Stickytape Sensors

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About: My work combines conductive materials and craft techniques to develop new styles of building electronics that emphasize materiality and process. I create working prototypes to demonstrate the kinds of electr...

Intro: Stickytape Sensors

Simple Pressure and Bend Sensors made from stickytape, Velostat, conductive thread and small pieces of conductive fabric.

Basically you just have to get the conductive surface and Velostat ratio right. I find the following methods work best. As little conductive thread as necessary to cover the sensitive surface. For up to a two cm wide strip, it can be enough to have a single thread running down the center of the strip and three layers of Velostat in between each thread.

VIDEO
Stick a stickytape bend sensor to your wrist with some extra stickytape!


VIDEO
Make your stickytape bend sensor and hook it up to your computer in less than 4 minutes!


VIDEO
This video shows the full process of making a stickytape bend sensor and hooking it up to your computer in less than 5 minutes.


VIDEO
This video shows the graph of a super slim stickytape bend sensor inside a regular drinking straw.

Step 1: Materials and Tools

The materials used for the sensor are easy to buy online. They are also relatively cheap. I would guess that you could make up to 1,000 sensors for less than 30$
When shipping to north America, I like to order from LessEMF because they stock all three essential items, are quick to ship and the prices are reasonable.

Velostat is the brand name for an anti-static plastic manufactured by 3M. The plastic bags in which sensitive electronic components are packaged are made of this material. It also runs under the names: anti-static, ex-static, carbon based plastic, ESD, Linqstat (made in china), Lagerbeutel (German for storage bags)&
So you can also cut up one of those black plastic component bags if you have one at hand. But caution! Not all of them work!

MATERIALS:
- Any kind of stickytape will work, but it can be nice to use a duct (gaffer) tape for its flexibility and robustness. You will find a wide selection of tapes at your local hardware, office supply store and stationary stores.
- Velostat by 3M from http://www.lessemf.com/plastic.html
- Conductive thread from http://www.lessemf.com/fabric.html
- Conductive fabric from http://www.lessemf.com/fabric.html

TOOLS:
- Knife
- Scissors
- Random objects to handle stickytape

Step 2: Tape

Cut two identical pieces of stickytape the size and shape of the sensor you would like to make. Basically every sensor will be pressure sensitive and if you bend it then you can call it a bend sensor. I tend to make my bend sensors lengthy in shape.

If you like you can download these stencils for guidance. But i really think this Instructable is more fun with less precision and more free-form.

Simple Pressure Sensor >> http://kobakant.at/downloads/stencils/SImplePS.pdf
Simple Bend Sensor >> http://kobakant.at/downloads/stencils/SImpleBS.pdf

NOTE: As in all steps, take a close look at the pictures to better understand my description. Plus, always think about different ways to do things. Maybe you can make these sensors even simpler or possibly improve their performance!

Step 3: Thread

With lots of patience, place a piece of conductive thread on top of the sticky tape so that it covers the area that you want to be sensitive to pressure, but really only put as little as necessary to cover this area. Too much conductive surface will ruin the stability of your sensor. Make sure that one end of the thread is far from the edge and the other extends beyond the edge.
Apply to both sides.

Step 4: Fabric

Cut two small tabs of conductive fabric and place them on top of the protruding end of the conductive thread so that the tab half sticks to the stickytape and half sticks out.
Apply to both sides.

Step 5: Velostat

Cut three pieces of Velostat that are slightly smaller than the shape and size of your sensor. Stick one to either piece of stickytape and then prepare to stick both pieces of stickytape together and include the third piece of Velostat in between. If everything holds together, all is good.

Now you are finished. And can test it with a multimeter. Or see the last step in my Fabric Bend Sensor Instructable for information on how to hook your sensor up to your computer >> https://www.instructables.com/id/Fabric_bend_sensor/

Enjoy.

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40 Discussions

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bobank

7 years ago on Introduction

What is stickytape. I am not from this country and maybe i used it but not under that name. Can that be any tape or some specific and where to buy it.
Thanks

1 reply
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Pluseabobank

Reply 7 years ago on Introduction

you can use any kind of tape that is sticky. scotch tape, gaffa tape....

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Hey, great instructable! I'm planning to build sensors for an interactive staircase and this looks perfect. What was the actual peripheral you used to connect to your laptop? Was that an arduino or just some other serial to usb? Thanks for all the help and congratulations again!

1 reply
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Pluseafburali-forti

Reply 7 years ago on Introduction

yes. an arduino and you can use the internal pull-up resistors as voltage dividers for the sensors!

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InDaClub

8 years ago on Introduction

Hi all,
i just want to know the difference of preassure sensitivity of ESD chip foams like
http://www.esdproduct.com/detail.php?pid=13857&cid=

Actually i want to build a electronic music keyboard which is completely preassure sensitive. I know that it will need a procedure to calibrate the values from sensor to send a precise value to computer. I dont know the actual difference between low density foam and high density foams or velostat. I just want to know which one will give me huge variation of resistance against preassure of the three matrials?

My guss is that high density foam will not give good results as it will be variying its resistance in a narrow band.

4 replies
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PluseaInDaClub

Reply 8 years ago on Introduction

I have not got much experience with the foams, but Velostat has a nice (large) range from 2K - 200 Ohm.

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InDaClubPlusea

Reply 8 years ago on Introduction

Plusea thanks for a quick reply. hearing good experience of yours i just want to know if velostat is returns to 2K value consistently. I am planning to etch a copper clad and make PCB with contacts (like those in LDR etc). then i will plate it with some anti corrision like may be gold plate it, then put a velostat strip over it with metal pieces (completely flat) or should i use steel slightly bent underneth each key so that they act as small spring's(?).

actually i think that velostat wraps arround wire and that is what make it a force sensing resistor, when you release it, it makes less contact and the surface area of contact decreases. I want to be sure to get the maximum variation like my piano has a after touch sensor which is a preassure senesor strip giving values from mega ohms down to 300 ohms and i know its very very expensive to install under each 61 keys. currenly it works for the entire keyboard and give one resistance value for all keys. btw i can design using microcontrollers intelegent circuitry.

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PluseaInDaClub

Reply 8 years ago on Introduction

I'm not sure you can rely on the consistency of the Velostat. It may well change over time under use. Another material to look into would be anti-static rubbers like Zoflex. I would recommend experimenting with the Velostat since it is cheap and easy to use.

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InDaClubPlusea

Reply 8 years ago on Introduction

ZL45.1 is exectly what i need. Thanks.

You know a lot about these things. And very nice article here.

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katsideswide

8 years ago on Step 5

Hi!

Thanks for a good instructable!

I'm a little lost however. I made the sensor as instructed, using the blue "labestat" dissipative film that my arduino came in. I then installed the arduino and processing programs, plugged in my arduino and installed the program on it.

Then I connected one side of the pressure sensor to the analog in 0 pin, and the other to the analog in 1 pin and ran the processor program. It gave me the graph but all 6 inputs were fluctuating up and down like crazy! applying pressure makes no discernible difference, apart from maybe making it fluctuate more. Disconnecting the sensor makes all the bars calm down a little but not completely.

Does this sound like a problem with the sensor or a problem with the arduino to you? I'm a real noob at this! I'm trying to make a small toy that makes a sound when the user picks it up. Capacitance would be best I think but it sounds super tricky...

Anyway. Thanks for a cool instructable!

2 replies
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Pluseakatsideswide

Reply 8 years ago on Step 5

first of all, i'm not sure if the libestat has similar piezoresistive properties to velostat and linqstat and thus might not work to construct the stickytape pressure sensor. to test this separately from the arduino, connect the two sides of the sensor to a multimeter set to measure resistance and see what happens. if you get changes in numbers that look reasonable, then it should also work with your arduino setup.
one mistake i see is that you want to connect one side of the sensor to ground and the other to analog input 0. that is what the code is written for.
another test to do is to simply connect two wires, one to ground and one to analog input 0 and see what happens in the graph. when they are not touching the graph should be still. when you touch the wires together, one or more of the graph bars should swing all the way to the other side and remain stable there.
i hope this helps you. let me know if you have more questions.

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katsideswidePlusea

Reply 8 years ago on Step 5

Hi Plusea,

Thanks very much for your help! I've managed to get a better result now that i've connected the right things together (noob fail...)

The program responds as described when i connect the ground and input 1 together, so i guess it must be my switch. I'll try again with a different anti static! :D

Thanks so much!

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caplinq

8 years ago on Step 1

CAPLINQ offers a Velostat alternative called LINQSTAT and we stock it in both Canada and the Netherlands.  You can see the link here:
http://www.caplinq.com/linqstat-vcf-s-series-linqstat-volume-conductive-film.html

We will soon be offering standard sizes in 2mil, 4mil and 8mil.  Check the site for updates.

Due to popular demand, within a month, we are also going to offer a silver conductive Velcro (Hook & Loop) as well and anti-static fabric.

Contact us for status.

Antistatic Non-PSA LINQRO.JPGAntistatic Polyester-Cotton.jpg
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VALKIR

8 years ago on Introduction

 hey, I really enjoyed looking through your sensor instructables and also the youtube vids (oh and i really liked the "sencitive glove" ) but I dont know if i can find the materials you used. i read above that you can use wire instead of the thread (which reduces bendy-ness) but the other things i'm missing are the conductive fabric - you used some copper mesh ... can aluminum foil be used as well? like thicker, i have some of that ,not the thin food packing one? and also- the Velostat , what common household material can I use instead? it needs to be non-conductive,right? will a strip of electrical tape work ? or is that velostat semi-conductive under certain conditions (like bending)?

2 replies
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VALKIRVALKIR

Reply 8 years ago on Introduction

 oh, now that I've done some reading about the velostat  - isnt it used for shielding electronics and stuff? if so- cant I just use the "static" bag from my motherboard? i'm starting to feel like can't be closer to the truth without missing the point completely ... lol

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PluseaVALKIR

Reply 8 years ago on Introduction

yes you can totally use wire and aluminium foil (the regular kitchen stuff will work fine) or even copper tape. and the velostat is anti-static packaging material but only the black anti-static bags work, and then not all of them. do you just have to check. this is also a great non-fabric instruction:
http://www.imagesco.com/articles/flex/sensor-pg1.html