Category: Projects

Building an array or grid of leds from Neopixel strips?  You might want one of these little boards I’ve come up with.  Here is a video (terrible) of me soldering together a few strips into a 3 x 42 array.  I found them to reduce the time and mistakes made when using individual wires.

 OshPark is where you can oder the boards.

Questions?  Please email me (ian @ mcyork.com)

I was talking with a friend who has a big problem.  His son can’t use a keyboard but loves to play computer games.  He can only use a mouse and only with his right hand.  He has very limited abilities in his left.  It became clear after our conversation that if we put our heads together we could make something that might enable him to play the different computer games with more ease and enjoyment.

New video link added at the end of this posting.

We imagined a joystick that could be used to maybe send different keystrokes to the keyboard via some device.  I took this problem home and below is what became “the keyboard helper”.

The Leonardo has a great capability; It can emulate a keyboard and mouse.  Using this as the core of the new device I tested a number of code snippets   I was able to send words and keystrokes to Notepad, what fun!  The next thing was to read analog ports connected to a joystick.  There are a ton of examples on the web, I got this running quickly.  To wire up the joystick I needed to tie in some resistors.  I’ll try to explain why they are on the circuit later.  The last part was to add an LCD display for some visual feedback.  I thought it would be important and we found out after the fact that it ended up having a very different function than what I had first envisioned.  LCD displays can be hooked up in a few different ways the most common are parallel (all pins) or via some type of intermediate device that you to talk to via a serial or i2c interface.  I had an i2c to LCD kit from an old project and decided to re-use this (the link is to a more recent iteration).  The LCD display itself was pulled out of an old PBX phone, it had some odd pinouts but normal LCDs you find on the web will be simple to wire up.

On a 2 hr flight, I crafted most of my notes on how I felt the “system” would work.

I’d present a grid on the 2 line display of the characters Q W E R.

________Q__W______

________E__R_______

Something like the above. When you tell the LCD to use a blinking cursor and then move to a position on top of a letter – it looks selected.  By moving the cursor over each letter as the joystick moves – you can see what letter is available to be typed to the computer.  Great visual feedback.  In the above diagram suppose Q is high lighted.  The movement UP or LEFT on the joystick would then send the letter Q to the keyboard.  A movement DOWN would select E but not send E.  Once on E a movement LEFT or DOWN would send E to the keyboard.  Scroll to the letter needed then move -off- the screen to send it to the computer.

That’s how the 1.0 version functioned. There was some immediate feedback as the game being played changed.  It would be preferred to hold the key down and not just type one letter.  Selecting the letters became less critical as now it was a matter of just holding down the key and there were only 4 to send.  Here is the resulting logic main loop of the program that shows this modified approach.

void loop()
{
 center = 1; 
 up = map(analogRead(0),0,1023,0,1);    // Q MoveTo(0,9); 
 left = map(analogRead(1),0,1023,0,1);  // E MoveTo(1,9); 
 down = map(analogRead(2),0,1023,0,1);  // R MoveTo(1,11);
 right = map(analogRead(3),0,1023,0,1); // W MoveTo(0,11);

 if (up) {
 Keyboard.press('q');
 MoveTo(0,9);
 center = 0;
 }
 if (left) {
 Keyboard.press('e');
 MoveTo(1,9); 
 center = 0;
 }
 if (down) {
 Keyboard.press('r');
 MoveTo(1,11);
 center = 0;
 }
 if (right) {
 Keyboard.press('w');
 MoveTo(0,11);
 center = 0;
 }
 if (center) {
 Keyboard.releaseAll();
 MoveTo(0,0);
 }
}

The letters are now being sent as lower case. What’s nice about this approach is the MAP function.  It has a lot of uses.  Here it converts the range 0 to 1023 into the range 0 to 1.  This enables the code to read both momentary switch type joysticks or analog potentiometer joy sticks (we’ve used both in our prototypes).

Mental Note: if two states are on at the same time does the keyboard function send both or does the last one sent win?  Think to move on a diagonal in a game and how the code above may or may not enable this.

I am working on a wiring diagram it is going to be a while until I either build a second version or I can borrow back the one I’ve built for a day to recall the exact details.  Like I said above – examples for each element of this are easy to find on the web – you should not have much trouble.

A working version of the code (assuming you use the right pins with your LCD and such) is here.  As my LCD and I2C are probably different from yours – there will need to be some adjustments in the commands sent to the LCD (maybe).

I liked this project for a number of reasons.

1. Jerry is a much happier camper now. UPDATE BELOW
2. I had no idea how great that would make me feel.
3. Game control is vastly improved.
4. The project was small in scope and I was clear on the goal.

Thank you for reading.  There is not too much more to say about this project at this time.  It will be a while but the circuit will be doodled up some day.

Go make stuff.

The LCD took on an unexpected use:  It happens that the joystick needs to be positioned just right.  Exactly right.  Such that the limited motion of the left hand can move in the 4 directions.  It takes some time to get this center point just right.  The LCD will be highlighting the direction of the “problem” and my friend can use this as visual feedback until he gets both the joystick and hand centered.

UPDATE. The fine film crew at work put together this video of the project’s impact.

I am working on 1000 projects all the time.  You may already know that of me.  This one will be a fun adventure.  I’ve started by shrimping.it this is a site where they show you how to build a bare-bones Arduino.  I went and ordered the part for 4 kits via the electronics seller http://www.taydaelectronics.com/ it was under $30 for all the parts I needed.  I did not get boards as I plan to design my own at a later phase.   Here’s the shrimp built with an 8 pin chip holder where it can be used to program the little chip.  This is an Atmel ATTiny 85 ready to be programmed.

Now the hard part.  Let’s say I want to program a lot of these little chips.  Wouldn’t it be nice if the Arduino held in memory all the code and capabilities to program the chip without an attached USB link to a computer?  That’s goal #2.

Here is an ATTiny 85 running code that was pushed through the Arduino in the traditional manner (Goal #1).  What I like about the Tiny line of chips is there is little to no supporting hardware required to have them run.  This makes them a lot of fun for all kinds of little builds.  They will even run off three or 4 AAA batteries and for quite some time.

The original StockBot was built on the Netduino platform.  I’ve been working on the code for the Arduino platform and have now assembled working code.  I can’t claim it is stable yet but it’s doing the job for now.

I am using the Ethernet Arduino.  As I explore a number of things all the time, I have also made a shield for the Arduino to see if this project could become a kit for others to build.  A little stuck on a source for Numitron tubes so I am trying to make the board generic enough to take a tube or a normal led display (still puzzling that through).

Let me clean up the code – I’ll take a hard look at it over the next month.  Maybe after the skis hit the slopes in Whistler I’ll have something to post and walk everyone through. Early December if you don’t ski or board.

What’s StockBot – here’s the beginning post

Here are the prototype boards I had made.  They have a nasty bug but I learned something (and could fix it so all is good).

This is the page that allowed me my “Eureka” moment on how to drive a large number of outputs from a very few number of pins.  If you ever wished you could have 10 or a 100 more output pins – the shift register chips are ones to consider.  I won’t blabber on just follow the link watch the video and you know where to start if it can be applied to your own effort.

http://bildr.org/2011/02/74hc595/ 

Enjoy