Proto board programming question

PFloyd36069

Hi guys,

Well The other day i was running my steppers and i left·one draw too much current and blew the transistor array, which then blew pin 3 of my demo board. So i got on parallax.com and saw that the proto board was·on sale and i bought one. But i didnt get the prop plug. Is there any easy way to program this·board without it? Does it have to use USB or can it use the regular serial port? Does it have to have the reset pin hooked up or can you manually reset it?

Thanks,

Bryan

Post Edited (PFloyd36069) : 2/7/2009 4:30:14 PM GMT

rjo_

"regular" means 5Volts?

no... don't .

the Protoboard has two versions, one that you can plug directly into a USB and one that requires a propPlug...
If you aren't sure which one you have, it is safe to just plug and play and see what happens.

Sorry about your demo board... let it rest and see if it is still dead.

If you had used relays rather than transistors, this wouldn't have happened... I did the same thing... once.

(you can trigger a 5volt reed relay (from Radioshack) directly from a prop pin... so the package says "5 Volts" but it really means 3 volts [noparse]:)[/noparse]... the experts worry about back current, but so long as you aren't using high amp steppers, it doesn't seem to be a problem.

PFloyd36069

thanks for the quick reply rjo,

When you said "no...Dont" you meant dont use the serial port right? I have the board that just has the place to hook up the prop plug... no usb. My motors draw 2 amps and i was running them at 24 volts. Are relays fast enough to drive a stepper at high speed?

kwinn

PFloyd, buy a prop plug. once you have one you can use it on any protoboard for future projects. Cheaper in the long run.

As for running steppers or any equipment with high voltages and currents always use opto isolators to protect the prop. A 4n33 for example can be connected to a prop pin with a 180-220 ohm resistor, and can provide up to 150mA at up to 30V on the output. It can be switched at up to 10KHz. If you need to switch faster there are other devices available.

I have used this and other optoisolators in all my designs for many years and I have never had a failure in the power drive circuitry damage the control circuitry. Worst case you end up replacing the optoisolator and everything beyond that.

Cluso99

If you haven't blown the USB section of the old protoboard (which obviously has the usb), just cut the tracks and join the wires to the new protoboard.

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Michael O'Brien

Hi,
You can also use the prop clip (used for the spinstamp) if you have one.
/michael