Manipulate plugs to power a LED

[tobigirst]

Hello!

I want to power a optoelectronic coupler with a connector on my Computer. So when I run a AU3-script, the optoelectronic coupler will turn on for 100 milliseconds.

on my computer I have the following ports: Loudspeaker, Ethernet, USB2 (no serial or printer port).

I already tried to use the NUM, CAPS and SCROLL- Leds with the SEND-Command, but on my HP-Win7-Computer they do not always work and are not relyable enough.

If you wonder why i want to do this: the optoelectronic coupler triggers a swich which is connected to some electronic device.

I already asked a similar question on http://autoit.de/index.php?page=Thread&threadID=31634, but could not get an answer.

[BrewManNH]

You might be able to do it through the USB port, or with an Arduino board, but not sure how you'd go about doing it.

[jchd]

From what you say, the cheapest way to power an opto-coupler will be using an USB to serial adapter. You can find many of them on every buying platform, but make sure you get one with a working driver!

Then double check that you won't overdrive the LED and place a diode in series (stock 1N4148 or equivalent will do) as many opto-LEDs don't like reverse-voltage very much.

Which opto-coupler do you plan to use? Put otherwise: which load do you want to pilot and under which power source?

(My avatar should give you a hint as to why I'm asking.)

[tobigirst]

Thanks for your answers.

I already got a Arduino One from a friend of mine, but I do not know how to program it.

I currently use a CNX82A. directly connected to the SCROLL-LED of a USBKeyboard.

But of course, I would be able to spend small amounts of money for other parts.

Could you explain how to write the code for the USB2Serial-Adapter? Is it possible to do it with AutoIt(+DLL)?

I'm sorry for being such a noob, it is my first hardware-related AutoIt-script.

tobias

Oh, this came just in my mind: would it be possible to use the loudspeaker/headphone jack to transmit a 10 Hz rectangular wave (it must be possible to set the amount of oscillations, so I can control how often the swich will be triggered.)

Edited May 11, 2012 by tobigirst

[jchd]

Using the heaphone output is going to be messy and not reliable. Using an Arduino for that is gross overkill.

Try hunting for a simple USB-Serial adapter. Several come without any need for a driver (depending on your OS version and date).

Once you have it plugged and installed, use Martin's UDF for serial ports: see There are plenty of examples floating around. Pulsing DTR or RTS for precise time at required instant is then very easy.

Use one of the basic output control lines (DTR or RTS) with a blocking diode to keep the emitter part of your CNX82A alive (this model has a reverse breakdown voltage of only 5V, so if your serial adapter has this control line swing in +- 12 or possibly +- 15 V range, you're almost sure to fry the emitter). Note that some adapters have a non-standard output range 0..+5V only, but it doesn't hurt you. You can optionally insert a series 1/4W few hundred Ohm (try 220 Ω) to keep the current to the emitter in the allowable range (10 mA is enough to drive it, maximum is 100 mA but I doubt any USB-->serial adapter has such a fan out that your petty opto-coupler risks anything).

Ask if something is clear as mud.

[tobigirst]

clear as mud. lol.

Thank you very much for your quick and competent answer. Unfortunately, I don't have much time (school-.-) at the moment to try it out now. But you helped me a lot! I am going to try it as quick as possible! I think, this is [solved] now. (Maybe you guys will hear from me in half a year...)

tobias