BARE Conductive Paint

Initial report by Manuela Donoso 30 03, 2012 (not finish)

Introduction

Bare Conductive Paint is electrically conductive. Is a non-toxic carbon-based conductor paint. Acts as a conduit for electrical signals to run across a variety of surfaces. It can be applied with a brush, stamp, or spray and can be used to power small devices such as LED’s.

Sources

They sell the paint in Amount: 50 ml and in pens

Sparkfun: Costs: $24.95 + shipping
Thinkgeek: Cost: $29.99 + shipping (economy $5.49)
Inventable: Cost: $ 29.99 + shipping
Bare Conductive: Cost: £18.00 (free shipping worldwide, US 10 working days)

Applications

It can be used in signaling and powering. Signaling could include using the Paint as a potentiometer while interfacing with a micro-controller, as a conduit in a larger circuit or as a capacitive sensor. Powering a device would include lighting LED's or driving small speakers, among other things.
Here are some ways in how can be used as a sensor:

Capacitive Proximity Sensor:

This sensor can detect the presence of a person from up to 300 mm and can work behind any non-conductive material (glass, wood, plastic, etc). The circuit contains a resistor (among 100k ohm and 20M ohm) between pin 2 (orange wire connecting to the breadboard) and pin 4 (red wire connecting to the breadboard) of the Arduino board. Pin 4 is referred to as the "Sensor Pin" and Pin 2 is referred to as the "Receive Pin". Then connect it to the pad of Paint.
Using different resistor changes the sensitivity. Larger resistors tend to make the sensor more sensitive and as such it will work from farther away.

Here is a complete tutorial of how to make one.

Electrical Characteristics

(Bare Paint is relatively new so they don’t have a data sheet yet)
- Is not conductive until it dries (dries at temperature room).
- It cannot be use with an electrical source exceeding 5v DC.
- Resistance is around 60 ohms/sq (square) at a thickness of approx. 1mm. (In it depends on how you apply the material as shape and layer thickness). A 1mmx1mm square has the same resistance as a 10mmx10mm square…of the same thickness.
- After the ink is dry the material can last years if treated properly and kept dry.

Pin Descriptions

Give a list of the pins, and a pin diagram as appropriate. Detail the function of each pin in a short paragraph following the list.

Microcontroller Connections

Explain how to connect the sensor to a microcontroller or computer. Include a schematic and any other necessary diagrams. Make sure to include a list of every part in the schematic.

Additional parts needed to use it

To build sensor with conductive paint, there is lots of parts that can be used, depends on how and what application. It can be applied in wood, paper, glass...
As conector to the paint to controller, can be any conductive material, here some examples:

Code Sample

Capacitive Proximity Sensor: code
For the code of this sensor need to be installed a CapSense library

Give a code sample for the microcontroller you developed the example on. Link it to the Code group of the wiki, formatting the link like this:

[[Code.myCodeSample | Code Sample]]

Typical Behavior

-Let the Paint dry completely before testing it., on a piece of paper should dry within 10 minutes in optimal conditions. dries the conductivity increases (and will continue to increase to a certain extent even after the Paint "feels" dry), so if your project requires calibration.

-Don't use water to diluid the paint, adding water alters the conductivity of the paint.

Describe the behavior of the sensor when you use it to sense something. Note any peculiarities that you had to work around, or things that might affect someone else's use. Graphs and images are useful here.

Application Notes

Describe your own application of the sensor. Link to any external documentation of your project, and discuss how you got the sensor to do what you needed it to.

References/Bibliography

Add links to any reference material you used to learn about your sensor. Cite your sources for explanations, code, and circuits.

Keywords

Conductive paint, Ink, electrically conductive material.