtiny2313: [Link]
The RGBLED and mRGBLED controllers allow you to control the color of RGBLEDs. This might sound trivial, but it actually takes a lot of resources to let you be able to set an RGBLED to any color you’d like. In addition to just lighting an LED up with a given color, these boards also let you install a color or setup transition/animations effects. They are easily controller via an RS232 connection (serial port) or an SPI connection (logic level).
The boards can be built reasonably inexpensively and there are PC boards available for either model. All source code for the onboard PIC processor as well as the software for configuring and using the controllers is available. The protocol is a simple protocol well documented.
I’m currently studying timers and pwm control on AVR’s so i can build my own projects related to controlling RGB LED’s. I hope I’ll get something up soon.
RGB LED PWM Control Project: [Link] – [via]
I say another, because we all know the DIY MP3 Player and the AVR Butterfly MP3 Player. This mp3 player can support up to 4 GB of storage (MMC or SD cards) runs from a single AAA battery and has full user control (volume, track, pause, skip, directory) with a 5-way micro joystick.
Also the LCD has contrast control, you can record voice and the firm-wire is totally upgradeable trough RS232. In fact this DIY MP3 player is the coolest I’ve seen so far and it’s full of tricks.
EchoMp3 Another DIY MP3 Player: [Link]