Mining for milliwatts

March 15, 2019Dan No Comments »

Those who know me well, know that I like to tinker with electronics projects. And tend to have a lot of projects going at any given time. Lately, I’ve been playing with lithium ion batteries.

I’ve always enjoyed playing with batteries, using them to power remote control toys, or small electricity projects when I was a kid. I remember gutting 12v fans from HP desktop computers (386’s I think) and using them on hot summer days to try and stay cool, powered by 12v batteries. I’d use a big external battery pack, jankily wired into my gameboy, to keep it going on long car trips.

Much more recently, I learned about lithium-ion batteries, enjoying both their rechargeable nature and high power density. They keep my hexbright flashlight shining bright and allow it to recharge easily. I have a LiFePO4 battery in my motorcycle, which is one of the few batteries that will fit in its tiny pancake-shaped battery compartment and still have enough power to crank the engine. I also have a bicycle with an electric motor and large lithium ion battery pack – that pack uses 56 little 18650 lithium ion cells. The Tesla motor company famously uses hundreds of them to power their cars.

Back to the pictures above – I’ve had 2 old laptop battery packs kicking around my house for several years (14 years in fact, actually following me through 4 different moves). I’ve been meaning to recycle them, but then I started wondering if there were any useful cells inside of them. Many folks online are harvesting cells like the above from old battery packs they can find, and using them to power bikes or skateboards or even their house. It’s a rather common failure mode for 1 or 2 cells in a laptop battery to go bad, making the pack useless for powering a laptop. But there’s still life in the other cells.

…I was able to remove 15 18650’s from these 2 old packs – could they be any good?

Another broomball season wraps up

February 28, 2019Dan No Comments »

Winter at Michigan Tech means a few things – snow, Winter Carnival, and broomball! Thought I’d highlight that last one a bit here, as I have just wrapped up my 9th season of playing Michigan Tech broomball!

Michigan Tech takes broomball pretty seriously, with hundreds of (mostly) students taking part every season. Stats are kept and bragged about very seriously:

This last season was a good one, in fact my team won all of our games except for 1 – a pretty good record if I do say so myself. I look forward to broomball every year, it’s a nice excuse to be outside and be active, and engage in some friendly competition. I do also look forward to the time it frees up in my schedule, when it’s all done…

As an aside, one thing I look to be doing with this extra time is building out a new website – I’ll just leave that here for now, more coming later!

APRS in 2019 (part 2)

January 31, 2019Dan No Comments »

Well, I mentioned in my last post I was having trouble getting APRS to work, and needed to do some further troubleshooting. As it turns out, the free program direwolf is a pretty neat utility for doing many APRS tasks, including troubleshooting.

I was able to download and install direwolf, tune my alinco radio to 144.390 Mhz, and run an audio patch cord from my alinco radio to the audio-in port on my PC. From there, I was ready to have direwolf decode any APRS messages my radio could receive, and carry on troubleshooting.

Forgive the small text – the above shows the output I was able to get from direwolf, after setting my Anytone radio to operate in GPS beacon mode. Note the top 2 messages, direwolf is able to tell there is a digital message here, but notes that it’s not in the AX.25 format, and can’t cleanly decode it.

On a whim, I changed the aprs path from what I believed to be correct, ” WIDE1-1,WIDE2-2″ to just “WIDE2-2”. And success! Note the bottom 2 messages, which direwolf was able to decode successfully. Apparently my Anytone radio doesn’t operate correctly with a comma in the Path setting (and doesn’t handle that failure gracefully at all. I’m sure you’ll hear more about APRS in the future 🙂