I think I killed my USB Experiment Interface Board

Kits PC Related Projects
1

I built the K8055N kit, ran the demo and everything appeared to connect and work as it should.

Then I tried to use the board to make a USB cable that can be turned on/off programmatically. (I split the red power cable and connected one side to digital Output terminal 8 and the other to GND)

After this I ran the demo app, but it would not detect the board. IC4 became extremely hot. Now the board powers up -Power LED is steady and LD8 blinks briefly as normal but I still can’t connect.

Should this have worked, and how can I fix it now?!

Cheers,
Al

2

Please study how the digital outputs work before doing dangerous things with them! Ofcourse IC4 gets hot! The outputs switch to ground so when you activate output 8, you are connecting the + of your USB to ground = short circuit!

3

Incredibly, after cooling down for a few hours it now seems to be working again! Guess it’ll take an even bigger idiot than me to break this :wink:

I bought it to mimmic button presses on a digital camera and connect/disconnect USB. Is that possible with this board?

4

If all buttons of the camera are connected to the ground of the camera, it is possible. Can’t predict that for 100% sure because it depends on the signals and internal connections of the camera.

5

Think this could work for switching the power on the USB cable? Hope this makes sense :slight_smile:

6

NO it can NOT!
Please read my earlier message! The digital outputs connect to GROUND so if you activate Output 8, you connect the + of the USB to ground = short circuit!

7

[quote=“laserguy”]NO it can NOT!
Please read my earlier message! The digital outputs connect to GROUND so if you activate Output 8, you connect the + of the USB to ground = short circuit![/quote]

Thanks for the warning anyway, I should probably get a relay board instead, much more forgiving.

8

That will be safer indeed ;).

9

I’m a little puzzled about what you actually try to accomplish here.

Using the very K8055(N) to turn off it’s own power supply sounds like cutting off the branch you’re sitting on.

Using a PNP transistor and a few other passive parts, you can certainly build a USB cable and control it’s power via a K8055(N) digital output. But that would only be good to control another USB device. Not the controlling K8055(N) itself.

Jan

10

No, I don’t think he is going to do that. He wants to make an USB cable for a photo camera and I suppose (first message) it is the power of THAT USB cable (to the camera) he wants to switch on or off.

11

Oh, I missed the “To Camera” part in that picture. Thanks.

Well, USB can only provide 500 mA. So a variety pack transistor and a few other parts will do the trick then.

Jan