### Learning Hot and Cold from Arduino

July 16th, 2010

Who needs Sesame Street when you can learn the same things from micro-controllers? Ok, I still need Sesame Street because life would be bleak without Big Bird. But I’m refreshing my elementary education through the use of my Arduino.

I found a thermistor in a box of parts. It looked like it came from an computer case and I wanted to see how it worked. A few resistors, a multi-colored LED, and some wiring later, I got it working with my Arduino Duemilanove. I haven’t played with analog sensors much so it was a nice little exercise for myself.

Overall its not all that complex, both in the circuit and the code. Though I was giving myself a big headache there for a while trying to find a fault that ended up being a coding error.

…Damn semi-colons… It’s always a semi-colon…

It’s okay though. That just made my victory all the sweeter when I finally got it working. I was able to entertain myself for a good 10 minutes moving the sensor from a cup of hot water to a cup of cold water just to watch the little light blink.

Here’s the code I used.
``` /*```

` `

`Hot and Cold sensor.`

` `

`Experimenting to get a thermistor to work that I found in my parts bin.`

`kamikazejoe`

`*/`

``` int hotpin = 13; // pin 13 lights the red light. int coldpin = 12; // pin 12 lights the blue light. int sensorpin = 0; // using analog pin 0 for the thermistor int temp = 0; // variable to store the value coming from the sensor void setup() { // initialize the digital pins as an output: pinMode(hotpin, OUTPUT); pinMode(coldpin, OUTPUT); digitalWrite(hotpin, HIGH); digitalWrite(coldpin, HIGH); } ```

``` void loop() { int temp = analogRead(sensorpin); // read value from pin 0 if (temp > 100) { // sensor reads an average of about 100 at room temperature. I used that for the comparison. digitalWrite(coldpin, LOW); // Turn off the blue digitalWrite(hotpin, HIGH); // and turn on the red. } else { // otherwise do the opposite. digitalWrite(hotpin, LOW); digitalWrite(coldpin, HIGH); } } ```

Here’s the wiring schematic for the LED and the sensor.

And a couple of pictures of it in action.

I never claimed I was going to do build anything useful.

### Bonding over Electronics.

July 12th, 2010

Took my younger brothers to show them Arch Reactor last night.  It was my attempt to get them interested in electronics other than video games.  I really didn’t expect them to be to interested in anything but the MAME cabinet that was there.  I figured it was still worth a shot and at the very least we get some brotherly bonding going on.

We arrived at the space and I found the Minty-Boost USB charging kit that I ordered had arrived.  I was eager to put it together so I roped in the help of my brothers.  I showed them my newly learned soldering skills, and awed them by melting metal to forge tiny electronics.  A bit of an overstatement, but I had to grab their attention somehow.

I showed the older sibling the techniques I had learned and he picked things up pretty quickly.  We started setting up the kit.  You could tell he was starting to have fun.  The word “awesome” was used several times.

The youngest, who’s only ten, got bored with his video games and wanted to see what we were doing.  At first he was intimidated by the concept of melting wire with a hot pointed stick.  Though he quickly got up the courage to give it a try.  The kid was a natural.  He picked things up very quickly and began out-soldering both his brothers.

I was so excited to see them having so much fun doing something educational and being constructive.  I wish I had thought to take pictures of them working, but I was more concerned they didn’t poke anyones eye out with the iron.

Piece by piece the kit came together.  It went together easily and the directions weren’t too difficult.  The  only hiccup was that the instructions covered multiple versions of the device, dependent on your power needs.  Eventually it was time to test it out. I grabbed the cable to charge my phone and viola!  Everything worked like it was suppose to.  Not only will this be a handy gadget, but a pleasant memory I get to carry around.

### SOLDERING! It’s the Future!

July 2nd, 2010

A couple of members at Arch Reactor teach an Arduino class. Of course the Arduino is a fantastic little micro-controller that everybody loves, but we aren’t here to talk about that today.

I’ve already been through the class the first time around, but this time they are focusing on a super-tiny variation called the Ardweeny. This time, instead of just buying a project board, the first class was soldering together an Ardweeny kit.

Soldering! I’ve been meaning to learn how to solder properly for years!

Turns out having the proper tools make a big difference. A dollar-store soldering iron isn’t good for much than burning yourself and tripping circuit breakers. However its helpful to have a good variable heat iron, third-hand armature, tip cleaner, rosin, rubbing alcohol, desk lamp, pink eraser, and a partridge in a pear tree bathing in your kitchen sink.

Working with an ideal setup I found soldering to be much easier than I expected. It may have just been the fumes, but ass I assembled my kit I began to find soldering a very zen experience. Knowing that the liquid solder flows towards the heat becomes your best tool. So keeping your heat at a single spot and not letting it radiate away through your armature or anything else conductive is helpful.

To my amazement, everything worked after only one attempt. As you can see from the lit LEDs in the photo, it’s alive… IT’S ALIVE! Mwahahahaha! I’m so proud of myself. I’m considering sending my finished kit to my mother so she can put it on the refrigerator.

### Arch Reactor Open House 2.0

June 16th, 2010

Arch Reactor’s last Open House was such a success we quickly outgrew the place we were renting.  It’s a great problem to have.  We have since moved to a new location that is better, stronger, and faster.  Now that we are setup in our new digs we are ready to celebrate.  This weekend, June 19th, we’ll be hosting Open House 2.0.  We have several presentations and demos to show off.  Come visit Arch Reactor at 2400 South Jefferson Ave.  St Louis, MO 63104.

### Pretty simple speaker mod

May 22nd, 2010

I’m aware how much I’ve been slacking when it comes to keeping up with new posts. I keep working on too many different projects at once and none of them get done. I thought if I got a quick little mod or two done, then maybe I can get back on track. Maybe some tunes will get me back into the groove.

I just so happened to have a pair of really nice Bose speakers sitting around and no receiver to wire them too. I felt this was a bit of a crime so I decided to do something about it.

I have a pretty basic iPod dock / radio that I’ve been using for an alarm clock for some time. It worked well enough, but I felt it could be better with really nice speakers. Though there was an AUX IN jack, there was not output other than the built in speakers. With a few alligator clips and some speaker wire I was able to correct that oversight.

It was a pretty simple process. Three screws towards the front let me remove the faceplate giving me the access I needed. Just following the two wires from each the left and right speakers let me identify the leads I needed to splice into.

With the wire stripper on my tiny leatherman tool I was able to push back the insulation and expose about 1/8 inch of metal on each wire.

I bundled my alligator clips together with a simple knot and attached them to the appropriate leads. Of course its best to keep them color coded to avoid confusion.

For the sake of neatness I used my Dremel tool to cut a small notch in the case. This let the clips dangle neatly out the side and allowed the case to fit back together nicely.

After that it was a simple matter of wiring up the speakers with speaker wire. I was a bit worried I would put too much of a drain on the built in speakers, leaving the whole setup far too quiet. I was pleasantly surprised with the results, however. It was much louder than I expected. There didn’t seam to be any loss at all, and it sounded great coming from those old Bose speakers.