Hi all,
I have a simple circuit with a led and a rezistor. What i managed was to put the circuit on ground and put labjack pin to 5v and the led is ligh
What i want is actually to put circuit on 5v and labjack pin to ground to light the led.
Any ideea of how can achieve that?
I am not exactly following. See if the following LED app note helps:
https://labjack.com/support/app-notes/driving-leds
What you suggested me is exactly how i do it now, but i don t want like this.
I draw a little schematic to be more clear. In the draw we have a led, a +5v (same as labjack is powered - from usb), a GND (from labjack).
In my draw if i put pin 1 to GND led will light. This is what i want to achieve. To have nothing on pin 1 and led is off or to have GND on pin1 and led will be on.
I actually ground it that pin
I do not see an attachment or link to a drawing.
Are you saying you want to connect:
VS to LED-Anode
LED-Cathode to Resistor+
Resistor- to FIO0
That is what is described in #2 in the Driving LEDs app note:
https://labjack.com/support/app-notes/driving-leds
The digital I/O on the U3 have 3 states:
Input (high impedance input, weak 100k pull-up to 3.3V)
Output-High (connected to 3.3V)
Output-Low (connected to GND)
So if you want to change FIO0 between high-impedance and ground, which is also called open-collector operation, you change FIO0 between input and output-low.
The following might also be useful:
http://forums.labjack.com/index.php?showtopic=596
http://forums.labjack.com/index.php?showtopic=6334
Thank you very much