> Very nice write-up! It is nice to have someone take the time to > present such a detailed description. Thanks > If I may add a few thoughts. The "proximity switches" come in 3 > types, the most common is "form A" which is closed circiut in the > presence of a magnet (and most common because they are used in alarm > systems). Then there is "form B" that is open ciruit in the presence > of a magnet (good for door switchs since they draw no current when the > door is closed). That's what I thought and was what I was trying to get, but for some reason it operated opposite of what I expected. I might have just gotten my order wrong. > "Form C" has both open an closed circuits (3-wire SPDT). Ah, I didn't know about those. Cool. > I built a similar circuit for my car and wanted to share a few > things I learned. With normal bulbs, the D's door lights pull about 1 > AMP each side. It is abut 1/10 that or 100 mA with LEDs. The typical > magnetic switchs is rated for 500 mA for form A and 250 mA for form B. > So, it is probably good that you used the transistor. I also have LEDs in my doors. I admit it didn't occur to me that I'd overpower the switches if I was still using normal bulbs. Looks like I just got lucky. :) > I used the form B switch with a relay so I could do the function of > both of the > driver's side switches with one magnetic switch. The down-side of the > relay is that you have to wire it to a power source under the dash > (only used when the door is open). It would have probably been simpler > to use a transistor like you! I actually wanted to just use a single magnetic switch, but I couldn't quite figure out a good way to do it with one switch. And I didn't think of finding an SPDT one. Or a DPDT one, although I'm guessing those are pretty hard to find. I avoided a relay only because I was concerned about having it energized while the doors were closed, thus unnecessarily draining the battery by some small amount, and I figured the transistor would draw much less power. I was probably a little too paranoid there. Even so, the transistor setup also required an extra power source to function. > I too, really like the results. I never have to worry about the > switch alignment again. There is no contact between the magnet and the > switch. > Again, I appreciate the write-up. No problem. Thanks for the extra info! -- Joe To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/