Here’s my Astrolux EC01, which now has an OLED display, RGB, UV, MELD UI, voltage/current/temperature instrumentation, touch sensor for peek mode, and retains the charging feature.
I figured it was time to try out a 21700 light and see how many features I could add, so I got the EC01. In the past with my lights with added displays, the display has to use the space occupied by the charging port, but fortunately the head on this one is just big enough to fit the display right above the switch. This location makes for a much nicer user interface, and let me retain the stock charging hardware.
I started by milling out the space for the display:
And painstakingly squared up the corners with a small chisel shape ground into a hobby knife blade:
Once convinced the display could fit I knew what the electronics would look like, so I started on the driver. With a small amount of reverse engineering I knew what parts could be removed and identified the connections I would need:
From there it was a lot of wiring under the microscope. I had to cut a trace to insert my 10 milliohm current sense resistor in series with the battery, and then added the INA219 power monitor as well as one of the new 7135 regulators in the space left by the original microcontroller:
Then my new microcontroller board went on top, mounted to the surfaces of the two 7135 parts. This board is a small custom breakout board for the PIC18F26K40:
The three other 7135 regulators were added and wired in, as well as a TTP223 capacitive touch sensor for the touch panel above the display:
To allow firmware changes after assembly, I drilled a small hole through the board and broke out the programming connections to a small board also cut from flex PCB stock (photo taken later in the process):
For the R, G, B, and UV LEDs I hand-cut a board from blank flex PCB stock material which fits around the stock XHP50 emitter:
This board is very thin because it’s flex material, so after gluing it down to the stock copper star the overall height is change negligibly:
Time to move on to the display. This is a cheap 64x32 pixel white OLED display with an I2C interface. It requires a few support components which I wired directly to the flex connector:
A strip of copper tape for the touch sensor is added to it, and then I slid that assembly into the pocket and covered it with a window cut from 0.5mm polycarbonate:
The connections get insulated with Kapton and they fold down to fit beside the reflector:
After adding a thermistor to the color LED board and cutting a plastic insulator/spacer to hold up the reflector, here are all the parts ready to be joined up. At this point I also had replaced the wires from the switch board with the same 34AWG wire to save space:
And after lots of wiring here it is, ready for testing and firmware debugging:
For working on the firmware I set it up like this in a stick vise:
The firmware went relatively smoothly since this was so similar to the SDmini. I just needed to add support to indicate charging and to adapt to the different hardware (7135 + FET). Now for the scariest part of any of these builds (which I call THE SQUEEZE):
There wasn’t really any issue fitting it in though, there was a lot of space in the driver cavity. It just required a lot of care to avoid pinching wires. Here’s the view from the top with the LED board installed:
And optics reinstalled:
The color beam patterns are typical of this arrangement, but not too bad:
On-board charging is a new feature for my lights of this type:
And here’s a quick demo video of how the display looks in use:
Thanks for reading!
just an awesome build, 
thank you for sharing. 
