Flashy Flounder

Length of Project:
Project theme:
Suitable for grades:
Tools & Materials
Material List
  • template print-out (full page - note the scale)
  • two sheets of felt fabric, different colours
  • 3’ stainless conductive thread
  • embroidery thread, colour of your choice
  • one 3V lithium coin battery (CR2016 or similar)
  • two 3mm LEDs in colour of your choice
  • ~six cotton balls
Tool list
  • black felt pen
  • scissors
  • needle nose pliers
  • needle
  • pencil
  • Optional

  • hot glue gun
  1. Use scissors to cut out the 8 shapes from the printed paper template.
  2. Trace the paper shapes onto the felt with your felt pen, tracing the “bottom” and “fins” onto one colour of felt, and the “top” shape in different colour. The “squeeze switch” pieces will be hidden and can be made of any colour.
  3. Cut the 8 felt shapes out with your scissors (TOP, BOTTOM, 2 squares, 2 donuts, 2 fins).
  4. Test your LEDs by fitting them onto the coin battery as shown. If they don't light up, flip the battery and try again. Only move to step 5 when you have determined that the LEDs work properly.
  5. Use black felt pen to colour each of the long LED wires BLACK. Leave the short wires plain.
  6. \Use pliers: bend and curl the LED wires as in the photo.
  7. Cut a 1 ½’ long piece of conductive thread, tie a knot in one end and thread your needle onto the other end. Sew everything in this step without cutting the thread. Copy the sewing line in the diagram: on the “BOTTOM” felt piece, sew the BLACK LED wires down with 3 tight stitches on each wire loop. Sew in a line to the tail base, then make several big, long hashtag stitches on one square felt piece. Finish with a knot on the square piece, then cut the thread end short.
  8. Use a new 1 ½’ piece of conductive thread to sew the second part of your circuit. Keep all your stitches at least ¼” away from the stitches from step 7; if they touch, you will create a short circuit and your LEDs won’t light up. Sew the plain LED wires on with three tight stitches on each wire loop, then sew in a line towards the tail. Make big hashtag stitches on the other square. Finish with a knot, and cut the thread end short.
  9. 8. Optional: run a line of hot glue along your conductive stitching lines to electrically insulate them, preventing any short circuits.
  10. Stack the felt donuts and battery between the squares as shown (square, donut, battery, donut, square). Arrange the squares so that the conductive threads poke out opposites sides so they don’t touch. Squeeze: if the lights don’t work, see the troubleshooting advice below to get them working before you move on to step 11.
  11. Use embroidery thread to sew the rest of the project. Stitch around the edge of the squares. Trap the battery and felt donuts inside.
  12. Sew the fins on the TOP piece as shown in the diagram.
  13. 11. Line up the top piece over the bottom piece. Use a pencil: feel for the LEDs below and mark their position on the top piece of felt. Next, poke the pencil through the fabric to make eye holes for the LEDs to protrude up through.
  14. Use embroidery thread to sew the TOP felt piece to the BOTTOM piece along the lines in the diagram, trapping the square in the tail. Start your stitching near the top of the fish. Before you sew it closed, stuff the fish with some cotton balls, then finish your stitching line.
  15. Sew mouth and gill lines as in the diagram. If you need to, you can sew “eyelashes” through all the layers to keep the top and bottom layers close, keeping the LEDs visible.
  16. Enjoy your new light-up buddy!
  17. TROUBLESHOOTING - do neither of the LEDs light up?

  18. Make sure that you use a fresh battery (you can check the voltage with your multimeter - it should be close to 3V)
  19. Try flipping the battery around.
  20. Check that the two conductive threads aren't touching at any point in your sewn circuit. Insulate stitches with dots of hot glue to keep them from touching, if necessary.
  21. Line the holes of the donuts up carefully; the big hashtag stitches need to be able to make contact with the battery on both sides.
  22. Does only one LED light up?

  23. It's possible that the one LED was sewn in backwards. Pull out all your conductive stitching and try again, making sure you mark each LED's positive (long) wire black with felt pen so you sew them both together with the same conductive thread.
  24. Test both LEDs with your multimeter on its continuity setting to make sure they still work.
Extension Challenges
  1. Use what you learned in this project to design your own LED light-up stuffy: you could use red, yellow, and green LEDs for a traffic light stuffy, make a stuffy boat model and give it red and green navigation lights, sew a red light-up heart patch on the chest of a bunny; have fun coming up with your own ideas! Make sure to sew your lights in “parallel”: one continuous conductive thread should connect all the positive (long) LED wires to the positive side of the battery, and a second continuous conductive thread should connect all the negative (short) LED wires to the negative side of the battery.
  2. Make a whole of other light-up ocean-themed felt creatures.
  3. Using the squeeze-switch design, add LEDs and a battery to light up a toque or t-shirt.
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