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Various Flashlights And Things Get 18650ed, Part 2
#1
I guess we can't post to old threads anymore. Sad
So here's a continuation of: https://secondlifestorage.com/showthread...1#pid11351

Helmet audio project:

When I ride my motorcycle long distances, and have to get to a specific location, I like to use my cell phone's Google Maps app. But I can't hear a thing because of the wind and engine noise.

I also can't afford all that fancy blu-tooth stuff they make for bikers. So I'll make due with various bits of junk and cheep things I've got laying around.


First I got some speakers for the helmet. I don't have pictures of that yet, so I'll skip to the part where I discovered I'd need an amplifier...

Found this tiny amplifier super cheap from China. Some assembly required, but that's part of the fun, yes?
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The directions were surprisingly easy to read.

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Now, I don't know much about amplifiers. But here I'm trying to see how much current it needs. At 12V, it's drawing less than I can measure. Maybe it uses more when there is actual sound going through it? In any case, a 3s1p 18650 battery should be plenty to power it. I tested the device on the full range of such a battery, and it works fine.

I thought about just plugging it into the motorcycle's electrical, but then I'd have yet another cable attaching me to the bike.
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Here it is with the acrylic case that came with it, and some cables I used to try it out. Works great, with very clear sound, and it definitely makes audio signals louder. If the input is too strong, the sound will start to break up at full volume, but it seems to work well with my phone.

See, I have this issue where the phone will default to about 80% volume without my asking, when I need 100%. It's an annoying safety feature. But it works out well, because the volume it keeps defaulting to is about as loud as the amp can handle. So I can have the amp at max volume without the sound breaking up.

I gotta take more pictures, but later I'll post about the helmet and the DIY 18650 battery I made for it.
-Mike G
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#2
Got some pics of the helmet speakers.
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These came from a couple broken GPS units that I bought to repair the one I have that had a cracked screen. The cells and speakers were good in both, so I salvaged them too. Since they're identical, they work well in stereo. I'm no audio expert, but I know that different speakers have different impedance, and if they are mismatched, they won't sound right.

Anyway, the wires all tucked nicely into the back of the helmet, and there was even a little hole that was preformed in the plastic that was perfect for a strain relief zip tie.
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Early on, I had problems with the 1/8" jack coming loose from the helmet. I've replaced it with a 1/4" jack, hoping it will be more solid. Everything is nicely hidden beneath all the removable padding, and just the jack shows.

Also made my own audio cable. One reason is that I had the parts. Another is that I was able to use some old Christmas light wire which is much more robust that your typical audio cable. A third reason is that the connectors are easily repairable if that should be necessary.
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I braided it my self. Looks cool, and also keeps the wires from flopping around.
-Mike G
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#3
So, finally, the battery.

I have a whole box full of these empty Pegatron battery shells which came apart intact enough to reuse.
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I tested several of the original circuit boards, and they were all bad. With a little modification, a generic 3s BMS board will fit in the same space.
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I made sure the amplifier and the battery had the same connector sizes, so all I had to do was build a short patch cable to connect them.
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I haven't had it on the road yet, but it's all working so far. I'll have to get some Google map directions going at some point, since being able to hear that is the whole point of the project.
[Image: b69ea5cdbc448836b84065d37e2b1af6.jpg]
For now, I can hear that having the phone on it's default volume, and the amplifier on full, gives nice sound and is significantly louder than if the phone were hooked up directly at full volume.

Looking forward to a real world test. Smile
Korishan likes this post
-Mike G
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#4
This one won't count towards being second life cells, since they're new. But I thought I'd share anyway.


I bought six 20A cells. Five to rebuild a battery for a drill I picked up at a thrift store, and one to replace the NiCd cells in my electric screwdriver. I posted about that one a while back, replacing old NiCds with new NiCds, but I was still not happy with the way they would self discharge in between uses.

Anyway, I don't know if this will be interesting or not, but here it is.
-Mike G
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