LED Ampli-Tie with Flora
Make your necktie light up like a VU meter! This Flora project uses an Electret Microphone Amplifier to trigger 16 Flora NeoPixels sewn with conductive thread along the length of the tie.
Before you begin this project, we recommend reading the following guides:
Tools & Supplies
Bill of materials:
- 16 Flora NeoPixels
- Flora main board
- Microphone amplifier breakout
- Lipoly battery
- Scrap fabric for battery pouch
- 3-ply conductive thread
- Standard cotton/poly thread
- Ribbon cable or conductive thread ribbon
- Break-away or otherwise clip-on tie
- You’ll use a needle and to stitch up the circuit
- Sharp scissors are a must! You’ll also need a long ruler, some tailor’s chalk, and a seam ripper.
- Don’t forget your wire strippers, pliers, and flush snips!
- You will need a good quality basic multimeter that can measure voltage and continuity.
- Soldering iron and solder
Circuit Diagram
The Flora pixels are all connected to a common ground bus, as well as a common power bus connected to VBATT. The Flora pixel data bus is connected to D6. The microphone amplifier is connected to 3.3V, GND, and D9.
Battery Pouch & Flora
Use a piece of scrap fabric to stitch a small pouch for your lipoly battery. The pouch should be stitched to the back of the tie, just above where the Flora goes, and have an opening at the top for easy removal of the battery for charging. Use a seam ripper to open up the back seam of the tie just a little so you can thread the JST plug and wire inside the tie and down to the Flora.
The plug joins the Flora just inside the folds of the tie so it won’t get caught on anything.
Tack your Flora in place with plain thread by stitching some unused pads to the tie. Try to just stitch to the back surface of the tie so the front fabric remains smooth.
Sewing Pixels
Use a ruler to draw a line down the center of your tie with tailor’s chalk, and evenly distribute your 16 Flora pixels along this line.
Mark the position of each pixel with chalk.
Stitch a long length of conductive thread to GND next to D6, only piercing the back surface of the tie. Stitch over to the (-) pad on your first pixel and secure (but don’t cut the thread).
Add a few more pixels by connecting this long ground line to the (-) pads on the pixels.
Stitch the data bus from D6 to the input pad on the first pixel (marked with an inward-facing arrow). Tie off, seal the knot, and snip the thread.
Stitch small segments of conductive thread between each pixel, connecting the output of one pixel to the input on the next.
Check out my Conductive Thread guide for more tips on working with conductive thread!
Use another long length of conductive thread to connect Flora’s VBATT pad to the (+) pads on the pixels.
Once you’ve stitched a few pixels, test for shorts with your multimeter (make sure your long power and ground threads aren’t touching), and fire up the NeoPixel library test code to ensure your fledgling circuit is all good so far.
Stitch up the rest of the pixels – you’ll have one long ground bus, one long power bus, and short segments between each input/output data pads.
Add Microphone
To match the tie, paint your microphone amplifier with a little black nail polish.
Cut a piece of ribbon cable longer than the main part of the tie.
Peel off three wires to use with the microphone amplifier, which will live at the knot of the tie.
Insert the ribbon cable up through the inside of the tie. Cut a small hole with a seam ripper inside the knot of the tie and bring the ribbon cable through it.
Strip the ends of the wires and solder them up to the three holes on the microphone amplifier.
Use plain thread to anchor the mic to the tie knot using the large mounting holes.
Back at the Flora end of the board, solder the corresponding wires to 3.3V, GND, and D9.
The Code
You’ll need the NeoPixel library for this project. For newer Arduino IDE versions, select Library Manager, scroll to “Adafruit_NeoPixel” and install the latest version.
For very old Arduino IDE versions, download by clicking the ZIP button on the NeoPixel Github repository page, and rename the resulting folder “Adafruit_NeoPixel” and move to your Arduino libraries folder.
For more information on programming your Flora board including the software you need to do so, head over to the Getting Started with Flora guide.
We got so excited about this project we made TWO Arduino sketches to meter the volume in the room (by Phil Burgess, James DeVito, and Andy Doro). You can download them both at the LED Ampli-Tie Github repo. You can download the code from the listings below. The first dynamically adjusts to whatever volume is happening.
The second allows you to adjust the sensitivity of the VU meter:
Wear it!
Take your tie out on the town! It’s perfect for parties, concerts, weddings, Bar Mitzvahs…
If you need to wash your tie, remove the battery and gently spot clean– the pixels, thread, and Flora board can handle getting wet (then dry thoroughly), but water should not get in the microphone.