see the previous posts Beyond the Phone - eLIST progress 3 eLIST progress 2 , eLIST progress , eLIST - KOBO Touch , 5W Load Schematic
When I entered the Beyond the Phone challenge, I was also interested in using it for EL lighting.
I had a particular idea, that I would use it for, however it was reliant on a third party being able to obtain the item in question.
They aren't easy to get, and the ownership remains with the distributor, so you can't just go an buy one.
The item has an illuminated circle, which currently uses a lamp of some description, and in theory could be replaced.
For my idea I figured I would use EL Film, as I had seen it previously and thought it would work nicely.
I ordered this white panel and an inverter and waited for their arrival.
I was disappointed with the inverter and the output voltage, which was only 85v instead of the 110v it should be.
However the current draw was much higher than I imagined, and was too high to be practical.
Since the wireless receiver was only 5v, it would need boosting .... time for another solution.
I ordered one of these battery powered inverter that used 2x AA batteries from my local supplier.
https://nicegear.co.nz/electronics-gear/el-inverter-battery-pack/
There were other options, however this looked to have a lower height inverter, compared to the other offerings, which might be important in the final item.
It worked okay but it was still less than bright enough driving the panel.
At this point my intended item hadn't arrived, so I couldn't cut the panel down from it's 100 x 100mm size just in case I got it wrong.
Hence it could have been better with a smaller load.
Using a bench supply, I checked at 3v and the current draw was 400mA.
There was a comment it could run from lipo at 4.2v, so I increased the voltage, and it got brighter along with a corresponding increase in the current.
Finally the magic smoke escaped from the little transistor and it was all over.
(for this who don't know, electronics runs on 'smoke and mirrors', and when you let the smoke out it stops working.)
picture of smd transistor
It was repairable, and a quick call to the supplier would tell me what the marking was on a good one, however the results were less than I expected.
So my foray into EL film as a source of lighting ended in disappointment.
Not because I destroyed an inverter, but mainly because the existing off the shelf items are not that efficient.
I need to do some measurements of the load current, but looking at the number of components and crude transformer used, I think there is room for improvement.
It will work, and can work, but not if you want efficiency as well.
Since I'd spent too much time with the other part, and it was rather late I decided to change tact and go with something else.
see the next part of the story.
Mark