# how to distribute voltage locally on a surface?

#### JJoll

Jul 7, 2013
11
hi,
this might be a little bit confusing that is why I have uploaded a picture with this post.
I do have a 2inch by 2inch square sheet of sample that has been divided to 9 equal sections. I have to apply different surface voltages to each sections every second, how can I do this in the most efficeint way? my initial though was to use one of those conductive films for each section (put conductive sheet on top of each section the connect wires to conductive sheet) then connect each section to a wire but in this case 9 wire will be sticking out of the sample which is undesireable for this project. is there any transparent conductive film that can delivare different voltage to different sections of itself (different area on itself)?
thanks

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#### BobK

Jan 5, 2010
7,682
Even if there was, then how could it change from one pattern to the next?

I think you are stuck with 9 different voltage sources.

Bob

#### shumifan50

Jan 16, 2014
579
A bit more info would help. Can there be wiring on the back of the panel? If so, you could supply one voltage and use resistors to drop the voltage between panels(depending on current requirements). Thta means you would only need 2 wires into the panel. each sqare can be supplied from the back through a hole to the voltage surface.

#### Laplace

Apr 4, 2010
1,252
First option is to create an SMD PCB and attach it to the back of the 2x2 sample. On the PCB will be 9 DAC, or 1 DAC multiplexed to 9 lines directly connected to each of the sample squares from behind.

Second option is to use 9 fine wires connected directly to each of the squares. Then twist the 9 wires tightly together so it appears as one wire. Cover the wires with heat shrink plastic tubing if necessary. Or use fine gauge ribbon cable to give the appearance of 1 wire instead of 9.

#### Gryd3

Jun 25, 2014
4,098
You can use a product like http://en.wikipedia.org/wiki/Indium_tin_oxide to make transparrent traces on glass...

There are other products as well.
http://en.wikipedia.org/wiki/Transparent_conducting_film

You need to account for the resistance of this film, and you will still most likely need 9 wires off the surface. You can be creative and use thin magnet wire if your project allows and route the wire along the edge of the surface. You can also dictate where those wires will connect if you can make your own traces on the surface you are making, which should help them remain hidden.

If you could fill us in on what kind of surface you are using, we can offer more advice.

#### JJoll

Jul 7, 2013
11
A bit more info would help. Can there be wiring on the back of the panel? If so, you could supply one voltage and use resistors to drop the voltage between panels(depending on current requirements). Thta means you would only need 2 wires into the panel. each sqare can be supplied from the back through a hole to the voltage surface.
You can use a product like http://en.wikipedia.org/wiki/Indium_tin_oxide to make transparrent traces on glass...

There are other products as well.
http://en.wikipedia.org/wiki/Transparent_conducting_film

You need to account for the resistance of this film, and you will still most likely need 9 wires off the surface. You can be creative and use thin magnet wire if your project allows and route the wire along the edge of the surface. You can also dictate where those wires will connect if you can make your own traces on the surface you are making, which should help them remain hidden.

If you could fill us in on what kind of surface you are using, we can offer more advice.

I am working on one kind of material that changes its colour (RGB) as you apply a voltage difference on both side of their surface. so for example if the voltage difference between back and front surface is 5 volt the material will turn green and if it is 3.5 volt it will turn red. now I want to put very small size of these material next to each other and create a picture as these pieces act like pixels of that picture. That is why I need a TRANSPARENT conductive material to apply this voltage difference and that is why I dont want to connect one wire to each pixel becuase imagine it is a 100 X 100 picture then there are 100 wires sticking out the picture. I kinda like the idea of using two main wire to apply the max volt then using a potenntameter to control the voltage applied. I personally was thinking about a kind of matrix kinda structure that does the thing.

#### Gryd3

Jun 25, 2014
4,098
I am working on one kind of material that changes its colour (RGB) as you apply a voltage difference on both side of their surface. so for example if the voltage difference between back and front surface is 5 volt the material will turn green and if it is 3.5 volt it will turn red. now I want to put very small size of these material next to each other and create a picture as these pieces act like pixels of that picture. That is why I need a TRANSPARENT conductive material to apply this voltage difference and that is why I dont want to connect one wire to each pixel becuase imagine it is a 100 X 100 picture then there are 100 wires sticking out the picture. I kinda like the idea of using two main wire to apply the max volt then using a potenntameter to control the voltage applied. I personally was thinking about a kind of matrix kinda structure that does the thing.
Is this material transparent or matte?
If this material is matte that you are using, you could hide the conductors behind the surface and provide a common to the front with a transparent conductor, or conductor on the perimeter

#### BobK

Jan 5, 2010
7,682
100 x 100 is nothing. The display you are looking at right now probably has on the order of 1000 wires coming out on each of two perpendicular sides.

Bob

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