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Philips Hue Light Panel

Posted on September 20, 2022 by Miria projects 0

Since the beginning of the pandemic, I have been spending more time working from home. It quickly became apparent that the lighting in my work area was somewhat dark and uneven, which was causing me additional eye strain. To fix this, I wanted to add some sort of light panel in front of my desk that could provide even lighting over my work area. Ideally, I wanted something that would allow me to change the light color and brightness to suit my mood. Even better, I wanted something that could connect to my home automation system so I could integrate it with my current smart home setup.

I looked at a number of solutions but could not find exactly what I wanted. While there are large LED panels on the market today, most are ceiling lights that are intended to be wired directly into the electrical system. Another solution would be to position multiple lights in around of my desk, but this would take up space and could still result in some odd shadowing. As I couldn’t find anything I liked, I decided to build my own light panel using Philips Hue lightstrips.

For this project, I used 160 inches of Philips Hue color ambiance lightstrips (one base kit plus two extensions), although it would be possible to use any type of LED lightstrip. Although the Hue lightstrips are expensive, they seamlessly integrate with most home automation systems. They occasionally go on sale, so I was able to buy them for a decent price.

The first part of building the light panel was to figure out what type of enclosure to use. The enclosure needed to be deep enough to allow for effective diffusion of the lights inside. After some searching, I found an 18″ x 24″ shadow box with a 1.5″ depth, which seemed to be roughly the size I wanted.

The shadow box frame used four wood supports to anchor a sheet of glass in the front. I simply removed the staples from the sides and gently pried the supports from the frame, which allowed me to remove the glass. I then stripped the black lining from the side supports and painted them white so that they would reflect light inside of the frame. The backing board of the shadow box had a foam layer for pinning items to the back of the frame. This would not be ideal for mounting the lightstrips so I stripped off the foam layer and painted the board white.

The next step was to find the right diffusing material to use in place of the glass. I ordered samples of different light diffusing acrylics to see how they performed at the frame depth. Ultimately I decided on Acrylite Satinice White as the best diffuser for my purposes. I ordered a custom cut piece to fit the shadow box frame. Once it arrived, I slid the acrylic into the frame, glued the frame supports in with Gorilla Glue, and nailed some small tacks in for additional support. I then clamped down the supports and let the glue dry overnight.

The next step was to mount the lightstrips to the backing of the frame. I experimented with different methods of attaching the lightstrips to the backing board. I quickly learned that the Hue lightstrips are fragile and can break if you are not careful. My first strategy was to cut the lightstrips and re-attach them with Litcessory extension connectors so that the lightstrip segments would lay flat. This ended up being a costly mistake as the connectors were very finicky and would often not connect all of the pins correctly, which made chaining multiple segments very problematic. I then decided to leave the remaining lightstrips intact and simply zig-zag them on the backing board. This solution meant that areas of the lightstrip would not lay flat, which could result in uneven diffusion on the edges. I used hot glue to support the lightstrips in areas where they lifted off of the backing. I then covered the lightstrips with a thin layer of light diffusing fabric to even out the diffusion over the raised areas. Ultimately, this simpler solution seemed to be the best.

The last step was to drill a hole in the bottom of the shadow box frame so I could connect the Hue power cord. I then simply replaced the backing on the shadow box frame and hung my new light panel.

I am pleased with the outcome of this project. As it integrates with my home automation system, I can configure the light panel to match the ambiance of the room, change colors for specific notifications, or even to turn off as a reminder that it’s time to be done for the day.

Sound Sensitive Earrings

Posted on July 7, 2018 by Miria microcontrollers projects 0

I made these sound sensitive earrings as something blinky to wear while volunteering at the New York City Girls Computer Science and Engineering Conference. These earrings are a fun example of something interesting you can make with some basic computer science and electronics skills. This project is a mash-up of two Adafruit projects: the Gemma hoop earrings and the LED Ampli-Tie. They can easily be assembled in a few hours.

To start, you will need two Gemma microcontrollers, two NeoPixel 16 pixel rings, two microphones, two small rechargeable batteries, some wire, some jewelry findings, double stick tape, electrical tape and soldering tools. Make sure that you also have a charger for the rechargeable batteries. It’s also a good idea to paint the front of the microphone board black so that it blends in better with the electronics.

These earrings are assembled similarly to the Gemma hoop earrings with the additional step of attaching the microphone. First, start by attaching the LED ring to the Gemma. Connect the IN pin on the LED ring to the Gemma’s D0 pin and connect the LED ring’s V+ and G pins to their respective 3Vo and Gnd pins on the Gemma. Next, attach the microphone. It’s a good idea to place black electrical tape on the back of the microphone board before assembly to help prevent any shorts. Connect the microphone’s OUT pin to the Gemma’s D2 pin and connect the microphone’s VCC and GND pins to their respective 3Vo and Gnd pins on the Gemma. Be sure to run the microphone’s GND wire under the microphone so that the wire is concealed. Solder everything in place.Once the earrings are soldered together, it’s time to program them! I used a modified version of the Ampli-Tie sketch (available on the Adafruit site). I made a few minor modifications, such as changing the pins, removing the tracer dot, and adding a reverse mode so that the earrings can light up in opposite directions.

Next, attach the battery to the back of the Gemma with double stick tape. I also used a permanent marker to color the red battery wires black. Black electrical tape can be used to secure the battery and battery wires to the back of the LED ring and microcontroller.

Finally, attach the earring hooks to the LED ring. I simply attached small O-rings to the OUT pin of the LED ring and then attached the earring hooks with another small O-ring. And that’s it – turn on the Gemma and you are good to go! I found that my 150 mAh battery lasts for about four hours 🙂

DIY LED Strip Controller

Posted on September 6, 2014 by Miria microcontrollers projects 0

On a whim I decided to add LED lighting to my desk hutch. I already had a reel of LED strips but nothing to control them. As I wanted to build a controller that afternoon, I constructed it from parts which could be purchased locally. The controller I made has an on/off switch and two knobs: one to control the brightness and the other to control the color of the lights. Here is how I built it!

This project required the following parts: two 10K ohm potentiometers with knobs, an on/off switch, a project box, a 5 volt power supply, a power jack, some wire, and a small Arduino compatible microcontroller. RadioShack sells the Arduino Micro, but I used a Teensy 2.0 I had on hand as it is a much cheaper alternative. Of course, you also need some programmable LED strips. I used some 5 volt WS2812B LED strips (similar to Adafruit’s NeoPixel strips). It’s also useful but not required to have some connectors for the LED strips so that they can be detached from the controller. I used some JST connectors from my project stash.

The first step is to make holes in the project box. I did this with my trusty Dremel. Drill five holes: two for the potentiometers, one for the power switch, one for the power jack and a one for where the LED strip wires will enter the project box. Once the box is drilled out, place the power switch, potentiometers and power jack into the project box. Solder the power wires to the components.

Next, I assembled the LED strips. If you are adding connectors to the LED strips, solder those on to the strips. If you’re connecting multiple strips, be sure that you bundle the wires together properly. I’ve found that using colored wire or marking wires with different colors of tape makes it easier to keep everything straight.

Next, solder the potentiometers and LED strips. Mark the data lines for the LED strip and the potentiometers so you know which wire corresponds to a given component. It makes coding the microcontroller easier.

Next, solder the microcontroller. Keep track of the pins and their corresponding data lines. When soldering the potentiomenter to the microcontroller, make sure to connect the potentiometer data wire to pins that can support the analogRead function. These pins generally begin with the letter ‘A’.

Now it’s time to program the microcontroller. The simple code can be found here. Update the code to reflect the length of your LED strip and the pins that correspond to your components. Be sure to test everything!

Once you’ve verified that everything works, tape up any solder joints so that there are no shorts. Close up the box and you’re done!

Pulse Jacket

Posted on January 17, 2014 by Miria microcontrollers projects 18

This was one of my first Arduino projects. After some near misses with bicyclists while running at night, I decided to get some lights so people could see me in the dark. But why stop at boring plain lights? Wouldn’t it be cool if they could respond to my heart rate?

I looked at a number of existing heart rate sensors for Arduino, but most were optical and could not get accurate readings while I was running since they were constantly being jarred. Since I run with a Garmin GPS watch and heart rate monitor, I tried to hack into the information being sent between the heart rate monitor and the Garmin watch.

Reading a bit more about the technology, I learned that Garmin used the ANT protocol for communication between the watch and heart rate band. The good news was that SparkFun made an ANT transceiver breakout board. The bad news was that the board was discontinued and I could only get my hands on one board. I decided to move forward with this board for prototyping knowing that I would need to come up with a different solution when I made the final project.

The first step was to get the Garmin heart rate monitor and an Arduino communicating with each other. The ANT protocol documents are pretty thorough and they make great bedtime reading. Fortunately for those of us who are impatient, this thread on the SparkFun forums has sample code that already implements the protocol for the Garmin heart rate monitor.

Now that I had the pulse rate information, it was time to add lights. I am a huge fan of Adafruit’s LED strips. These strips have weatherproofing so it would be possible to run outside in the rain. I trimmed the strips to the length of my arms and sealed the ends.

I added seven different light modes which increased in speed with the heart rate: rainbow, raindrop, range pulse, color shot, twinkle, circulatory and Cylon. Most of these modes are self-explanatory. The range pulse mode faded the strips in time with the pulse and also chose the color based on the current pulse rate (blue being low pulse, red being high). Here you can see a quick demo of the seven modes:

I then began building the final version. For this, I chose to use a Teensy 2.0 because of its low price and small size. I also had to revisit the ANT transceiver. Searching around, I found this ANTAP281M5IB module with an on-board antenna. After some very delicate wiring and soldering, this proved to be a direct replacement for the SparkFun board.

Once everything was working, it was time to put this into a portable package for running. The main concern was power. After a bit of research, I found these Energizer power packs that I could plug directly into the Teensy. The one amp power pack would power both LED strips for about an hour. After verifying that everything still worked, I placed the assembled project into a small project box.

The last issue was how to attach the LED strips to my arms. I thought about embedding them into a jacket by sewing them in, but I decided against that as it would be a pain to clean. Finally, I just glued some cable clips to the back of the LED strips and used velcro straps to adjust them for the right fit.

And after all that we were ready to go! My first real-world test was the Midnight Run in Central Park on New Years Eve 2013.

And now I can easily be seen in the dark!

DIY Night Vision Camera

Posted on September 22, 2013 by Miria projects 0

I found this Instructable about how to make your own night vision camera. It seemed to be a fun project, so I decided to give it a try.

The first step is to remove the infrared (IR) filter from the camera. I broke my first camera attempting to do this. I was far more careful with my second one and successfully removed the filter. The little blue chip is the IR filter:

This is how the photos look with the IR filter removed:

After successfully removing the filter, the next step was to build an IR LED array to be used as a light for the camera. With a little bit of help, I was able to laser cut a perfect array of holes for the LEDs. Following the instructions, I assembled the LED array and turned it on, only to be disappointed by an incredibly dim light.

What went wrong? Here’s the point where I confess that I am relatively new to electronics, and so there are certain lessons that are yet to be learned. I wired the LEDs incorrectly. I got a second batch and wired them together.

And still the array was too dim. It was time to really understand how the circuit of the array worked. There was something more at play here. I found a really cool LED array calculator online that helped me get to the bottom of my problem. I had to examine the LEDs more closely. The instructions use infrared LEDs from Radio Shack, which have a 940 nm wavelength, a 100 mA forward current and a 1.28 volt forward voltage. My first two attempts used LEDs that had a forward voltage of 1.5 volts, which meant that the LEDs were not getting enough power. I ordered a new set of IR LEDs with a lower forward voltage of 1.2 volts and assembled the array for the third time.

The third attempt was better. With the new array, I was able to capture photos in the dark!

I did a little test to get a feel for how well the camera worked. First, I set up a small scene to photograph. I was interested to see how the camera could capture color and detail. Here is the control photo, taken with my normal camera:

First, I took a photo with the lights on. The room was somewhat dark, so the photo did not come out very clear:

Next, I took a photo with the lights off, about one foot away from the objects. The detail was still somewhat clear, although differentiating colors was not really possible.

The second photo was taken from two feet away. At this point, some objects are no longer visible.

The final photo was taken from three feet away. The objects are almost imperceptible at this point.

Although it was fun to build this, it isn’t very practical for real-world use. The major problem seems to be the power, as the 9 volt battery drains very quickly and is not strong enough to power many high-power infrared LEDs. If I go back to this project, the first step would be to build an array with a larger power supply and brighter LEDs. In the interim, I will just have to be content with taking nighttime pictures of things up close.

Blinky Box

Posted on July 4, 2013 by Miria microcontrollers projects 25

This was a gift for my two year old nephew. Since he is a fan of lights and buttons, I wanted to make something blinky for him to enjoy. The concept was simple: make a clear box with buttons and lights that would change color and pattern based on the buttons that were pressed.

First, I had to find a clear acrylic box large enough for some LEDs, switches, buttons and a microcontroller. I found this great polycarbonate box from Hammond Manufacturing that seemed to be the right size. Next, I needed to find some buttons that could take a beating. Fortunately, Adafruit sells some translucent arcade buttons in bright colors. The lighting was a no-brainer as I am a huge fan of Adafruit’s addressable LED strips. I also found a glowy on/off switch for the power. Somewhere along the way, I thought it would be a cool idea to add a rotary knob so that he could select different blinking patterns.

The next step was to assemble the pieces and wire everything together. The polycarbonate box was harder to work with than I had hoped. The polycarbonate would discolor if I used the laser cutter, so I found myself drilling all of the holes with a rotary tool. I then added the buttons, knob and on/off switch.

Once all of the bits were together, I had to add a microcontroller to control the button states and light transitions. I decided to go with the Teensy 3 as it was what I had on hand (and I had yet to work with one). Also, Teensy 3 allows all digital pins to be interrupted (as opposed to four on the Teensy 2), which would simplify reading the button state. The other great reason for selecting the Teensy is that it already has an Encoder library, which makes reading the knob state simple.

The code was easy. Interrupts on the arcade buttons would change a variable representing the color. The interrupt for the black button would kick off a rainbow display routine. In the main loop, I polled for changes in the rotary encoder state and transitioned the lights accordingly. When I was finished, there were five main light colors (white, red, yellow, green and blue), one rainbow routine and six possible blink patterns (always on, fade on/off, blink on/off, chasing light, random twinkling lights and alternating lights).

I saved the hardest part for last: power. I wanted something that my nephew couldn’t disturb, so anything outside of the box was out of the question. Regular batteries would require opening the box to change, so I thought something rechargeable would work better. I decided to go with a Lithium Ion battery. Unfortunately, these are generally around 3.7 volts and the LED strips require 5 volts. This meant that I needed to find a way to recharge the battery from the outside and find a way to step up the voltage. Fortunately, SparkFun sells a power cell board that does both. Yay!

I added a power jack to the box and used an old 5 volt AC adapter to supply the charging power. I then connected the power cell board and the battery using this handy tutorial. Fortunately, the charging of the battery seemed to work! Unfortunately, the power cell board only provides 600 milliamps at 5 volts, which is not enough power to run a full meter of the LED strip. Sadly, I had to cut the strip in half. It was still impressive even with just one loop of lights! To make the battery last even longer, I also implemented some of the suggestions for conserving power with the Teensy.

The best part about this toy is that it is fully programmable. As he gets older, I can program new features or games into it. Perhaps one day, I can even teach him to program it himself! 🙂

Here is a short video of the assembled box

Motion-Sensitive Paper Lantern

Posted on June 25, 2013 by Miria microcontrollers projects 0

Back in February, I made a motion-sensitive lantern for the Lunar New Year. The idea was simple: have a lantern that appeared to be mostly plain but would reveal a design when a person moved closer to it.

The easiest form to use was a round paper lantern. I started with a 14″ white paper lantern and some markers. I then attempted to draw some snakes on it, as 2013 is the year of the snake. As I am not an artist, let’s pretend that these squiggles look like snakes.

The next part was to add some lighting. The lighting needed to change color. I decided to go with LED strips from Adafruit, as I could wrap them in the center of the lantern and have fairly uniform lighting. I had some left over pieces from a previous project and this seemed like the perfect occasion to use them.

Next, the lighting needed to respond to motion. There were a couple of sensors that would have allowed me to detect motion, but I decided on a passive infrared (PIR) sensor. Interestingly, these sensors work by detecting rapid changes in infrared radiation (including those given off by body heat).

The code for this was very straightforward. The PIR sensor sends a high signal on its output pin whenever motion is detected. Therefore, it’s as simple as polling the output pin with digitalRead() and transitioning the lights based on changes in the output pin state.

Finally, I had to find a lightweight power source. I found an Energizer power pack, which was the perfect power supply for Teensy. It even came with a mini USB adapter, which meant that I could plug it directly into the Teensy without having to solder anything. Here is the final internal assembly of the lamp!

And here is the lamp, fully assembled and running!

led