This project is a form of wearable electronic gadget that could be easily be used for personal use while working out or other activity measurement. This is a simple, do-it-yourself project that can be done by anyone with an interest in crafts or electronics! Donít worry, no experience with circuits is necessary for this project! Itís as simple as connecting wires from one place to another. Go ahead and give this project a whirl! Youíll have your own nifty wristband without too much cost or effort!
Step 1: Materials Needed
The following materials are needed for this project:
32u4 Microcontroller - Arduino compatible
Accelerometer -motion sensor
Lithium ion battery 3.7v
30 gauge wire - stainless steel thread
Foam - for wristband
This gesture controlled wristband is powered by an Arduino compatible microcontroller.
Our microcontroller for this project is Adafruitís Flora microcontroller. This microcontroller comes with an onboard power switch and a protected power supply, which we can connect with our lithium ion 3.7 volt battery. It uses a 32u4 microprocessor that has a built-in USB port, which can act like keyboard and other input devices by just connecting its USB connector to computer. This microcontroller can easily be used to design innovative
wearable gadgets. Itís pre-programmed but the usb connector can be used to reprogram the board when needed.
Step 2: Aligning Microcontroller
This section discusses the best way to align the microcontroller, pixel ring, and accelerometer on the foam wristband, as well as handle the battery and wires. These steps describe the process:
i. The pixel ring and accelerometer lay on the back of the microcontroller. Align the microcontroller inside the body of the constructed foam band and use a fine marker to mark the output pins on the foam band. This will be important so you can thread the wires through the band, making the band much more compact and making the wires much more organized and less annoying!
ii. Position the accelerometer in the middle of the pixel ring. Then use push pins (or another sharp
object) to puncture the markings and stretch out the holes to make the 30 gauge wire pass through it. 30 gauge wire is quite thin, so the holes do not have to be too wide.
iii. These wire threads will be used as wrapping wires to secure the microcontroller and the accelerometer in
iv. Pull the wires through to the edge of the wristband and band over the edge of microcontroller.
v. Use the wire stripper to strip the tips of the 30 gauge wires going through the edges. Strip off roughly 1/3 inch of the insulation from each end.
vi. Now secure the microcontroller in the body of the foam band by trimming the wire band over the
edges of the foam bracelet.
Step 3: Wiring Pixel Ring
In this section you'll wire the pixel ring to the microcontroller. It's pretty simple: just connect the wires just as shown in the circuit diagram. These are the steps to wiring these two components together:
i. Following the circuit diagram shown above, pass the 30 gauge wires through the pixel ring to the microcontroller ( i.e. input of ring connected to D10 connection of controller, ground to ground and Voltage of ring to battery source voltage of controller VBATT).
ii. Pull the wires down to secure the ring.
iii. Using wire stripper, strip half an inch off the end of the wire and cut the access wire.
Step 4: Assembling Accelerometer
Similar to the last section, this section discusses how to connect the accelerometer to the microcontroller. The connections are again shown on the above circuit diagram. Below are the instructions for this section:
i. Pass the wire through the appropriate connections (ground to ground, scl to scl, 3V to 3.3V and SDA to SDA) of the accelerometer and situate it in the band. Reference the circuit diagram above for the correct connections.
ii. Pull the wires down from the connection, bend and strip the access wire for proper connection. Once again, strip off about 1/3 inch of the insulation.
Step 5: Powering the circuit
In this section we'll discuss how to connect the battery to the microcontroller. It's a simple connection. These are the steps to connecting the battery and the microcontroller:
i. Connect the JST cable to the input power port on the microcontroller.
ii. Connect the other end of the JST cable to the on board battery connection, this will then reroute the power.
iii. Turn the microcontroller power on by pressing the black power button in front of JST connection port.
iv. Position the battery inside the circuit.
Step 6: Finalizing the wristband
This section discusses how to make the wristband on which all these components will be placed. These are the steps to creating the wristband:
i. Cut a 10 inch piece of foam to make the band. The piece of foam should be about 2mm thick. The piece should be about 2 inches wide.
ii. To make the band adjustable, we will use Velcro, or any hook and loop fastener. Position a 2íí long piece of the loop strip on one end of the wristband. Then, position a 2íí long piece of the hook strand on the opposite end of the wristband. If the hook and loop fastener has a peel off sticky backside, peel off the back layer and stick the fastener on the foam. If there is no sticky backside, use glue to connect the fastener to the foam band. You can now adjust the band to the width of your wrist!
iii. Place the circuit in the middle of the band. To connect the circuit to the middle of the band, glue the backside of the ring and accelerometer and stick the components onto the foam band, facing upwards. Glue the backside of the microcontroller and place it facing down on the underside of the foam band. Position the battery next to the microcontroller. Cover this section with another piece of foam. Tape the ends of that piece of foam to the wristband.
iv. The usb port in the microcontroller band can be used to reprogram the board if you want to.