Lamp Project – hooking modules to LED

For class this week, we needed to focus on connections. It made sense for Mike and I to continue with our lamp project. We had been talking about what medium to use to make the modules conductive through out the whole process and graphite, inks, leaf, and fabric came up. Graphite is highly resistive, so we decided against that, plus we needed something to that would cover a large area easily. Fabric and leafing were the two most accessible, so we tried leafing first and ordered some inks online here.

While we waited for the inks to arrive, we mixed up some of our own with graphite powder and textile pigment. What we discovered was that I hadn’t applied the leafing correctly doh! so there was a thin line that needed to connect the inside panel with the outside panels that we made conductive.
We also realized that the copper leafing was not secure and eventually fell away. This couldn’t be good for consistent readings later on, but decided to go on and try to patch up the modules in order to get a proof of concept ready.

Getting ready to mix graphite powder with textile pigments

Testing a square inch of graphite pigment for resistance with a module thrown in for scale

We mixed 2 level spoonfuls of graphite powder with one even spoonful of pigment. Painted a 1″ square and tested the resistance, putting our multimeter leads on the outer sides of the square. The reading was about 155 ohms.
Going back to the folding party, we finished our model lampshade.

Finished the mini lamp shade form, total of 105 modules.

Stepping away from our modules and pigments, we needed to figure out the range of resistance we needed in order to change the color of our LED. Mike hooked up the LED to a 10K pot and found that 1K was where it peaked. We checked every pot we had, hoping to find 3 1Ks to hook up and play with. We then found a nifty way to change the resistance of the 10K pots we had. All thanks to Eric Rosenthal. Solder a resistor between the power and ground pin straight on the pot!

Mike testing the resistance of our pots

A great way to change the resistance of a pot. Thank you to Eric Rosenthal for showing us the way!

Close-up of 1.5K resistor

Another example of changing resistance

Our pots hooked up to RGB LED and labeled appropriately

Touch up job given to each conductive module with graphite pigment

The crazy range of resistance coming from our collection of conductive modules. All values in Ohms

In conclusion, we could not get any consistency from our modules. We were able to make 1″ square tests from the inks we finally received, but while painting them on, realized this was not going to be our solution either. Not unless we could come up with a way to evenly apply the ink the same every time. Same thickness of coat, same size of area covered and so on. This could be achieved, but by the ways we came up with, we decided that fabric would probably be the next material that would work.
Next week calls for another focus which we can not include in the project.
This project will be continued!!! So pleace check back later, or shoot me an email with any questions.

Check out the test of the inks here

Here are some videos we took of the led changing color with the pots and one that shows the conductive modules working as a connection, even if it’s a faulty one for now.

Potentiometers hooked up to a RGB LED from lara grant on Vimeo.

Testing modules with RGB LED from lara grant on Vimeo.

Testing modules with RGB LED Part 2 from lara grant on Vimeo.