Touch Circuit Fairy Lights

45-60 min

Intermediate

Ages 8+

What Will You Learn?​

Follow this guide to build a working touch circuit, that turns on and stays on when you touch two of the wires, using your body as a conductor, and then shuts off when you touch the other wire!

This touch circuit is great to build as a working device, and then add it on to a wearable or invention that you create!

Video Overview

In this video, James shows us how to hack Fairy Wire into a touch-activated circuit. It shows you how to add an electronics circuit to a headpiece which can be adapted to other projects easily.

Building the Circuit

STEP 1

Time to create the circuit! It’s helpful if you draw out the circuit on a piece of paper, that way you will be able to build it at your own speed and reference the layout for each step. Take a blank piece of paper, and copy the drawing for yourself.

STEP 2

Get your Fairy Wire out, see how it will match the drawing? You could tape it down in place over the drawing if you like, to help keep track of things. Start with the battery holder. For the wires, we don’t know which one is positive (+) and which is negative (-).

How should we find out? There are several ways. I encourage you to experiment!

STEP 3

One way to find out which wire is positive (+) and which is negative (-) I used a battery! If you hold the battery between the two wires and the lights turn on, then the positive (+) wire is the one touching the positive side of the battery – you can tell because the battery has a plus (+) sign on the positive side!

STEP 4

However! The wires of the Fairy Wire look bare, but are coated with a thin layer of clear plastic. You need to remove this before the battery you hold can turn on the Fairy Wire lights!

Sand the wires for 10 seconds or so, making sure to get both sides. That will remove the plastic, expose the metal, and allow you to test which wire is positive and which is negative by pressing the exposed wires against the battery!

If the lights do not turn on, then flip the battery around so the wires touch the other sides of the battery. If they do not turn on either way, do a bit more sanding on those wires!

STEP 5

Here is the Fairy Wire being turned on with the battery! (my Fairy Wire LEDs are red) Now I know which wire is positive!

STEP 5

Now that you know which wire is positive, you can put it onto your circuit drawing! I’m going to mark my wire with a piece of blue tape and a + mark, to help me keep track. Mark your wire in some way as well. Tape is great, or you could make a little circle loop in the positive wire to tell it apart from the negative.

STEP 6

Next step! *Cut* the negative wire using scissors. Make sure it’s not the positive wire!

STEP 7

You could tape your wires down in place on your drawing, if you would like to keep track. One of the wires goes up to the MOSFET, the black thing with three legs, it goes at the top!

Make sure the back of the MOSFET lays flush and flat against the paper, so that when I say “the left leg”, we are talking about the same leg! To put it another way, the MOSFET has a piece of grey metal with a hole in it, make sure that piece is resting against your paper when you place the MOSFET down on your drawing.

STEP 8

You could tape your wires down in place on your drawing, if you would like to keep track. One of the wires goes up to the MOSFET, the black thing with three legs, it goes at the top!

Make sure the back of the MOSFET lays flush and flat against the paper, so that when I say “the left leg”, we are talking about the same leg! To put it another way, the MOSFET has a piece of grey metal with a hole in it, make sure that piece is resting against your paper when you place the MOSFET down on your drawing.

STEP 9

Connect the next pin and socket wire to the middle leg of the MOSFET! And then set it all back in place. You can see on my drawing the wires are a bit longer than the drawing, that’s okay if yours is too, just as long as you can tell which wire goes where!

One more leg to go!

STEP 10

The right leg attaches to the negative (-) wire! This is not a socket tipped wire, so it is going to require some soldering.

Have you learned how to use a soldering iron? If yes, proceed! If no, have an adult who knows how it is done supervise.

Wrap your negative wire around the MOSFET’s right let. Check everything against the photos, and if it all looks good, it’s time to solder! If you do not solder this connection you *might* be able to twist the wires enough to all hold together. You could try wrapping everything in tape to help, but no guarantees on how well it will hold together!

STEP 11

With the wire wrapped around the right leg, use the soldering iron to heat the wire up for about 5 seconds. Then insert your solder right inbetween the iron and the leg, and melt a big glob onto it! It should take about 2 or 3 seconds to do this. Do not keep the soldering iron held down for more than 10 more seconds, or you might burn the MOSFET.

If you did not get it the first time, feel free to try again after letting it cool down for about 10 seconds!

It does not need to be pretty, it just needs to hold! When you think you have it, let it cool off for about 30 seconds before touching it and then make sure it is melted down.

STEP 12

The last connection! When you have finished this, the circuit should work! Take the other negative wire that you had cut earlier, and take the wire coming out of the middle of the MOSFET.

Twist them together and solder them! Use the same method as before, and make sure you are either trained in soldering iron safety or have an adult supervising.

STEP 13

After you finish soldering this last wire, it is nice to cover the solder with tape to help prevent it from breaking apart or touching any other wires.

This is it! You have constructed a touch circuit!

STEP 14

Time to use the circuit! If you have a piece of tape covering the positive (+) wire where you sanded it down, take it off because you will need to touch that part!

See the wire coming out of the left leg of the MOSFET? Hold that wire, the tip of it, and don’t let go!

With your other hand, touch the positive wire where you sanded it, and the circuit should turn on! Change to touching the right leg of the MOSFET to turn the circuit off.

What’s going on? Your body is acting as a wire, and the MOSFET is acting like an on and off switch.

A MOSFET is like a switch that a computer can control, only the computer has no hands so it must turn things on and off differently than a human. A computer can send positive or negative signals, and it can “sense” them as well. That wire coming out of the left leg of the MOSFET? That is where the MOSFET is waiting to sense a positive or negative signal.

The signal actually comes from your body when you touch either the positive or negative side of the circuit. So, you are speaking the language of electronics when you do that! And the Fairy Lights will turn on and off at your command!

Troubleshooting

If your circuit is not working as expected, time to investigate! First spend some time checking everything against the instructions. Then, have a look around where you are and “read” the situation. Would it be appropriate to ask a friend for help? This is a great way of getting help if you have someone nearby and it’s okay to chat.

How about calling someone on your phone or computer? Would that be okay? Decide the best way to get help based on where you are and how you read your situation.

Some common issues that people run into include:

  • Making sure your Fairy Light switch is on, and that it has batteries in it’s case.

  • Squeezing all the spots where different wires connect to each other. Maybe the connection is not strong enough and this is a good way to test it.

  • Making sure the positive wire is sanded down where you are touching it.

  • Making sure you are holding the metal tip of the sensing wire (the wire on the MOSFET’s left leg) when you touch either the positive or negative wires on your circuit.

How Can This Circuit Be Used?

Fire Nation Hat

Mr. James added the touch circuit to a hat! When he wears the hat, the wire on the *left* leg of the MOSFET presses against his skin on his forehead. This is the *sensing* wire that is waiting for a positive or negative signal. Then Mr. James touches either the left or right side of the hat, where the positive and negative wires are glued down, and the hat turns off or on!

Dragon Cloak

This touch circuit has also made appearances on the MakeFashion Edu runway! Check out this dragon cloak made in Tucson, Arizona. The designer extended all the wires to different spots on her body. She holds a wire pendant at her heart, and then with her other hand touches either her shoulder or elbow.

When touching her shoulder, the gesture looks like a hug and her lights turn off because she is showing friendship. When she touches her elbow, the gesture is like arms crossed in anger. The lights come on and you have to watch out, because she is activating her dragon powers!

Touch Circuit Fairy Lights

Touch Circuit Fairy Lights

45-60 min

Intermediate

Ages 8+

What Will You Learn?​

Follow this guide to build a working touch circuit, that turns on and stays on when you touch two of the wires, using your body as a conductor, and then shuts off when you touch the other wire!

This touch circuit is great to build as a working device, and then add it on to a wearable or invention that you create!

Video Overview

In this video, James shows us how to hack Fairy Wire into a touch-activated circuit. It shows you how to add an electronics circuit to a headpiece which can be adapted to other projects easily.

Building the Circuit

STEP 1

Time to create the circuit! It’s helpful if you draw out the circuit on a piece of paper, that way you will be able to build it at your own speed and reference the layout for each step. Take a blank piece of paper, and copy the drawing for yourself.

STEP 2

Get your Fairy Wire out, see how it will match the drawing? You could tape it down in place over the drawing if you like, to help keep track of things. Start with the battery holder. For the wires, we don’t know which one is positive (+) and which is negative (-).

How should we find out? There are several ways. I encourage you to experiment!

STEP 3

One way to find out which wire is positive (+) and which is negative (-) I used a battery! If you hold the battery between the two wires and the lights turn on, then the positive (+) wire is the one touching the positive side of the battery – you can tell because the battery has a plus (+) sign on the positive side!

STEP 4

However! The wires of the Fairy Wire look bare, but are coated with a thin layer of clear plastic. You need to remove this before the battery you hold can turn on the Fairy Wire lights!

Sand the wires for 10 seconds or so, making sure to get both sides. That will remove the plastic, expose the metal, and allow you to test which wire is positive and which is negative by pressing the exposed wires against the battery!

If the lights do not turn on, then flip the battery around so the wires touch the other sides of the battery. If they do not turn on either way, do a bit more sanding on those wires!

STEP 5

Here is the Fairy Wire being turned on with the battery! (my Fairy Wire LEDs are red) Now I know which wire is positive!

STEP 5

Now that you know which wire is positive, you can put it onto your circuit drawing! I’m going to mark my wire with a piece of blue tape and a + mark, to help me keep track. Mark your wire in some way as well. Tape is great, or you could make a little circle loop in the positive wire to tell it apart from the negative.

STEP 6

Next step! *Cut* the negative wire using scissors. Make sure it’s not the positive wire!

STEP 7

You could tape your wires down in place on your drawing, if you would like to keep track. One of the wires goes up to the MOSFET, the black thing with three legs, it goes at the top!

Make sure the back of the MOSFET lays flush and flat against the paper, so that when I say “the left leg”, we are talking about the same leg! To put it another way, the MOSFET has a piece of grey metal with a hole in it, make sure that piece is resting against your paper when you place the MOSFET down on your drawing.

STEP 8

You could tape your wires down in place on your drawing, if you would like to keep track. One of the wires goes up to the MOSFET, the black thing with three legs, it goes at the top!

Make sure the back of the MOSFET lays flush and flat against the paper, so that when I say “the left leg”, we are talking about the same leg! To put it another way, the MOSFET has a piece of grey metal with a hole in it, make sure that piece is resting against your paper when you place the MOSFET down on your drawing.

STEP 9

Connect the next pin and socket wire to the middle leg of the MOSFET! And then set it all back in place. You can see on my drawing the wires are a bit longer than the drawing, that’s okay if yours is too, just as long as you can tell which wire goes where!

One more leg to go!

STEP 10

The right leg attaches to the negative (-) wire! This is not a socket tipped wire, so it is going to require some soldering.

Have you learned how to use a soldering iron? If yes, proceed! If no, have an adult who knows how it is done supervise.

Wrap your negative wire around the MOSFET’s right let. Check everything against the photos, and if it all looks good, it’s time to solder! If you do not solder this connection you *might* be able to twist the wires enough to all hold together. You could try wrapping everything in tape to help, but no guarantees on how well it will hold together!

STEP 11

With the wire wrapped around the right leg, use the soldering iron to heat the wire up for about 5 seconds. Then insert your solder right inbetween the iron and the leg, and melt a big glob onto it! It should take about 2 or 3 seconds to do this. Do not keep the soldering iron held down for more than 10 more seconds, or you might burn the MOSFET.

If you did not get it the first time, feel free to try again after letting it cool down for about 10 seconds!

It does not need to be pretty, it just needs to hold! When you think you have it, let it cool off for about 30 seconds before touching it and then make sure it is melted down.

STEP 12

The last connection! When you have finished this, the circuit should work! Take the other negative wire that you had cut earlier, and take the wire coming out of the middle of the MOSFET.

Twist them together and solder them! Use the same method as before, and make sure you are either trained in soldering iron safety or have an adult supervising.

STEP 13

After you finish soldering this last wire, it is nice to cover the solder with tape to help prevent it from breaking apart or touching any other wires.

This is it! You have constructed a touch circuit!

STEP 14

Time to use the circuit! If you have a piece of tape covering the positive (+) wire where you sanded it down, take it off because you will need to touch that part!

See the wire coming out of the left leg of the MOSFET? Hold that wire, the tip of it, and don’t let go!

With your other hand, touch the positive wire where you sanded it, and the circuit should turn on! Change to touching the right leg of the MOSFET to turn the circuit off.

What’s going on? Your body is acting as a wire, and the MOSFET is acting like an on and off switch.

A MOSFET is like a switch that a computer can control, only the computer has no hands so it must turn things on and off differently than a human. A computer can send positive or negative signals, and it can “sense” them as well. That wire coming out of the left leg of the MOSFET? That is where the MOSFET is waiting to sense a positive or negative signal.

The signal actually comes from your body when you touch either the positive or negative side of the circuit. So, you are speaking the language of electronics when you do that! And the Fairy Lights will turn on and off at your command!

Troubleshooting

If your circuit is not working as expected, time to investigate! First spend some time checking everything against the instructions. Then, have a look around where you are and “read” the situation. Would it be appropriate to ask a friend for help? This is a great way of getting help if you have someone nearby and it’s okay to chat.

How about calling someone on your phone or computer? Would that be okay? Decide the best way to get help based on where you are and how you read your situation.

Some common issues that people run into include:

  • Making sure your Fairy Light switch is on, and that it has batteries in it’s case.

  • Squeezing all the spots where different wires connect to each other. Maybe the connection is not strong enough and this is a good way to test it.

  • Making sure the positive wire is sanded down where you are touching it.

  • Making sure you are holding the metal tip of the sensing wire (the wire on the MOSFET’s left leg) when you touch either the positive or negative wires on your circuit.

How Can This Circuit Be Used?

Fire Nation Hat

Mr. James added the touch circuit to a hat! When he wears the hat, the wire on the *left* leg of the MOSFET presses against his skin on his forehead. This is the *sensing* wire that is waiting for a positive or negative signal. Then Mr. James touches either the left or right side of the hat, where the positive and negative wires are glued down, and the hat turns off or on!

Dragon Cloak

This touch circuit has also made appearances on the MakeFashion Edu runway! Check out this dragon cloak made in Tucson, Arizona. The designer extended all the wires to different spots on her body. She holds a wire pendant at her heart, and then with her other hand touches either her shoulder or elbow.

When touching her shoulder, the gesture looks like a hug and her lights turn off because she is showing friendship. When she touches her elbow, the gesture is like arms crossed in anger. The lights come on and you have to watch out, because she is activating her dragon powers!

Please Note

Your safety is your own responsibility, including proper use of equipment and safety gear, and determining whether you have adequate skill and experience. Power tools, electricity, and other resources used for these projects are dangerous, unless used properly and with adequate precautions, including safety gear and adult supervision. Some illustrative photos do not depict safety precautions or equipment, in order to show the project steps more clearly. Use of the instructions and suggestions found in Maker Camp is at your own risk. Maker Media, Inc., disclaims all responsibility for any resulting damage, injury, or expense.