Hi,
I just did the first test to connect the K8055N with my mini laptop (an Acer Aspire One).
I did not successfully run the first test. The power on led on the K8055N did light ok, but I did not get a blink from digital output led #8.
My laptop showed a popup saying: “power surge on unknown device, please disconnect or this USB port will no longer be available”.
Tomorrow I will get out my multimeter to find out whether the are any shortages in the USB connection.
So far I’m a bit puzzled. Is the K8055N drawing too much power from my mini-laptop?
Can I use a separate +5V power supply to power the K8055N board?
If I do should the USB +5v line still be connected. I suppose so, but will I be feeding +5 back into the laptop?
Regards,
Reinhold
Unfortunately this site does not allow uploads. Please upload “clear, sharp, high resolution” pictures of both sides (soldering and parts) of the PCB to a free picture site and post links here.
The K8055N, if properly assembled, does not draw nearly what any USB port must supply to be even half spec compliant. And when it comes to “little” notebooks, like your Acer, they usually do better than you’d expect. I have a bunch of netbooks (ASUS 1000s and 1250s). The K8055 and K8055N works fine on any of them.
Do NOT mess around with pumping more power into the board. There is clearly something wrong with the assembly. You will only cause more damage to components on the board, your notebook, the power supply or all three.
Did you notice if any of the components on the board got hot, when you connected it? Double check that all ICs are inserted the right way. Compare the notch on the IC to the silk screen print on the PCB.
Thanks for the feedback. I did not have time to take pictures yet.
I’ve been testing with the multimeter to figure out what’s going on.
On the USB resistance between +5v and ground are down to approximately 22 ohm.
That sounds low to me.
First I suspected the USB connection since I had extended this through a cable to place the connector on the outside of the cabinet in which the board will sit.
I removed those connections, measured resistance, still 22 ohm.
I took out all IC’s. Now resistance was high, 15 K ohm.
I plugged the PIC IC back in, resistance between +5V and ground was down again at 60 ohm.
Hmmmm.
Later today I can take a few pictures, but I checked quite thoroughly and did not spot anything strange.
All IC’s have their indents pointed is the same direction, as the white drawings on the board.
Any clues or ideas what to test next?
I got a lot further, ISSUE RESOLVED!!
I placed all IC’s back on the board and connected to the laptop. The board worked ok!
Hmmm I thought, what is different?
Probably the USB connection was shorting the +5V to ground, at least enough for the laptop to complain about it.
I suspected the USB connector to be a bit dodgy, or the USB cable that I am using.
To my relief even the relais worked as planned when I connected them to the system.
Anyway, after some testing, the board stopped working and the connection was lost.
I found out that it was the USB connector, when I put it is straight it is ok, but when I wiggle it a bit the connection is lost.
I could repeat that issue enough times to know for sure this is the problem.
edit --> I found the culprit, it was a bit of sloppy soldering and issues with the wiring. The latter probably had a broke line somewhere which caused the connection to fail after some wiggling of the connector. The connector turned out to be fine, I just had to redo the wiring.
Hope this stream will be useful to others as well.
Regards,
Reinhold
Reinhold,
it will be useful to those, who seek knowledge. There isn’t much you or I can do about the rest of them.
We used to say that 99% of all “connectivity” problems stem from bad connectors, bad cables, bad jumpers, you name it. You “wiggle” a cable and something changes. The WiFi age and the AyePhone may have changed that percentage a little, but certainly not by much.
Now that you solved this, what are you going to do with the board?
Don’t go away. Stay and share your “experiments” with us.
Jan
The purpose of my experiment is to be able to control multiple Kodak Carousel slide projectors.
The eight digital outputs of the K8055N will enable eight groups of projectors to be driven simultaneously. I’m using a bunch of old but still reliable telecom relais Siemens V23154-D0721-B110 (a data sheet can be found on the internet, which is very useful) and has four independently switched groups. They are designed to operate at 24V, but experiments showed they work just fine under 12V as well.
The interfacing basics for the Kodak Carousels are simple:
Each is normally controlled by a remote that is connected through a DIN 45322 connector. A short connection between pin 2 and pin 3 will signal the projector to move one slide forward.
I have eight relais driven by the K8055N, as explained on page 13 in the booklet that came with the K8055N. I only added a protecting diode to each relais (cathode connected to the +12V) just to be safe. I know the ULN2803 has the same safetymeasure built in, but it’s a cheap extra insurance not to blow out the board by the kick-back of a relais being released.
For power I have used the switched power supply of an old Compaq computer. This needed two tricks to make it work independently: a “power on” signal lead needs to be connected and a load of about 20W is needed on the +12V output. I’ve use a halogen 12V 20W lamp for this purpose. It illuminates the cabinet for this setup from the inside with the bonus of being able to find the projector and USB connections in the dark.
In the case of my old Compaq the signal lead was coloured white and had to be connected to +5v (red) before the power is switched on, this took a while to figure out. Be careful as older Compaq’s have non standard cabling, and I won’t vouch for the color codes. It will be much easier and safer to use and old ATX power supply instead. For these there are “how to” instructions to find on the internet. Note that for ATX power supplies the signal lead must be connected to ground.
8 channels times four switched projectors means my setup allows 32 projectors to be driven from a computer. The USB connection of the K8055N makes it an attractive solution as I can use almost any laptop to control it for a show “on the road”. I will be using an Acer Aspire One.
In reality I don’t think I’ll ever use more than eight projectors simultaneously but it’s great to have some room for extension to what could be a monster setup.
That sounds like a big slide show. Nice project.