Do any of you have projects you designed and built that are still running after many years. If so I would like to hear about them. I have 2 digital thermometers I made. The first one I built in 1982 using one of those 7106? IC's. The second one is a re-design I built in 1997 using an Intel 8048 microcontroller. Both have been running 24/7 all these years.

 

Hasn't been running 24/7 but still works. In 1972 I designed and built a Color Organ, used triacs controlled by home made optocouplers made with incandescent bulbs and photo cells. Audio amp with 3 channel filters from caps and chokes drive the light bulbs. Hook it to the Christmas tree lights every year. Only failure has been the light bulbs.

 

I didn't design it but I built a Dynakit Stereo 120 (60w per channel), one of the first solid-state basic stereo audio amps, waaay back in the 60's and it's still going strong. Only had to replace one electrolytic coupling capacitor in all that time.
I use it now to power the speakers on my computer for music and it still sounds really good.

 

http://forum.allaboutcircuits.com/blog/lm723-as-a-thermostat.532/
http://forum.allaboutcircuits.com/blog/night-detector.658/

 

The first balanced circuit I designed and built was a microphone preamp and cough gate for a TV station master control room announce booth. 1975, still in use today. The first digital project was in 1967, a game show controller my high school used to practice for the local TV quiz show. First person to press a button lighted a light and locked out all other buttons. All relays, but hey - gates is gates.

ak

 

Thanks for your replies, I find them all interesting. I dug up another old project today, I built an outdoor lighting controller for a friend who owned a commercial building. It was installed 05/1994 runs 24/7 and is still working today.