My Solution to adding LED battery indicator LEDs

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99quidam
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My Solution to adding LED battery indicator LEDs

Post by 99quidam » Wed Feb 22, 2017 10:15 pm

I really wanted to have a visual battery indicator on my build and was able to externally wire the LED outputs from the Powerboost1000c to the front of the DMG case. Use this link to see the numbered pictures of what I did, unfortunately I did not photograph throughout so I had to make a few pictures. https://postimg.org/gallery/2dpv55npi/

1 - You'll need three LEDs, I just used some cheapo's from an old flashlight and sadly didn't have different colours so I used Sharpies to colour my clear LEDs which worked okay considering I didn't want to wait for nicer hardware.

2 - Use some Perf board. I clipped away a TINY piece that was 2x6 holes. I recomend doing the cutting of the perf board first in case it breaks off unpredictably, which would suck if you already finished the board. I soldered my 3 LEDs to the small board and soldered 6 very small gauge wires to them (I think ~28-32 gauge although the smaller the better). I then clipped off the dome part of each LED, so the the tops of the LEDs were nice and flat, this is easy to mess up as the actually diode in the LED has a chance of splitting off with the plastic lense portion of the LED (you may want to do this part first too). The separation between the centers of the LEDs is important for drilling the holes in the front of the case, I think mine were about 8mm.

Side Note: I thought that in theory the LEDs should all be able to get grounded to the same ground pad on the powerboost, however when I tried this I fried 3 LEDs, and thankfully did not fry the powerboost. I attribute this mistake to my lack of understanding of the powerboost's wiring schematic. This is the reason I use 6 wires and not 4.

3 - Next you need to desolder the 3 LEDs from the powerboost 1000c, I did not bother using the 'charge complete' LED as it is redundant: the charging LED turns off when the charge is done. Keep track of which side of each LED is ground, I remember each LED having a little green dot indicating ground (green=ground?), I am 90% sure the labels in my photo are correct but you can confirm by illuminating each LED using a multimeter set to 'diode test'. I first tried this modification by just adding my LEDs without removing the surface mount LEDs from the powerboost (a.k.a. in parallel) and it did not work (maybe because they are SO small comparatively). Finally solder each of the 6 wires from the 3 LEDs on your Perf board to the 6 exposed pads where the powerboost LEDs used to be (ground and power to ground and power for each LED respectively).

4 - I used the smallest drill bit I had for my Dremel which was 1.5mm diameter and centered 3 holes in the small groove in the front of the case, with a center to center distance = to that of the LEDs on my Perf board.

5 - Finally I carefully glued the Perf board (after testing of course) in place so the LEDs shone through my case holes. This spot works really well with Wermy's custom parts GBZ build as it leaves a nice open space here for the LEDs.

This is what I ended up with, it works and is a hardware-only solution to having battery power indicators. I am still considering plugging the 3 holes with a translucent glue of some sort to reduce the brightness of the LEDs as they are a bit too bright for dim environments.
*no current limiting resistors are required in this build* (should be obvious but just saying).

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drafterITA
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Re: My Solution to adding LED battery indicator LEDs

Post by drafterITA » Fri Mar 10, 2017 9:01 am

thank you for posting this information! I'd like to implement this feature in my build too, so I'm interested :)
in this reddit post https://www.reddit.com/r/RetroPie/comme ... owerboost/ they say that it's possible to solder cables in the back of the led's resistors.. do you think it's possible? I'd be much more comfortable if I didn't have to desolder them, they are so tiny!! :)

thank you!
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Re: My Solution to adding LED battery indicator LEDs

Post by McGyver » Fri Mar 10, 2017 3:18 pm

Same idea:

I placed low bat and charging LEDs in the rest of a cartridge. I used flat heat leds from ebay:
http://www.ebay.de/itm/140748947687?_tr ... EBIDX%3AIT

Finally another good idea I found somewhere was to put the Raspberry Zero into the cartridge shell to get access to the SD card from outside. Just wire up the external HDMI port was quite difficult to handle due to length and connector size issues but worked at the end.
IMG_20170310_230444.jpg
IMG_20170310_230444.jpg (2.08 MiB) Viewed 2350 times

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