http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb 2008-12-02T00:30:00-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t9975.html 2008-12-02T00:30:00-08:00 Hi all,I'm totally new to avr but because me and my teacher are working on the same project I should learn it a bit. So question 1 is: Does anyone know some good sites/ (e-)books?A little bit on the project: We would like to build a miniature of a garage that shows how many parkings are free AND that guides you to a free parking by led arrows lighting your path. A problem we have is how to detect the cars in a cheap way. Therefore I would like to use a led as a sensor. Leds give up a small voltage when light drops in on them. I would like to test if it's possible to use a 2colour led with common cathode to make one half light up as lighting in the garage and one halve used as sensor. (if I'm not mistaking I need a ADC converter?)Is there anyone who can help me get started with this? I would like to learn/use assembler since it is the die-hard way of programming Also have an option 2 in mind by letting the led light up for a couple of µs or ms and then turn it of for a couple of µs/ms to measure. But that would truly be an option 2 Many thanks in advance ! http://www.8051projects.net/forum-t9975.html 2008-12-02T00:30:00-08:00 sashijoseph Hi Zatar...There's a nice tutorial right here in this site,which will quickly get you in business.Look here : http://www.8051projects.net/avr-microcontroller-tutorial.htmlAbout your project; you can use an infrared led-infrared sensor pair for detecting cars.Wouldn't need an adc.Using a normal led as a sensor could be tricky because different ambient light conditions could affect the accuracy.But with consistent light conditions and careful placement of the LED you could probably put it to use.And yes you would need an adc to measure the small voltage generated by light falling on the led.You could do sth. similar with an LDR as well.