Introduction: Personal Space Belt

I have always felt that, as someone who is perceived as female, my personal space is often invaded by men. This male entitlement to female bodies is, of course, a critical part of feminism, and I wanted to both draw attention to this fact and help women in unsafe spaces feel better about their safety. In order to do this, I created a personal space belt.

This is, of course, only the prototype- the full version will be far more advanced and have many more features, but as a prototype, this is merely meant to show others the basics of how it will work and help me decide on more expansive and difficult concepts to add.

Step 1: Gather Materials



Distance sensor

6 different colors of wire (red, black, green, blue, yellow, white)

16 LEDs

4 green, 8 red, 4 yellow in this example, but colors can change

Arduino UNO

Shift Register

Blank circuitboard

Fabric (approx 1 sq ft)

16 220 ohm resistors


Soldering iron


Wire cutters

Wire strippers

Electrical Tape

Breadboard (3) (for component testing)


Basic soldering

Intermediate programming in C/C++

Step 2: Test Materials

Create a test shift register board to make sure that all of your components work properly. A good tutorial is available at the Arduino website here, but I'll walk you through it anyway.

Firstly, attach the shift register to your breadboard- this might mean bending the pins a bit, but that's okay. The small lip should be at the top of your breadboard. Then, attach a positively charged wire to the seventh pin down on the right side, and a negatively charged wire to the eighth pin down on the left side (the positively charged wire should be connected to the 5V port on the Arduino, and the negative connected to ground). Now, take 3 breadboard wires of different colors (I used green, yellow, and blue) and attach them as follows:

Blue connects from Port 11 on the Arduino to the third pin down the right side of the shift register.

Green connects from Port 8 on the Arduino to the fifth pin down the right side of the shift register.

Yellow connects from Port 12 on the Arduino to the sixth pin down the right side of the shift register.

Once all of these are attached, you can begin to attach your LEDs. Take 8 wires of a different color (white, in my example) and connect them to Pins 1-7 on the left side of the shift register. The eighth wire should be connected to the second pin down on the right side. Each of these will connect to an LED.

Take each of the eight wires and connect them to different rows on a separate breadboard. Then, before adding the LEDs, add another wire linking to the third breadboard. Finally, add the resistors to EACH wire, and attach the LEDs to the breadboards, remembering to connect them all to a negative port as well.

Finally, add the test program from the Arduino website (link above), and all the LEDs should light up. If they don't, the LEDs may be burned out- troubleshoot.

Step 3: Measure and Label

First, you have to measure the length of your belt around the wearer's waist. Mark this off with a piece of tape or something similar. Divide this number by 9- once you have that measurement, mark off where those points are. 8 of those points will be for LEDs, and the other for the distance sensor. If possible, give an extra inch or so for the sensor, since it is larger than a set of LEDs.

After measuring these points out and deciding which point will hold the distance sensor (I suggest the point most in front of or most behind the wearer), create two holes in each point vertically across from each other. These holes are where the LEDs will be, so make them large enough to hold the lights, but not too big that they fall out. Mark each of these with a number 1-8 for later purposes.

Once the holes are created, measure out wire from where your Arduino will be held (usually where the belt overlaps itself) to the holes. This will mean that you have eight separate wires with different lengths. Label these to the holes that they correspond to.

Step 4: Create a Circuitboard

Wow, this seems like such a terrifying step, but it really isn't, if you know how to solder. You simply have three "areas"- your shift register area, positive area, and negative area.

The first thing to do is to attach the shift register to the blank circuit board. Again, this is done by bending a few pins and sticking it into the 16 corresponding holes. Besides a few extra sensor wires and some positive/negative connections, this is where all of your wires will be connected. Just like when we tested the shift register, you should connect three colors of wire to their respective ports:

Blue connects to the third pin down the right side of the shift register.

Green connects to the fifth pin down the right side of the shift register.

Yellow connects to the sixth pin down the right side of the shift register.

These wires don't have to be connected to the Arduino yet, but they should be securely attached to the shift register. The way this is done is simple: you stick the wire through the circuit board and solder it to the correct pin. This should be done for all three wires that will be connected to the Arduino.

Next, every wire that must be connected to the LEDs must be soldered onto the circuitboard. Again, these should be attached to Pins 1-7 on the left side and Pin 2 on the right.

Finally, the positive and negative areas must be soldered together. One wire that will eventually connect to the Arduino's 5V port should be soldered to both the positive wire for the shift register and the two positive wires for the distance sensor. One negative wire that will eventually be connected to the Arduino should be soldered to one thick wire for the LEDs and the wire connected to the shift register.

And now you have built your circuitboard,

Step 5: Wire Stripping and Soldering

Now comes the fun part- we get to connect everything together! BEFORE YOU BEGIN, make sure that your LEDs are ALREADY in the holes that you want them in. Otherwise, you will have to completely redo this step, which is a PAIN.
Now, you have eight different wires to power sixteen different LEDs. Clearly, you must Y them off on order to get the correct amount of power to each LED. To do this, strip a tiny amount of rubber off the wire and wrap another piece of wire around the exposed piece. Solder the two together and electrical tape around the area. Do this for all eight wires- remember that the Y does not have to be the entire wire, it can be just the end near the LED.

After each wire has been Y-ed, connect a resistor to the end of each. This is done very similarly- wrap the resistor's end around the end of the wire and solder it. This will be done for each of the now sixteen wires.

Next, connect the LEDs positive end to the resistor. Again, wrap them around each other and solder.

Finally, you must connect the LEDs to a negative wire. You should currently have one negative wire that is slightly longer than the farthest set of LEDs. Similarly to the positive Y-ing, strip off a little bit of rubber in either eight or sixteen places, and solder another wire to connect to the LED. Then, as always, solder the LED to that end of the wire.

Lastly, attach the sensor to the belt (taped on the outside, in this case).

It is very important that you make sure to solder the positive end to the positive wire and the negative end to the negative wire. If this is not done, the belt will not work.

Step 6: Cable Management

By now, you probably have way too many wires snaking around your workspace. Since literally all of this wiring has to stay around your waist, it has to be flattened and neatened. The best way I have found to do this is to simply wrap the wires together so they are condensed and tape them together every few inches, and then tape them to the belt. If wanted, you can flatten the wires around the belt for a more comfortable feel, but somehow, you must control (and hide) the wiring behind a very small strip of fabric.

Step 7: Connecting to the Arduino

After the belt has been wired, it is time to connect the circuitboard to the Arduino so, you know, the thing actually works. This is done simply by connecting the wires from before that are already soldered to the board:

Blue connects from Port 11 on the Arduino to the third pin down the right side of the shift register.

Green connects from Port 8 on the Arduino to the fifth pin down the right side of the shift register.

Yellow connects from Port 12 on the Arduino to the sixth pin down the right side of the shift register.

Finally, your positive cord connects to the 5V port, and the negative cord connects to ground. If you wired everythign correctly, electrical taped all your naked wires, and are very lucky, it should work correctly when plugged in.

Try plugging your Arduino into power, and watch very carefully to see if it turns on. IF IT DOES NOT TURN ON, UNPLUG IT IMMEDIATELY. Something shorted out and it could seriously damage your device. Start troubleshooting- is anything plugged in wrong, are any ends touching, is everything in the right port, etc.

Step 8: Programming

Finally, you must create a code that causes the sensor to make the LEDs light up. I haven't finished this yet, so I can't tell you how it works, because code hates me. :( If anyone knows what to do, feel free to tell me.