Introduction: SMARTBAND

Materials Required:

Base & Top fabric (black felt) (220 x 70mm)

Circuit fabric (black cotton) (210 x 60mm)

Conductive fabric


Conductive thread

Black non-conductive thread

A soft battery holder and a 3-volt lithium battery

Magnetic switches x 3

LEDs x 3


2mm black cable

Popper button

Equipment Required:

Sewing needle

Iron and Ironing board

Fabric Scissors

Laser Cutter

3D Printer (and black ABS plastic)

Sewing Machine


Hand Drill

Multi-purpose Glue

Step 1:

Laser cut pieces of fabric; two pieces of felt (the top with holes and the plain base) and one piece of cotton (circuit fabric to be sandwiched between the two felt pieces).

The computer templates are to be designed so that there are three sets of holes for 1) the LEDS 2) the magnets 3) the coloured felt indicators for the top layer.

Adjust the power settings to etch the circuit lines onto the cotton for the middle layer (circuit fabric).

Step 2:

Overlock all the edges of the cotton fabric to stop it from fraying.

Step 3:

Using fabric scissors, cut up three small pieces of felt; one red, blue and green. Glue these pieces to the inside of the top felt piece, directly under the three circles in the order green – blue – red.

Step 4:

Glue the velcro onto each of the felt pieces. The soft side should go on the right edge of the top piece and the hook side should go on the left edge of the base layer.

Step 5:

Using the sewing machine, load up the bobbin with conductive thread and sew the circuit lines onto the cotton fabric.

Step 6:

Using the remaining etched circuit lines on the cotton fabric, hand sew the soft battery holder into place (refer to Soft Coin Cell Holder for guidelines on making one of these). Hand sew the LEDs and switch magnets into place using the conductive thread, making sure the positives and negatives of all the components are correctly placed (the bottom of the battery holder is positive and therefore will need to follow the switches first and then meet with the positive sides of the LEDs. The negative side of the battery will need to be in line with negatives of the LEDs).


Step 7:

Insert a battery into the holder and test whether the circuit works.

Step 8:

Place the circuit fabric within the top and base felt pieces and mark where the popper button will go according to the location of the battery holder. This is so that the battery can be changed. Hand sew the poppers on using non-conductive black thread.

Step 9:

To ensure the circuit doesn't move around within the wristband, bondaweb the cotton fabric to the base layer of felt.

Step 10:

Design a case for the magnetic switch using SolidWorks. Create and print with black ABS plastic using the dimensions 11 X 15 mm. Glue the magnets into place.

Step 11:

Drill a hole into one of the short side edges for the black cable using a 2 mm drill bit. Cut a piece of black plastic coated wire (about 8cm long). This will be the cable that attaches the magnetic switch to the wristband. Glue one end into the hole of the case.

Step 12:

The final stage is to sew the top and base layers of felt together, making sure that there is a section left unsewn for the popper button and that a small part of the switch cable is inserted directly under the blue LED so that it is secured once sewn. Use a small straight stitch to ensure a neat, visually appealing finish.

NOTE: All soft components are available from the Kitronik webiste.