Nice Light Emitting Diode Projects

Electronics Infoline Web

LED Photo Sensor Circuit

http://ourworld.compuserve.com/homepages/Bill_Bowden/page8.htm#light.gif

http://www.qsl.net/yo5ofh/hobby%20circuits/led_circuits.htm

using AT89C2051/4051

http://chaokhun.kmitl.ac.th/~kswichit/2051/basic/basic.htm

http://ourworld.compuserve.com/homepages/Bill_Bowden/page11.htm#meter.gif

http://www.nutchip.com/progetti/led_flasher_en.htm

http://www.interq.or.jp/japan/se-inoue/e_ckt14.htm

indicates low-battery condition

http://www.edn.com/archives/1997/010297/01di_04.htm

http://airborn.com.au/pcb01/hseti1.html