Digital Tinkering – CapacitiveSensor

This week I have been working on concept developments, and even though I have not chosen a concept to develop further I shall exploring the different way’s I can bring those interactive elements to life. The concept ” ” has a element that can be replicated by using a CapacitiveSensor in it’s simplest form to test the amount of capacitance in the body. Capacitance is a measurement of how much electrical charge something can store, and can be used to manipulate LED’s (there are many other components that can be programmed to change in accordance to capacitance in the body).

Project 06

The library checks the two pins on the Arduino, one is a sender, the other a receiver. This measures the amount of time it takes for them to be in equal states. Both pins are connected to a piece of metal (or an object) like tin foil or copper mesh. Your body will absorb some of the charge so when your body moves closer, it increase the amount of time it takes for the two pins equalise.

CapSensor-1
Setting up the components; LED, 220 OHM resistor, 1 MEGOHM resistor and metal foil.

In order for me to upload the code to my board, I had to download Paul Badger’s CapacitiveSensor library. Once I had unzipped the file I was able to save it as a new directory, this allowed the to open and upload the code to my Arduino board.

Screen Shot 2018-02-28 at 12.29.47
Code can be made modified and made more interesting by adding multiple CapacitiveSensors.

These following projects expand upon the basic code show above, it helps to illustrate how quickly this simple code can be used to create some really interesting ideas.

Alan Chatham (2012) project turns a pencil drawing into a CapacitiveSensor for Arduino. This project gives you a lot of flexibility in making interfaces for whatever microcontroller project you’re making.

AlanComponents used; pencil, 220 OHM resistor, paperclips and clear tape.

When touching a conductive object it always creates capacitance.  This increases the ability of the conductive material touched to store a charge. It easy to make cheap capacitive sensor by measuring how long it takes for a piece of conductive material to go from a grounded state to a higher potential state when pulled up to that higher state through a resistor.  The higher the capacitance, the longer it will take the conductive material to be pulled up to the high state. Graphite conducts electricity.  Therefore, if we take our conductive pencil line, pull it to ground, then try and pull it to a higher state, we can measure how long it takes, and if we’re touching the drawing, it will take longer to get to a high state than usual.

This Youtube video demonstrates how he sensor works.

This is an interesting and create way to create micro controllers and is something to investigate further if I choose to develop concept three ‘Co-creating Artefact’ further. One way this technology could be used is by having each of the objects to have capacitive sensor ‘hotspots’ that give the user the ability to change what they see visually, moving the story along.

Kristin Williams project ‘Music Notes’ is a homemade device that allows users to record and replay music on sticky notes. The sticky notes are embedded within the RFID sensors and record the music made by drawing over the copper tape or tapping your fingers on its surface. The music note can then be removed from the pad. Later someone can hear their earlier recording by placing the note back on the Note Pad box.

WilliamsComponents include; 8.5″x11″ surface, styrofoam, copper tape, 220 OHM resistor, alligator clips, RFID sensors, sticky note, particle board, duct tape, glue and paint brush. 

This Youtube video demonstrates how he sensor works.

 Reflection

This mini project has the capacity to be expanded further. In my example the hand affects one LED but on a grander scale I could use multiple LED’s (or other more interesting outputs) and CapacitiveSensor’s to create something that the audience can interact with in interesting ways.

I am finding it difficult to understand the language used and I’m unable to write my own code – this is quite frustrating I was hoping I’d be able to pick it up quicker as I have used it in previous projects. I have decided to start typing the code (instead of coping and pasting), although this is more time consuming I’m hoping it will help me to process and retain the information better.

References

Chatham, A. (2012). Retrieved from http://www.instructables.com/id/Turn-a-pencil-drawing-into-a-capacitive-sensor-for/

Williams, K. (2014). Retrieved from http://www.instructables.com/id/Music-Notes-1/

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