Current generation for USB 6218

[Misere]

I'm a biologist studying bats in a behavioural set up using one USB-6218 card so this electronic stuff is a steep learning curve. Sorry if this is a no brainier but! I already have used: 7 of the 8  digital channels for port 1 to control seven 5 volt relays 6 of the 8 digital channels for port 2 to detect six 5 volt pulses from six infrared sensors.These are all working fine but I still need to supply five LED’s with power to signal the animas to move to five different locations within the set up. Only one LED can be on at a time so how do I generate the voltage with my remaining channels? CheersJosh

[xdaf]

So, if I understand correctly, you have 3 digital lines left, and you must drive 5 leds.

You should generate a 3-bit number, and then use an external binary to decimal converter (such as  74xx42). Fan-out current should be enogh to turn-on the led.

[Misere]

Right, did not understand even half of that!

Right so I need to get new hardware then? Is is possible to generate voltage from any of the other lines? 

[xdaf · Accepted solution]

Sorry for not being clear!

Yes you need new hardware, but only a really simple integrated circuit, such as SN74LS42 (just google-search for "SN74LS42 datasheet"). You'll probably find it on specialized shops for less than 1$.

Connect supply to +5V & GND pins, and your free DAQ digital outputs to inputs A0, A1, A2 of the decoder. According to the status of such inputs (8 possible combinations), one (and only one) of the Q0 ... Q7 outputs will be activated (for example, if A0,A1,A2 = 0,1,1 output Q3 will be activated).

Hope this helps!

[Misere]

Sweet thanks! Man I love you internet ninjas!