Docs/pics of the 07May2010 board please

[llamapope]

I picked up one of the kits from the Maker Faire and am trying to get it working but it's a bit different than what you have posted. Is there somewhere someone already has some images of this board all put together or would it be possible for someone to post a picture or some documentation of differences on constructing this version of this board somewhere? (even a picture with the strings/frets wired and all the buttons hooked up would be sufficient for my needs)

I think I got it all figured out but wanted to be sure.

Thanks
--John

[Alan Chatham]

I'm sorry, I got those boards in just before Maker Faire (The date on it is the date I finished the design), and so I didn't take any photos of it, and due to lackluster sales at Maker Faire, I'm kinda taking a hiatus from the project (I finally got around to announcing that on the blog, too). But, none of that excuses crappy documentation! Here's a picture with all the components in place (sorry, they're a little bit truncated by the forum, depending on your resoloution - open them up as separate images if you can):


And here's one with all the wires except for the Wii wires going in:

The wires were a bit too thick in this one, but if your wires are thin enough, snake them through the rows of holes that are next to the Wii, Strings, and Frets ports to give you some strain relief - this way, when something pulls on your board, the wires don't snap off at the solder points!

[llamapope]

That's too bad... this is immensely helpful though and I'm way excited to get it all put together and running (and praying that my soldering isn't too horrible to get it functioning).

Thanks!

[Alan Chatham]

Let me know how it goes! One thing is, I never hear about anyone's projects, so I forget that there are some of these out in the wild...

[llamapope]

I got it mostly working and the parts that didn't I think are due to my utter lack of knowledge of circuits and poor soldering practices.

I think I damaged most (possibly all...) of the diodes by putting them in backwards (before asking for clarification) and had to reinstall them... and like a true nub I desoldered them without using any kind of heat-sync or anything. Anyway, it currently works in the fret mode, which is pretty cool, I just can't get it to recognize any chords at all, but maybe I'm misunderstanding how the different modes work. I'll have to look over that again when I get a chance.

Everyone that I've shown it to so far thinks it's a pretty sweet concept and I'm loving the fact that I'm building up real callouses while playing a game. Can't wait to be able to practice some chords too.

I want to get another kit to rig up a second instrument, and if my first kit is indeed not working properly due to some broken/damaged parts, I was wondering if I could buy another set of diodes with it to see if I can get two of these fully functional? I don't know where to get electronic components locally, and if you have enough spare parts, I wouldn't mind saving a bit on shipping.

[Alan Chatham]

I'm more than happy to send you some diodes - when you order hundreds of them, you get them for like under a penny each. I'm glad it's working - there's a small chance that installing the diodes backwards could have damaged the chip, but it's a pretty small chance. Basically, backwards diodes will allow current to be sourced from one pin of the chip and be sunk into another pin, but if all the strings and frets are working (and strum), then your chip is probably fine.

One thing to check that tends to get in the way of switching modes is checking to see if the strings are all electrically isolated from each other. The quick way to do it - in Fret Mode, try pressing red on each string one by one. If one string shows red and green, then that string isn't isolated. If you have a multimeter, touch the first string with one probe, then touch each other string to test for continuity. Check each string this way - if the strings aren't isolated from each other, it won't pick up the transition chords right. Or check to see if the strings are wired up correctly - String 6 usually corresponds to the biggest string, at least how I have them wired up.

[llamapope]

Ok, so I think I got it figured out. It was a combination of some interference issues and not understating how the different modes worked. There still seems to be a few problems, like getting the 'G' to respond consistently... but I might be fat fingering it when I assign it. I had to insulate the copper tape on the guitar neck, it almost makes it nicer to play on, but should that be necessary? Maybe my issue has something to do with how the frets are connected.

Thanks for all the help!

[Yan]

Hello,

First: thank you Alan for your answers by email and your quick shipping.
So my question is: which free pins can I use to solder 3 wires (to install a potentiometer... Yes I known most of them have only 2 pins but in the wii guitar controller, it's a 3 pins potentiometer)? It's 07may board.
As in my emails and on this page (New Functionality), I'd like to use this as a vibralto (or whammy bar).

Bye,

Yan.

[Alan Chatham]

Board w potentiometer.png[/attachment]My understanding is (and I'm really not much of an engineer, so test this all with a multimeter if possible) a potentiometer usually is implemented as a voltage divider. This means that there is a fixed amount of resistance between the outer two contacts, and the resistance from each of the outer contacts to the middle terminal depends on how the knob on the potentiometer is rotated. It's easier to understand with a diagram:
So we attach one of the outside pins to VCC, the other outside pin to ground, and then as we turn the knob, the voltage on the middle pin will change from 3.3 volts (VCC) to zero volts. Then, we'll use the Analog to Digital Converter features of the microcontroller to read that voltage, and we'll know how much the potentiometer has been turned. So we'll only need actually one pin free. However, that pin will need to be an ADC (Analog to Digital Converter) pin, which limits our pin selection a bit. The pin connected to the "6th string" path on the circuit board has ADC, and the Star Power and Pick ports are also choices (with those, we'll have to pick another pin to implement the star or pick functionalities, though). Since you're using only 4 strings with the bass, we'll go ahead and use the 6th string pin. I'll go ahead and make some changes in the code tonight in order to make all that work, and send you a picture of how we'll be connecting everything, but basically, in the slot that says "Diode" that connects to the 6th string pin, we'll be soldering in a resistor and a wire that will go to the potentiometer, then connecting that resistor to VCC and the other wire of the potentiometer to ground, making a voltage divider.

Attached to this post is a picture of where on the board to solder in the wires going from the potentiometer - let me know if you can't see it or if it's unclear.
[attachment=0]

[Yan]

Hello,

So you've made again a lot of works!
As I said by email, I'll install first on a guitar so I need all the six string pins.

I've checked the resistance of the potentiometer with a multimeter and here is the result
-between the first and the second pin, the resistance varies (I don't know if it's the good word) between 25 and 3000 ohm
-between the second and the third, the resistance varies between 25 and 500 ohm.
-no readable values between the first and the third.
I don't know which one is used by the guitar controller remote. I'll test "live". Maybe I can use only 2 pins.

As I said I will test many differents ways and I hope find the good
And I apologize "for my English" (I hope my message is understandable).

... I read again your message: if the potentiometer need only 2 pins (after my future tests and if it work), I'll try to solder it in state of the positive (or minus) button pin but I don't know if the potentiometer variation value can be used by the ATM?

And your message/picture were clear

Yan.