NK204-V / relay control of stoplight through GPO's

Kevin · Post by **Kevin** » Wed May 01, 2002 8:08 pm

Hey, I've been lurking in the forum for quite some time and drooling over the LCD goodness available at MO, and I finally broke down and got one. It's the NK204-V that bit-tech did the piece on. While I am waiting for the lead time to finish, I'm thinking about possible things to do with it. One thing that I have come up with that I thought would be cool is to control my traffic light through a GPO. My traffic light is an antique light that actually used to be hung up at an intersection, and now it's propped up against my wall. It's been rewired, and when I plug it in, all three lights light up at the same time. This is okay, but what I thought would be cool is to control the three lights through software, flashing them when email came, etc. I understand this can be done with the GPOs on the lcd and relays. However, I know very little about electronics (I can sorta read schematics) and I've never used a relay before. How would I go about using one / three (one for each light) to control this light? I have opened up the light and it's wired up very shoddily (just a little electrical tape holding everything together) but very simply. It would be easy to stick three relays inside of the light; there's plenty of room. What do you think?
Kevin

dVs · Post by **dVs** » Wed May 01, 2002 8:40 pm

I think thats a mighty fine idea, but unfortunatly i can offer no advice on how to go about wireing it up as i've never really done anything like that either.

Post by **Henry** » Thu May 02, 2002 9:26 am

Well, if you do a search there is a number of threads about relays and so on... I think it will be possible... why not... you can use each GPO for a light.

Kevin · Post by **Kevin** » Thu May 02, 2002 10:49 am

I did find a thread about relays that had a couple of useful schematics, but they were for controlling fans. What sort of relay would I use to turn on/off full A/C 120V current from the wall? What components would need to be replaced? The thread I found was at http://www.lcdforums.com/forums/viewtop ... forum=1&12

Post by **linear** » Thu May 02, 2002 12:09 pm

Optocoupler triacs are the answer, as shown fairly well at the venerable Discolitez site.

But USE A FUSE in the mains side of it for safety.

<font size=-1>[ This Message was edited by: linear on 2002-05-02 12:10 ]</font>

Kevin · Post by **Kevin** » Thu May 02, 2002 3:38 pm

Optocoupler triacs? I must confess I've never heard of these before. What would the advantages be over traditional relays? The relay seems to be a bit simpler (http://www.discolitez.com/circuits-ssr.html)

Thanks,
Kevin

Kevin · Post by **Kevin** » Thu May 02, 2002 9:46 pm

What about solid-state/semiconductor relays? I found a nice page on them at http://www.hut.fi/Misc/Electronics/circ ... elays.html . Apparently, most of these use the optoisolated TRIACs setup too, but are integrated onto an IC. These seem useful...

Post by **linear** » Fri May 03, 2002 10:54 am

For sure, there's more than one way to do it.

I think the advantage of optocoupler triacs is cheapness compared to solid-state relays. I'll also confess to hating relays, so I may not be entirely objective about it.

Nice link you found, BTW. I think this is the approach I'd take:
http://www.hut.fi/Misc/Electronics/circ ... normalopto

<font size=-1>[ This Message was edited by: linear on 2002-05-03 10:57 ]</font>

Kevin · Post by **Kevin** » Tue May 07, 2002 12:21 pm

just got my lcd in the mail yesterday. It's up and running with no problems. Wheeeeeeee!

Adam · Post by **Adam** » Tue May 07, 2002 1:22 pm

Show us pic's when your done.