Make: Projects

Beating Heart Headband

Display your heart rate on a heart-shaped display.

Beating Heart Headband

This project is a collaboration with Jimmie Rodgers. Build a pulse-sensing headband that flashes a heart-shaped LED display to the beating of your heart! Uses a scratch-built perf board Arduino built from Mintduino parts, the Open Heart LED display, Yury and Joel’s pulse sensor, and a rechargeable lithium battery and power board. The circuit is built into a brocade headband with elastic at the back.

Steps

Step #1:

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Beating Heart HeadbandBeating Heart HeadbandBeating Heart Headband
  • Gather materials and tools.
  • Download the necessary Arduino code for the heartbeat headband.

Step #2:

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Beating Heart HeadbandBeating Heart HeadbandBeating Heart HeadbandBeating Heart Headband
  • Assemble the Open Heart display.
  • Further instructions on the Open Heart documentation page

Step #3:

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  • Build the Mintduino circuit on the enclosed solderless breadboard to start out, and fire up the Open Heart test code.

Step #4:

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Beating Heart Headband
  • Add the pulse sensor, load the headband's Arduino sketch onto the microcontroller, and test the sensor.
  • Be sure not to pinch the connectors on the back of the sensor's circuit board, just touch the side with the heart.

Step #5:

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Beating Heart HeadbandBeating Heart HeadbandBeating Heart HeadbandBeating Heart Headband
  • Dry fit the components onto a piece of perfboard.
  • Fit the heart display over the components, and mark the component layout with a marker.

Step #6:

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Beating Heart HeadbandBeating Heart HeadbandBeating Heart HeadbandBeating Heart Headband
  • Trim the circuit board to fit behind the heart display with a pair of shears.
  • Double check the fit by pairing the board with the display.
  • File the edges of the fiberglass perfboard to be smooth.
  • Wear a dusk mask!

Step #7:

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Beating Heart HeadbandBeating Heart HeadbandBeating Heart HeadbandBeating Heart Headband
  • Solder up the components of the perfboard Arduino, using component leads and small bits of wire to make connections as necessary.

Step #8:

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Beating Heart HeadbandBeating Heart HeadbandBeating Heart Headband
  • Headband time! Measure around the circumference of your head, then cut two pieces of ribbon to that length.
  • Thanks to Britex Fabrics for supplying the beautiful brocade and grosgrain ribbon for this project!

Step #9:

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Beating Heart Headband
  • Cut a piece of cord elastic about six inches long.
  • Tie the ends together in a square knot to make a loop of elastic.

Step #10:

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Beating Heart Headband
  • Line up the ribbons and use a zigzag stitch along the sides, but only sew together the ends of the ribbons, leaving the middle section open as shown.

Step #11:

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  • We'll connect the ends of the ribbon with the elastic to form the headband.
  • Fold and pin the ribbon ends to enclose the raw edge, and sandwich one side of the elastic loop in the fold.
  • Use this seam to hide the knot in the elastic.

Step #12:

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Beating Heart HeadbandBeating Heart HeadbandBeating Heart Headband
  • Stitch the ribbon seam around the elastic and repeat on the other side.
  • Now the headband is stretchy where it needs to be, and firm everywhere else to support the (non-stretchy) circuit!

Step #13:

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Beating Heart HeadbandBeating Heart HeadbandBeating Heart Headband
  • Wire up the sensor and power board and lay the circuit out on the headband to decide where the display will go.
  • When you find the spot you like, pierce the heart display's header pins through the outer ribbon of the headband and then through the perfboard. Solder it up.

Step #14:

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  • Stitch the power board in place, keeping in mind where the tiny lithium battery will go.

Step #15:

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  • Run the sensor out a small opening near the back of the headband, so it can loop around and clip to the ear.
  • Stitch down the wires so they stay put inside the headband.

Step #16:

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  • Use a zigzag stitch to sew the headband shut along the remaining open edges.
  • You may have to hand-stitch some spots too tight to get at with the sewing machine.
  • Leave an opening near the power board for toggling the power and changing the battery.
  • I used snaps to make a recloseable opening so I can show off the circuit.

Step #17:

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  • Install the battery and turn it on.
  • Attach the ear clip to the pulse sensor and try it on!

Step #18:

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  • Clip the sensor to your earlobe.

Step #19:

Beating Heart Headband
  • Congratulations, you're done!

Conclusion

Additional photography by Matt Richardson.

This project first appeared in MAKE Volume 29.

2 Responses to Beating Heart Headband

  1. Becky Stern on said:

    I used one of the tiny lipos from Sparkfun, like this one: http://www.sparkfun.com/products/9142

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