Lots of lovely PCB’s for the pattern synth! (finally)

ROHS compliant and ready for building, hopefully at a workshop i have planned, and a few for sale as finished units and kits.

this is something that i, and countless other people, have been working on for years now, but, as my experiments and hard work continue, i have found that 13 hours sleep, 3 bacon rolls with brown sauce and several cups of tea have done sod all to cure my hang over.

Guilherm asked to see a schematic for the IR sensors, so i’ve knocked a quick one up in Eagle for anyone else who’s interested. In the circuit, in its most basic form, the IR led is always on, connected to 5volts with a suitable resistor for the IR diode you are using in relation to the power supply.The IR sensor is connected in the same way, i found a 10k resistor worked in this case, but play arround with different values as it will affect is performance.

Both the IR led and sonsor should be connected to ground.

Between the resistor and the sensor, a jumper wire is connected to what ever you are using to read the sensor. This can be an analogue comparitor connected to an led circuit, or in my case in the videos below. an analogue input on the Arduino, either directly or via a demultiplexor.

Simple arduino code to read sensor and send to serial/USB.

void setup()
{
Serial.begin(9600);
}

void loop()
{
Serial.println(analogRead(5));
delay(20);
}

Simple Arduino code to read sensor and switch on an LED connected to Pin 8:

//works between 200 and 300 threshold with 5mm perspex.
//direct light triggers sensor and sensor only works with perspex when inverted, trigger = off.
int ledPin = 8;      // LED connected to digital pin 9
int analogPin = 5;   // potentiometer connected to analog pin 3
int threshold = 300;

void setup()
{
pinMode(ledPin, OUTPUT);   // sets the pin as output
Serial.begin(9600);
}

void loop()
{

if (analogRead(analogPin) < threshold) {
digitalWrite(ledPin, LOW);  // turn LED ON
} else {
digitalWrite(ledPin, HIGH);
Serial.println(analogRead(analogPin));
}

}

In this code, the led is switched on when the sensor value exceeds a certain reading, but could be adapted to dim an LED using PWM very easily. At the moment i have 16 sensors connected via two 4051 demultiplexor IC’s, connected to two analogue inputs on the arduino, and several digital pins to control which pins are read on the 4051. The Arduino then pumps the sensor readings out to a TI 5940 led controller as PWM signals to control the LED’s.

Hope this helps  Guilherm!

While trying to decide what to do with 10 of these 4052b demultiplexers I bought by mistake, I stumbled upon an interesting method of creating a squarewave step sequencer! Its perfect apart from the fact there are only 4 steps, but the method works, so 8 and 16 step versions should be no problem at all, even if it does involve a shed load of diodes…

The issue with these cmos oscillators is the fact they aren’t voltage controlled in the normal sense, so using the standard Baby10 style 4017 sequencer wasnt really an option, until now! So far I have a tempo control, four individual step pitch controls and a master tune control, all running off of 2 oscillators and a handful of components and IC’s.

I love these cmos IC’s, they are like Lego building blocks for noise!!!

Video to follow when i find the camera…..

It would seem my coding issue from before actually turned out to be a hardware issue, as the analogue demultiplexers I was using should have been 4051′s, not the 4052′s that i bought by mistake… Note to self: stop ordering things off the net while mildly drunk…

The other IC’s i tested were the 4067′s, which are 16 channels instead of 8. They work perfectly, but they are £1.40 a piece instead of 30p for the 4051 chips.Why, I don’t know, maybe there’s an army of pink elephants inside doing the work.

Also, as its been pointed out by Seb via email, capacitive touch sensors and the arduino can be configured for distance sensing, which is true and I played about with this with the Qprox chips previously, which I didnt make clear in the last post, but at the moment i’m still in favour of the IR sensors despite the one issue of ambient IR lighting conditions, which while this can be over come to an extent, strong direct light will create false positives.

But where’s the fun if everything was too easy? ;O)

So, following on from the LED clips below, I used the simple Arduino analogue read to Processing sketch to display the results of the IR sensors I’ve been playing arround with so that I have something to show you instead of a stream of numbers in the Serial Monitor. I’ve decided to use these instead of the capacitive sensors, as there are far fewer variables to screw up with the circuits when combined with the LEDS, and fewer components involved. when the sensors triggered i had them activating some LEDS, and you need to incorporate a few gound planes and extra capacitors to isolate everything. Cost and simplicity are the main factors her, so the IR sensors won in the end.

In the video you can see the graph line on the computer screen, as an object (not just my hand) draws closer to the sensors, the level of the graph drops. Its incredibly responsive!

Prepare yourself for some frantic and wobbly hand movements!

Despite my grumblings above, the Qprox  chips I tested were very useful, simple to wire up(although i use the dead bug aproach since they were surface mount chips), and surprisingly cheap as well. For anyone who’s tempted, the data sheets and application notes are very easy to follow for complete beginers and include a wealth of great tips to be able to get very stable circuits working quickly.

However, the IR sensors I made work out at pennies per unit to construct, and provide me with a whole host of features such as distance sensing and ambient IR light sensing which can be used to adjust the responsiveness of each unit of the whole matrix of sensors via the coding of the Arduino, and again, the simplicity of them is wonderful. By using analogue demultiplexers, you could string loads of them together into a few pins on the Arduino, only limited by the processing power of the MCU depending on what else you are doing with it.

There are comercially purchasable units for IR sensors, but these can easily cost £6 each and more, but with an IR source, IR phototransistor and a couple of suitable resisitors, this unit cost me £0.30, even cheaper when the components are purchased in bulk.

I’ll try and upload some more tests shortly once I can make them look a tad more interesting, although the 4×4 matrix of sensors and LEDS on my bread board are coming along nicely, just a few coding issues to iron out first before a public demo!

My friend Merv from Sleepmode has asked me to come up with some new toys for the band.

• Basically looking for a few of your synth tone generators/ gadgets; something with a filter, wave shape, lfo, etc if poss. Basically a noise generator. If it’s in key, would be important that I could tune the note, though doesnt have to have a keyboard. I need something to put an audio device through, like a sampler/ipod/geetar and then mash the noise up as much as poss.
  Ideally if we could fit it in a wooden case, maybe like a flat geetar case with felt insides(I think we have 1)as it would be getting toured up and down the country.

Now, knowing Merv, the more noise this thing makes the better, so this could be alot of fun!! On top of this and a few new boxes that Jamie Ball has commissioned, I’m keeping myself pretty busy at the moment.

I’ve been playing arround with ideas for an interactive touch screen LED surface for a while now, mainly using capacitive touch sensor’s and infra red proximity sensors, both of which are cheap and relatively simple to implement, especially on prototyping enviroments like arduino.

While the sensor stuff isn’t too exciting too look at just yet, since all I’m doing is reading the returned sensor data through the Serial Monitor, I thought I’d post up a sample of the LED matrix that the sensors will end up being used to control.

Grab yourself a beer and some popcorn, and prepare yourself for a mildly interesting video of a scrolling wave pattern… and then Conways “Game of Life”, which is a slightly modified version of of the example from Andrew on the Arduino forums.

Having scammed a free hospitality Ticket the night before, myself Keri and Fee headed up to Kinross for the 15th TITP.

Highlights had to be the Chemical Brothers on the friday night who were engulfed in one of the most amazing LED screens I’ve seen! My photos just didnt do it justice. Check out BBC Iplayer incase there are highlights of it, as the whole set rocked!

On the Saturday, Biffy and the almighty Rage Against the Machine were surely the best! I never thought I’d get to see Rage live, and unless you were there, you won’t! They requested the BBC didnt record any audio or visuals…. They were outstanding, and the set is permanently etched into my tiny, Tennents Lager riddled mind forever!!!

Sunday, Seasick Steve, who, for a man of his age puts any rocker to shame with his stage smashing abilities, and the old faithful Prodigy are again the best who stood out from the rest of my beer soaked memories.

ooooooh, Get Cape, Wear Cape Fly, he was good.

Reverend and the Makers too, but we only heard them, couldn’t get in the tent.

I’ve updated the page to include better step by step guides on how to bend this machine since so many have asked/complained… ;o)

See here >>>>