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The first step of my talking robot project – test whether this Speakjet chip works! Strangely, I couldn’t find much help on rigging up the demo/ test mode for the chip so here it is. I used a AA battery pack to power the breadboard and an LM386N op amp to hookup an 8? speaker to get sound out of the chip. The chip circuit is the demo circuit on the Speakjet datasheet and op amp circuit is the gain=20 circuit from the op amp datasheet.

The IR sensor fades the LED’s in and out and changes the frequency sent to the speaker.

The POT fades the blue LED in and out, increases/decreases the blinking speed of the green LED and changes the speed and frequency of the sound on the speaker.

This was part of a student lecture in the computation class. We discussed PWM and applying it to multiple LED’s and tri-color LED’s. Here’s pcitures and code for the 2 circuits I built and presented in class.

Multiple LED’s with PWM

Code:

int value = 0; // variable to keep the actual value<br /> int pins[] = {9, 10, 11}; // light connected to digital pin 9<br /> int numPins = 3;</p> <p>void setup()<br /> {<br /> // nothing for setup<br /> }</p> <p>void loop()<br /> {<br /> int i;</p> <p>for (i=0; i < numPins; i++)<br /> {<br /> for(value = 0 ; value <= 255; value+=5) // fade in (from min to max)<br /> {<br /> analogWrite(pins[i], value); // sets the value (range from 0 to 255)<br /> delay(30); // waits for 30 milli seconds to see the dimming effect<br /> }<br /> }<br /> int j;<br /> for (j=numPins-1; j >= 0; j–)<br /> {<br /> for(value = 255; value >=0; value-=5) // fade out (from max to min)<br /> {<br /> analogWrite(pins[j], value);<br /> delay(30);<br /> }<br /> }<br /> }</p> <p>

Tri-Color LED

Code:

// light connected to digital pin 9, 10, 11<br /> int pins[] = {9, 10, 11};</p> <p>void setup()<br /> {<br /> // nothing for setup<br /> }</p> <p>void loop()<br /> {<br /> // variable to keep the actual value<br /> int value = 0;</p> <p>//variables to check if fade in for a color is complete<br /> int fadedIn1 = 0;<br /> int fadedIn2 = 0;<br /> int fadedIn3 = 0;</p> <p>//variables to check if fade out for a color is complete<br /> int fadedOut1 = 0;<br /> int fadedOut2 = 0;<br /> int fadedOut3 = 0;</p> <p>//fade in blue<br /> if (fadedIn1 != 1){<br /> for(value = 255; value >=0; value-=5)<br /> {<br /> analogWrite(pins[1], value);<br /> delay(60);<br /> fadedIn1 = 1;<br /> }<br /> }</p> <p>//fade in green<br /> if (fadedIn2 != 1){<br /> for(value = 255; value >=0; value-=5)<br /> {<br /> analogWrite(pins[0], value);<br /> delay(60);<br /> fadedIn2 = 1;<br /> }<br /> }</p> <p>//fade in red<br /> if (fadedIn3 != 1){<br /> for(value = 255; value >=0; value-=5)<br /> {<br /> analogWrite(pins[2], value);<br /> delay(60);<br /> fadedIn3 = 1;<br /> }<br /> }</p> <p>//fade out red<br /> if (fadedOut1 != 1){<br /> for(value = 0; value <=255; value+=5)<br /> {<br /> analogWrite(pins[2], value);<br /> delay(60);<br /> fadedOut1 = 1;<br /> }<br /> }</p> <p>//fade out green<br /> if (fadedOut2 != 1){<br /> for(value = 0; value <=255; value+=5)<br /> {<br /> analogWrite(pins[0], value);<br /> delay(60);<br /> fadedOut2 = 1;<br /> }<br /> }</p> <p>//fade out blue<br /> if (fadedOut3 != 1){<br /> for(value = 0; value <=255; value+=5)<br /> {<br /> analogWrite(pins[1], value);<br /> delay(60);<br /> fadedOut3 = 1;<br /> }<br /> }</p> <p>}</p> <p>

I added switches to the fourth iteration of the passage of time. 1 rocker switch for on/off, 1 toggle switch which switches between 2 patterns, 1 momentary pushbutton switch that changes the pattern when the toggle switch is up. The switches are mounted on a separate short box with holes drilled using the dremel tool and attached to the bottom of the taller box. All the switches are hooked up to the Arduino using a breadboard.

Passage of time with switches from Bruce Drummond on Vimeo.

[gallery columns="2"] This is the first protoype of my computation project which should conceptually show the passage of time with light and be kind of a time piece. In it’s current state the green and blue LED’s are setup in a spiral layout. The loop begins with random LED’s going on/off and eventually builds to them spiraling inward together at an increasing speed each time, til they all disappear.

We were handed out Arduino’s and a bunch of other hardware in class today. It was pretty fun and easy setting it up. Later, I did a tiny experiment with a bunch of green and blue LED’s with the example blinking script, nothing fancy. I like the way it looks like a wiry mess. Looking forward to using this piece of hardware to build some fun, interactive physical stuff.

I’m really excited to be in Physical Computing this semester. The course covers basic electronics and microchip programming. We’ll be programming PIC chips, later in the semester and building all kinds of cool things. Really looking forward to that! It brings back some vague memories of physics in college and is sure going to consume a lot of my time. The first mini project was to build a circuit using a breadboard, a resistor, an LED, a switch and a 9V battery. It seems like I’ll be doing a lot more embedded systems programming this semester in Major Studio – Computation,  where we’ll be using Arduino, IR sensors and more. Here are some pictures of my first circuit!