6 replies to this topic

[Domenique]

Hi all,

 

I'm at the point of loosing my mind. I'm at the wiring stage of my cabinet build and for some reason I can't get my Pinscape outputs to switch a simple led through a LED amplifier. As I first started I broke my KL25z board, I allready replaced it and carefully tried again with measuring voltages on every single step. Still, the same result:

 

Who can tell me what I missed?

The goal is to hookup the pinscape outputs to my RGBW Led amplifier to control my LEDs. See the diagram below.

I followed the exact instructions in the Pinscape buildguide [1] and all I have these test results:

• The LAMP in the test diagram turns on if I connect the Amplifiers (1) input to the common ground
• The KL25z output port is set to active low and reads 3.3V when off, and 0V when on in the output tester
• The tests mentioned in the Pinscape build guide are all succesfull (both the "is my amp suitable for Pinscape" and the "Pinscape output voltmeter test give me the expected results).
• All button inputs work as expected (nothing to do with this problem statement, but just to let you know :-).

 

The problem: When I connect (any of) the KL25z output to the amplifiers (1) input, the LAMP doesn't turn on when I switch the corresponding output in the Pinscape output tester.

 

I also tested with a ULN2803 chip between the KL25z output and amplifier without active low setting (the voltmeter tests are again correct: 0V when off, 3,3V when on): same result, no switching.

 

I'm starting to get desperate and want to prevent careless debugging with the risk of toasting my Pinscape board.

 

[mjr]

I sure don't see anything wrong in your wiring diagram.  Since you're seeing the correct voltage pattern on the GPIO pin, I think we can rule out software configuration problems or KL25Z problems, and assume that the problem is in the LED amp or the wiring to the LED amp.

 

The only thing I can think of is that maybe you need to provide power (probably +12V) on the "V" input to the LED amp.  I know there are at least a couple of different designs out there, and some of the designs might be wired so that they'll only work with power on the input side.  BEFORE YOU DO THAT, though, disconnect the KL25Z from the LED amp, and repeat the voltage test on input pin that connects to the KL25Z, to make sure that it doesn't read above 3.3V.  I think that some of the designs have an optocoupler in there that the controller is supposed to short to ground to turn on the channel, and that might be connected to +12V internally.  That would be dangerous for the KL25Z.

 

For the ULN2803, if you could post a diagram of how you're wiring that, I could take a look and see if I can spot any problems there.

 

(I'm a little confused by the 1-2-3-4 numbering in your diagram - was that supposed to be just 1-2-3?  These things usually have three channels, for R-G-B.)

[Domenique]

Thanks for your reply. The RGB amplifier is a RGB+W amplifier, hence the 4th input pin.

 

Tried the same with a "in line" RGB amplifier btw: same results.

 

Here is a diagram including the ULN2803. Of course, as per documentation, I did NOT enable "active low" on the output port when using the ULN2803:

 

[mjr]

It looks like you're using some kind of breakout board for the ULN2803, so I'll have to assume that you're following their instructions for wiring it, but otherwise it looks right.

 

Have you tried a basic test of the amp wiring without the KL25Z involved?  For the RGBA amp setup (leaving out the ULN2803 for the moment), the light should turn on when the input is grounded.  So you should be able to set things up exactly as per your original diagram, but remove the KL25Z, and test the light by directly connecting the RGBA input to ground.  It should turn on when the RGBA input is connected to ground, and off when it's connected to 3.3V.

For the ULN2803 setup, the test is reversed: the light should turn on when the ULN2803 input is connected to 3.3V, and off when the input is connected to ground.

[Domenique]

The first test I did was connecting the RGBW amp input to ground without; the light turns on.

 

For the ULN2803: I just draw a simple diagram, no breakout box: 8 input, 8 output, a ground and a common. thats a basic ULN2803? Right?

[mjr]

Well, that's sure bizarre.  It seems like you've tested every piece individually and found it all working correctly, so the only remaining possibility would seem to be a bad wire connection somewhere.  The only thing I can suggest is to go back over every test and every connection, one at a time, with an extremely critical eye.  I've definitely had my share of weird situations like this where it turned out that I was just hooking up a wire to the wrong pin all along, and just kept missing it until I went over every detail again from scratch.

[Domenique]

Just wanted to report back; I've re-done all my wiring (or mainly, all wire connections) and got the setup working using the ULN2803. 

 

Thanks for your help mjr!