From broken laptop to cool utility monitor

Art, Atoms, Electrons

Broken things are solutions looking for problems. They hold magic undiscovered potential. I hate throwing away broken things because I’m never sure I won’t be able to later re-purpose some part of them into something else. On a seemingly unrelated note, I’m often in need of plugging some random computer or video device in to a screen for testing and, up until now, I have had to swap cables on my desktop monitors or pull out some bulky crappy old monitor from the garage and find some temporary place for it while I use it. What I really want is a small lightweight monitor I can easily access and occasionally plug a Raspberry Pi or my linux server into, something that’s closer in size to a laptop screen than a big bulky desktop monitor and that will not take up desk space.

Cue in broken hardware

As luck would have it, my stupid cat likes to sleep on laptops. They provide a nice warm place and a soothing fan sound. Usually, the only repercussion of this fact is that I sometimes wake up in the morning with hair on the keyboard and the Google helpfully informing me that
In one particular instance however, I was using a hackintoshed Asus 1201N that was clearly not designed to support the weight of a house cat; I know because it never woke up from its night of feline suffocation. I took it apart to see what I could find but never did find the needle in that haystack; probably a shorted motherboard… In the closet of broken stuff it went.

A killer and his victim


I’m always thinking about creating different displays. I’m pretty bored with the standard monitor design and I’m always interested in challenges to the rectangle-in-a-sleek-shiny-enclosure status-quo which led me to learn that I could probably find hardware compatible with my broken laptop’s LCD panel. I took the laptop apart, got the part number of the LCD panel and eventually found the right board on ebay for about $30 (I searched for “HSD121PHW1 controller”, HSD121PHW1 being the panel’s model number). Two weeks later, the padded envelope with the telltale Chinese characters on it showed up in my mail mailbox and I immediately plugged it in to test it. Lo and behold, it worked!

From parts to a thing

Okay, so now, I actually have the parts I need to make that small monitor I’ve been wanting: a small LCD panel and a driver board I can plug any HDMI or DVI display into. The next step is putting it together in a cool, cheap and convenient way. I had been peripherally interested by Plexiglas for another project so I decided to try it as a mounting surface for this. I measured the width of the screen and driver board, as well as the height of the screen with and without the adjustment buttons, and got a couple pieces cut at my local plastic store (Santa Monica Plastics). I drilled some holes, mounted the various parts on the back using standoffs, and sandwiched them by screwing in the smaller piece of plexi in the front using longer standoffs.

Self Illuminating Responsive Tintype Frame

Art, Atoms, Electrons

The area of a tintype image that gets exposed to the most light essentially becomes a pure silver coating. While the reflective properties of silver make the final image a bit darker than traditional photographic prints, it also gives it a really compelling silvery metallic reflective feel. As a way to highlight those unique qualities, I decided to experiment with hiding LEDs in a box frame to illuminate the image from inside. I also wanted to find a way to intensify the lighting and make the image come alive as viewers got close to it.


I inherited some antique oak wood floor pieces and made quick work of it on the old chop saw.

I built some walls behind the front of the frame and attached some LED string lights on it.

I mounted an 8×10 tintype on a black backing board cut to fit at the bottom of the frame’s walls.

Lights OFF / Lights ON


The next step was to figure out the kind of sensor needed to make the lights come on as a viewer approached the frame. I figured the sensor required would need a range of at least a few meters and be able to return the specific distance to the closest obstructing object. I am not a distance sensor expert so I used the internet to help. In the end, I settled for a Maxsonar EZ0 LV. It’s cheap, it’s got a range of a few meters and it’s got both serial, analog and PWM outputs. I hooked it up to a teensy board and confirmed the sensor was returning appropriate distance values. On the lighting front, I was planning on controlling the brightness of the LED string with the teensy, but since the LED string requires a 12V supply and the teensy outputs only 5V, I used a MOSFET driven by the teensy’s output to modulate the LED’s power supply.

The electronically savvy amongst you will notice that I’m currently using 2 power plugs: a 12V one for the LED and a 5V USB supply for the teensy, which is stupid. I tried to use a voltage regulator to convert the 12V to a 5V supply but somehow it created much noisier reading on the distance sensor… I must have missed a capacitor somewhere. I will try using an Arduino Nano which can take a 12V supply directly.


God, I love the internet!!! I read somewhere that the sensor’s PWM signal was much cleaner so I started with that but I eventually found out that it also is much much slower and wasn’t able to keep up with the rate of change I was looking for. In the end, I used the analog signal and tried to filter it as best I could.

Using the Analog signal from a Maxsonar LV EZ0 to drive a 
12V LED strip through a MOSFET. 
Take 20 samples, sort and select the median value.

const int anPin = 9;
int anVolt, cm;
const int samples = 20;
int ranges[samples];
int highestReading;

float time;
float previousIntensity;
float maxDist;
float minDist;
int minVal, maxVal;

int mosfetPin = 9;           // the pin that the MOSFET is attached to

void setup()  { 
  // declare pin 9 to be an output:
  pinMode(led, OUTPUT);
  time = 0;
  maxDist = 450;
  minDist = 10;
  minVal = 5;
  maxVal = 255;
  previousIntensity = 0;

void loop(){
  // print time spent since last loop
  time = millis(); 
  // sample sensor value
  for(int i = 0; i < samples ; i++)
    anVolt = analogRead(anPin)/2;
    ranges[i] = anVolt;
  // convert to centimeters
  cm = 2.54 * ranges[samples/2];

  // shape the curve of the result
  float intensity = (cm - minDist)/(maxDist - minDist);
  intensity = 1-constrain(intensity,0,1);
  intensity = intensity*intensity;
  intensity = previousIntensity*.995 + intensity*.005;
  previousIntensity = intensity;

  // set the brightness of pin 9:
  float val= intensity*(maxVal-minVal)+minVal;
  analogWrite(mosfetPin, val);

//Sorting function
void isort(int *a, int n){
// *a is an array pointer function
  for (int i = 1; i < n; ++i)
    int j = a[i];
    int k;
    for (k = i - 1; (k >= 0) && (j < a[k]); k--)
      a[k + 1] = a[k];
    a[k + 1] = j;

Next Steps

Once I get my paws on that Arduino Nano board, I can rework my circuit and get the soldering iron out to make my electronics more permanent. I have also ordered a HC-SR04 Distance Sensor to see how it compares to the Maxsonar in terms of accuracy, speed and noise. Also, I need to make the frame a little bit deeper so the light can spread out a bit further across the image.

Which one is cooler?

The ominous cyclopean look or the cute and friendly Wall-E look?