Team Punch Through: Punch Through

Published December 21, 2015 © MIT

Smartphone controlled mood light

This tutorial teaches you how to make a mood light that you can change color and intensity of using your iPhone.

AdvancedFull instructions provided3,320

Things used in this project

Hardware components

Punch Through LightBlue Bean

Adafruit NeoPixel Ring: WS2812 5050 RGB LED

Resistor 2.21k ohm

Resistor 10k ohm

General Purpose Transistor NPN

Globe Lightshade

Hand tools and fabrication machines

Soldering iron (generic)

Drill

Hot glue gun (generic)

Wire Stripper

Knife

Story

Introduction

LightBlue Explorer's offers some features that enable you to test devices. However, with the Bean, LightBlue also offers a view that can interact with the connected Bean.

Software

* LightBlue App

* Bean Loader App for iOS

Hardware

* LightBlue Bean

* iOS device

How to Build the Mood Light

Step 1: Get the parts

Material:

A LightBlue Bean
A 16 LED NeoPixel ring
A 3.3V voltage regulator
A 2.2 kΩ and a 10 kΩ resistor (both a part of this resistor kit)
An NPN transistor (2N3904)
A globe light shade
Foamcore
A USB cable
Wires

Tools:

Soldering iron
Drilling machine
Wire stripper
Hot glue gun
Knife

Step 2: Solder the voltage regulator

We will power the mood light with a 5V USB cable. The Bean runs on ~3V, so to step it down we will use a voltage regulator.Solder the voltage regulator onto the perfboard of the Bean to the holes below A1 and facing down. Make sure that you put it in the holes below A1, not in A1 itself. Cut the legs sticking out with a pair of pliers.

Take a bit of black wire and solder it from the top pin of the voltage regulator to GND on the Bean.

Take a bit of red wire and solder it from the middle pin of the voltage regulator to BAT on the Bean.

Flip the Bean over and solder bridges between the top pin of the voltage regulator and the black wire and the middle pin and the red wire.

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Step 3: Solder the transistor

The transistor will be used as an amplifier to step up the Bean’s signal from 3.3V to 5V for the NeoPixels.

These are the pins of the 2N3904 transistor we use in this tutorial:

Solder the transistor with the emitter pin through pin 5 on the Bean, the base pin two holes down and the collector one hole down from the base pin. Cut the legs sticking out through the back.

Step 4: Solder the resistors

Take the 2.2 kΩ resistor and solder it between the middle pin of the transistor and the middle pin of the voltage regulator.

Take the 10 kΩ resistor and solder it to the bottom pin of the transistor and the bottom pin of the voltage regulator, one hole away from the transistor.

Flip the Bean over and solder a bridge from the 2.2 kΩ to the middle pin of the transistor and the other leg to the middle pin of the voltage regulator. Solder a bridge between the 10 kΩ resistor and the bottom pin of the voltage regulator but leave the leg by the transistor.

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Step 5: Solder NeoPixels

We will control the NeoPixels from pin 5 on the Bean. The signal will be amplified through the transistor and coming out through the collector pin. Solder a yellow wire from IN on the NeoPixels and to the collector pin on the transistor (the bottom one).

Take a piece of black wire and solder it to GND on the NeoPixels and GND on the Bean. Solder a red wire from VCC on the NeoPixels and to the hole under the to the bottom leg of the voltage regulator.

Flip the Bean over and solder a bridge from the bottom pin of the transistor to the yellow wire to the leg of the 10 kΩ resistor.

Solder a bridge from the red wire to the bottom leg of the voltage regulator.

Step 6: Drill hole through light globe

To pull the USB cable through the light globe we need to drill a hole through its neck.

Use a drill with the same diameter as the USB cable and slowly drill a hole through the neck of the light globe.

Step 7: Cut the USB cable

Cut the end of the USB cable that doesn’t go to the wall socket/computer. Strip about an inch of the wire and remove the foil. The USB cable we used is an USB 2.0 that is used to program Arduino UNOs. It has four wires in it: red, black, white and green.

We will only use the red and the black wire, so tape the rest to the side of the cable.

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Use the wire stripper to strip the tips of the red and black wire. Put the USB cable it through the hole we drilled in the light globe’s neck.

Solder the red wire next to the red wire from the NeoPixels and the black wire to the top leg of the voltage regulator.

Flip the Bean and solder bridges so that the red wire is connected to the bottom leg of the voltage regulator and the black wire is connected to the top leg.

Now the Neopixels will be provided with 5.0V from the USB cable and the Bean with the stepped-down 3.3V from the voltage regulator. The Bean is ready to go!

Step 8: Cut bottom plate

We will use foamcore to make a bottom plate for the lamp.

Put the light globe on the foamcore and press it down so that you get the outline of the neck.

Use the knife to cut out the inner circle. To avoid making the edge rugged, first cut the top layer of the foamcore, then the inner layer and last the bottom layer.

Use the hot glue gun to glue the Bean to the foamcore.

Place the bottom plate in the neck of the light globe and put glue along the edges of the plate.

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Step 9: Upload Sketch to Bean

We wake the Bean up whenever it is connected and check the color of the on-board LED once a second. Whenever the color has changed, we will set the NeoPixels to the same color.

Upload the code below to the Bean.

Step 10: Open LightBlue

To open the LED view in your LightBlue app:

Connect to a Bean.
Select Options in the upper-right corner.

To set the color of the Neopixels, we will use the iOS app LightBlue. It has a demo screen where you can set the color of the Bean’s on-board LED.

Open the app LightBlue, connect to your Bean and change the LED color and intensity on the demo screen. You’ve just made yourself a smartphone controlled mood light!

Troubleshooting

Having trouble with this guide? Reach out to BeanTalk to get directed feedback from our developers and community!

Code snippet #1

#include <Adafruit_NeoPixel.h>
// The pin that is connected to the NeoPixels
#define PIN 5
// The amount of LEDs in the NeoPixels
#define NUMPIXELS 16
// LedReading is the type we get when we call Bean.getLedValues();
// For example, to get the amount of red in the Bean's LED,
// we use ledColor.red to get a value from 0 to 255
LedReading ledColor;
// previousLedColor will be used to check if the LED's color has changed
LedReading previousLedColor;
// Set up the NeoPixel library
Adafruit_NeoPixel pixels = Adafruit_NeoPixel(
  NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  pixels.begin();  //  Initialize the NeoPixels
  Bean.enableWakeOnConnect(true);
}

void loop() {
  if(Bean.getConnectionState()) {
    ledColor = Bean.getLed();
    if(ledColor.red != previousLedColor.red ||
      ledColor.green != previousLedColor.green ||
      ledColor.blue != previousLedColor.blue) {
      for(int i = 0; i < NUMPIXELS; i++) {
        pixels.setPixelColor(
          i, pixels.Color(ledColor.red, ledColor.green, ledColor.blue));
        pixels.show();
      }
    previousLedColor = ledColor;
    }
  }
  else {
    Bean.sleep(0xFFFFFFF);
  }
}

Credits

Punch Through

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We’ve been building connected products since 2009. Our diverse team has expertise in every layer from hardware to software to web.

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Smartphone controlled mood light

Smartphone controlled mood light

Things used in this project

Hardware components

Hand tools and fabrication machines

Story

Introduction

How to Build the Mood Light

Step 1: Get the parts

Step 2: Solder the voltage regulator

Step 3: Solder the transistor

Step 4: Solder the resistors

Step 5: Solder NeoPixels

Step 6: Drill hole through light globe

Step 7: Cut the USB cable

Step 8: Cut bottom plate

Step 9: Upload Sketch to Bean

Step 10: Open LightBlue

Troubleshooting

Code

Code snippet #1

Credits

Punch Through

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