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shamiehf
11-21-2006, 04:56 AM
I am a mechanical engineer and I'm not quite sure where to start. I'm looking to control about 20 two-lead push-pull solenoids through either a serial or parallel port. These are 6-12V solenoids and the type of control I need will be a sequence of commands (i.e. #1 on, #2 on, #2 off, #1 off, #3 on, etc...). I am familiar with programming and don't mind the language that I am confined to. What I am looking for is help on the selection of hardware to act as the interface between my device and computer. I've heard from people that Parallax offeres everything I need from start to finish, but I don't know where to start. Any help would be appreciated. Thanks in advance.

stamptrol
11-21-2006, 10:39 AM
Shamief,
In principle, what you want to do is quite simple.

We need a bit more info as to the current drawn by your solenoids, how fast the sequence has to operate and whether any other control functions have to be accomodated.

Briefly, you'll be able to drive the solenoids by choosing a transistor array or individual transistors to handle the current of the coils. To get the number of outputs required, you'll use a shift register chip or similar technique to "multiply" the number of stamp outputs available.

More details or sketches would relay help!

Cheers

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Tom Sisk

http://www.siskconsult.com

jhoyoza
11-21-2006, 01:41 PM
Trust me…I’m no expert, but perhaps this might be helpful?

EBAY: 4-CH TTL Driv Relay PCB for Xmas decor, Basic Stamp PIC

This is a relay board that is very simple to use with the basic stamp.

http://cgi.ebay.com/4-CH-TTL-Driv-Relay-PCB-for-Xmas-decor-Basic-Stamp-PIC_W0QQitemZ180051069724QQihZ008QQcategoryZ78205Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem

If you were to buy a Basic-Stamp starter kit:

http://www.parallax.com/html_pages/products/kits/starter_kits.asp

and a few of these relay boards, you could be turning things off and on in no time. As the ad says perfect for, “driving heavy inductive loads such as AC motors, magnetic lock etc.” Relays contact spec - 250V, 10Amp (Not bad for around $10) TTL logic control input is perfect for the basic stamp.

Of course stamptrol (above) is right, it very much depends on what your switching and how fast? (Cover your ears warranty dept. http://forums.parallax.com/images/smilies/tongue.gif) I did switch heavy loads at better than 2 Hz, for a time, and the relays seemed to hold up just fine. For how long is another story?

Only issue I see is that the 24 pin Basic stamp has only 16 outputs. But, I think there are ways around that too, or you can buy the BS2p40-IC and it’s starter kit as it has 32 outputs.

-Cheers

Post Edited (jhoyoza) : 11/21/2006 6:50:25 AM GMT