Homework Board Relay Control? Or other Method?

divzr0

Hey guys

I have had the Homework board for some time and I have been thinking about using it for a project.

I would like to utilize the stamp to switch a relay.· I'm thinking of having the relay control a model rocket ignitor, or (4th of july is coming) other pyrotechnics.· In my testing the board cannot source enough current to switch a 5V low signal relay which controls a 12VDC battery supply.· I looked at a relay supplied by parallax for industrial control but it was 10 dollars a pop.· I was thinking of making a 12 channel setup, at that price it would be well out of range.

I have two questions...

1.· Is there an alternative way to switch this 12V supply on?

2.· If I had to use a relay in another project like for turning on 110AC, how can I provide the appropriate current?

Thanks!!!

·

Chris Savage

Hello,

·· Attached is an example of controlling a relay using a Stamp I/O pin.· Now, if you have the correct power transistor then you could eliminate the relay altogether.· As for your second question you would need a solid state relay.· Please see the following links.

http://www.parallax.com/detail.asp?product_id=31204

http://www.parallax.com/detail.asp?product_id=400-00010

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Chris Savage
Parallax Tech Support
csavage@parallax.com

divzr0

Thanks Chris. Any suggestion on what kind of power transistor, or maybe a quick and dirty on how to choose the right power transistor? This part is new to me. Thanks.

Chris Savage

It's all in the details.· You would need to know how much current (max) these ignitors use to choose the correct part to drive them.· Also, how many volts they require.

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Chris Savage
Parallax Tech Support
csavage@parallax.com