any way to get more GPO's ?

Archmage · Post by **Archmage** » Tue Jul 30, 2002 3:14 pm

Hey, I was wondering if there was a way to use more GPO's than the 8 that come with LK204-25PC for instance ? Perhaps an add-in board or something? I need maybe 12 or 16 to control: Fans, Lights, pumps, motors, etc.

thanks for any help.

Archmage · Post by **Archmage** » Wed Jul 31, 2002 8:10 am

Perhaps the Parallax Basic Stamp controller boards ? I just did some research and it seems as if they MIGHT work... The basic stamp 2sx has 16 i/o pins... http://www.parallaxinc.com

I just need to find out the following:

1. Will that allow me to control more devices
2. Will I be able to interface it with the LCD
3. Will it run on a USB converter with the LCD USB-converted as well
4. Are there better options...

Of course if I find the answers, I'll post here, but my guess is that I'll have to send out a few e-mails...

EDIT: It seems as if the "PicBasic" microcontrollers would be a better option...though they are the same type of thing.

jleach · Post by **jleach** » Wed Jul 31, 2002 9:17 am

I think using a basic stamp or other microcontroller is the wrong way to go. I know people have used them to control the display but that's not really what you want to do.

If you just want more GPO's then there are a couple ways to go. First off.. 8 GPO's is a lot. Using a relay or transformer there is no reason you can't power more than one fan or light off of one GPO. Of course they will turn on and off together but that's not a problem for something like case fans.

I'm 'working' on a circuit that will take the outputs of a pair of GPO's and provide four levels of power to my aux intake and exaust fans. I'm basically using the outputs of two GPO's as 'bits' to specify the binary numbers 0, 1, 2, & 3 (00, 01, 10, 11). It's _possible_ to build a circuit that would use all 8 outputs to generate up to 256 different events (2^8 being 256 and all).

Unfortunatley I don't have a lot of free time and I've not finished (okay, maybe i've barely started) the design of my circuit so I'm going to be no help on a more complex design. I just wanted to let you know it's possible.

Of course, if I ever get finished with my circuit i'll be sure to post it. Too many things on my plate right now, tho.

[ This Message was edited by: jleach on 2002-07-31 09:18 ]

Archmage · Post by **Archmage** » Wed Jul 31, 2002 9:29 pm

Sounds good, the power requirements on the LCD seem to be met, but I'm not positive on that. In any case, here is what all I want to do:

1. Switch on/off 4 fans and be able to RPM and/or voltage monitor them individually (I have a home-built rheobus (Though I am making another one for this)).
2. act as a relay switch for an Eheim 1250 pump and another, different pump.
3. Be able to turn on/off at least 2 motors at the same time (RC car motors)
4. turn on/off backlighting with the case's UV lighting switching concurrently with it (and an option for just normal lighting control). Possibly replace the backlighting with EL cable to achieve this effect more easily ?
5. Monitor and display 4 separate temperature readings.
6. All the normal functions that the LCD already had.

blah...I'm thinking I'll look into what you are talking about...

Thanks for the advice...

Edit: QUOTe " Using a relay or transformer there is no reason you can't power more than one fan or light off of one GPO." --- does this mean to affix extra power or what ? If it does, then I think it will all work...

Any info on this is appreciated

_________________
"Beware of Guildolio of the guilds of the guilds in terra!"

[ This Message was edited by: Archmage on 2002-07-31 21:38 ]

[ This Message was edited by: Archmage on 2002-07-31 21:39 ]

jleach · Post by **jleach** » Thu Aug 01, 2002 11:30 am

Yeah. The GPO's on the LK204-25PC can supply 'only' around 750ma and 12v. If what you want to power off of 'em needs more juice you'll need to use a relay or transformer. The relay or transformer would be activated by the GPO and would switch power you supplied via your power supply or whatever.

Post by **Henry** » Thu Aug 01, 2002 11:46 am

I have pushed the LK204-25-PC to over 1.1Amps per GPO...

jleach · Post by **jleach** » Thu Aug 01, 2002 1:31 pm

Well Henry, you've got a bin of displays and spare parts to pull out of if you blow yours up.

I knew that the GPO's can supply more than the 750ma that they are rated for but I was being conservative and quoting the rating instead of what it can actually do.

Here is a link to 'overclocking' the display. http://www.matrixorbital.com/projects/l ... rclock.htm

Enjoy,
James

Post by **Henry** » Thu Aug 01, 2002 1:34 pm

LOL... you like my heatsinks... hehehehe...

and I have a pile of dead stuff... you should have seen when we were testing the high power GPOs here, all you hear was POP, and then smoke... hehehehe.... nothing like destructive testing.

_________________
Henry J.
Head of Technical Support
Matrix Orbital

[ This Message was edited by: Henry on 2002-08-01 13:35 ]

Archmage · Post by **Archmage** » Thu Aug 01, 2002 2:55 pm

Oh i understand it now! Great...I believe that I will be able to do this without a microcontroller now...

As for adding the heatsinks: OF COURSE I WILl ! hehe...need all the power i can get.

Thanks for the help