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Category: electronics

iPod Battery Replaced

Published February 24, 2012

Roughly six years after buying my black fifth generation iPod I finally replaced the battery. After years of working well it was starting to fail, providing me with only a few hours of music listening while at work, way down from the original 10-15 that I was getting when it was new.

The replacement battery was part number BIPOD550MV30 from OWC, a very reliable online Apple reseller who has been around for years, and cost just over $20 shipped. While I could have purchased a cheaper battery via eBayI wanted to be sure to get one from a reliable place, so if I had problems with it there wouldn’t be an issue returning it.

The battery is now installed and charging, so hopefully by morning it’ll be full and ready to go.

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Burroughs Mainframe Cards

Published February 17, 2012

Years ago I got the chance to help empty out a friend’s neighbor’s basement after they passed away. This basement was stuffed with old computers and electronics, and I acquired a number of interesting items from there, many of which are now displayed around the house. (Core memory, old test equipment, notebooks, etc.)

The photos from this excursion can be found here, if you’re interested.

One of the items I’d acquired was a milk crate full of old cards from a Burroughs mainframe. Each is a bunch of discrete components built into what’s essentially a logical unit, designed to perform some function. These days a small integrated circuit would be used to perform the same (or multiple) functions.

I’ve given many of these items away, as in my excitement I ended up with many more items than needed. Everything from large boxes of valves to old, uncalibrated oscilloscopes have found homes with friends who had a better use for them than I did. A little while back I was contacted by a guy named William Donzelli who was interested in the history of the Burroughs mainframe and the cards from it. I didn’t know much about it and couldn’t answer many questions, so a couple days back I sent off this box containing the cards to him. Hopefully he’ll find them enlightening.

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Mukluk Fork Light: First Draft

Published December 31, 2011

As mentioned a month ago I had the parts laying around the house for fitting a Philips commuter bike light to a rigid fork crown. I’ve poked with this on and off over the last month, including taking some time to cut a water bottle to hold the battery and fill/fashion the top of it with leftover GREAT STUFF foam. Tonight I finally put together the power supply, built the wiring harness, mounted a bottle cage to a fork, and put it all together.

This looks like it’ll be a pretty good auxiliary light for winter riding; something to provide some nice, low-angle light to increase contrast / shadows. It’s listed as being ~100 lumens, and being a European commuter-style light it’s designed to cast a rotated D-shaped light, illuminating only the pavement and not shining in other riders’ eyes. Being mounted just above the Mukluk’s large tire this casts a decent-sized shadow, but I don’t think that this’ll be a problem when riding. I’m now just looking forward to the trails freezing so I can get out and try this.

To put this together I used the following items, all of which were sitting around the house unused, generally left over from other projects:

· Philips SafeRide BF60L60BALX1 Light
· Tenergy 14.8V 3Ah LiPo Battery Pack
· Sure Electronics PT-PC021 Step-down Power Supply
· Cannondale Water Bottle
· Random Fasteners
· King Cage Bottle Cage
· Silicone-insulated Stranded Wire
· Cable Ties
· Hot-Melt Glue
· Neoprene Sheet
· Left-over GREAT STUFF (Yes, I was somehow able to save a can and get it dispensing again by removing the nozzle…)

I’m not sure that I’ll stick with the fork mount for the battery, but wanting to keep the main bottle cage empty it seems to be the best option. I also might modify the battery holder to be a bit more solid, but right now I’ve got the power supply wrapped in neoprene which nicely holds the battery in place. This results in nothing rattling around and everything working pretty well, so we’ll see where it goes…

UPDATE: Runtime tests show a little over six hours runtime off of one charge. The setup has also been proving quite durable and reliable. I may switch to a smaller battery and a more permanent mount, but for now this setup seems to be working wonderfully.

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Future Snow Bike Light?

Published November 30, 2011

This evening while straightening up the basement I decided to play around with combining parts from two previous projects (a commuter light picked up at the MMBA Expo and the Bicycle Video Recorder) and it seems to work. I’m able to use the rather large LiPo battery and voltage regulator to get the requisite 6V, and it seems to power the light nicely.

The light should be mountable on the crown of the Mukluk, so maybe I’ll put this to work as a low-mount night riding light for winter use. I’ll just have to sort out the battery mount, but that shouldn’t be a big deal. Yay, another project!

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AMB χ1: Complete

Published November 19, 2011

Yesterday evening I finished up retrofitting my AMB Mini³ headphone amplifier with the AMB χ1. This is a battery management board which replaces the original charging circuitry and 9VDC NiMH battery resulting in a considerably faster charge and longer runtime. By using a Lithium-ion polymer (LiPo) battery the runtime has been extended to ~25 hours (for my high performance version) while the charging time has been reduced to ~1.5 hours. (AMB.org claims that this is a 10x improvement in charge time and a 3x improvement in run time.)

The photo above shows the rear end of the Mini³ without the end panel, showing the two LiPo packs (the silver / strapping tape pieces) the edge of the χ1 PCB (top), and the bi-color charge/fault indicator LED. Assembling this involved removing a small handful of diodes, regulators, and resistors from the Mini³’s PCB, adding a header in place of the LM7812 voltage regulator, and plugging the χ1 into that. As documented on AMB’s site building the χ1 was pretty straightforward and involved only a handful of medium-size (and easy to solder) surface mount parts. I almost wish the design was all surface mount so I wouldn’t have to deal with as much through hole, but I understand his desire to not go all-SMT in order to keep things easy to assemble.

I use this headphone almost every day at work while listening to music from my iPod, and thus far it’s sounded great. However, due to my weird patterns of not being in the office I haven’t been leaving it plugged in for long enough lately, so whenever I’ve been wanting to use it I must plug it in to use it. Hopefully this new version with a shorter charge time and longer run time will sort out that problem.

Now I want to build something else, but I’m not really sure what. I’m somewhat considering a beefy Class A amp and new monitor speakers for my desk at home, all nicely integrated with a USB DAC and tucked under my desk. I could even build the monitors themselves, but this would end up being a pretty big project and I’m not sure it’d get me enough benefit…

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Shower Beer

Published October 15, 2011

Here’s to one of the greatest pleasures in the world: a quality beer while showering. I guess this is the evening corollary to drinking morning coffee in the shower, another one of life’s great pleasures. Not only does one get to enjoy a comfortable, relaxing shower a tasty beverage comes along for the trip.

The beer shown here is Big Sky Brewing Company’s Moose Drool, brought to me by my parents from their recent trip out west; seen poured into a glass here. Also in this sampler is Scape Goat Pale Ale, Big Sky IPA, and Trout Slayer Wheat Ale. All of these beers were quite good, and if I can find this stuff in Michigan (I think it’s distributed here…) I’ll likely pick some up.

This shower comes at the end of a long, and slightly frustrating, day. Today was Massive Fallout, a lengthy group bike ride around a number of local trails and an event that I’d looked forward to all year. This morning the weather was rather poor, and being not-quite-properly dressed for it and somewhat uninterested in riding in cold and rainy weather I skipped out on the ride. I don’t regret my choice, but I can’t help but be disappointed at the weather which kept the event from being what I’d hoped. Oh well, maybe I’ll be able to do the ride next weekend with friends or something like that.

(For what it’s worth, this photo was taken with the Olympus Stylus 850 SW that I’ve had for more than three years and which has accompanied me on almost every sweaty bike ride that I’ve taken, a couple of international trips, a few swimming adventures, and random other hostile places and it’s held up great. I’d highly recommend a camera from this series if one is looking to purchase a decent-image-quality pocket camera that can be taken along on almost all trips.)

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Garmin Edge 500 Distance Aliasing Issues Alleviated By GSC 10 Sensor

Published August 28, 2011

Past experience with wildly varying data has prevented me from trusting GPS-based devices for accurately logging distances while riding mountain bike trails, but after hearing reassuring reports of modern units and seeing how useful it could be to have one unit logging data for all three of my bikes and automatically aggregating it I decided to give it a go. I purchased a Garmin Edge 500 cycling computer and a GSC 10 wheel speed / pedaling cadence sensor a month ago and after beginning to use it things seemed quite accurate, but I continued to be a bit suspicious that it may not be providing as accurate of data as it could. So, I decided to do some tests.

The results of these tests have shown that when the Edge 500 is used in conjunction with the GSC 10 it is just as accurate as a wheel-based computer and can be relied on to provide sufficiently accurate distance measurements while riding curvy mountain bike trails. Coupled with all the extra data that the system can log (heart rate, location, temperature, cadence, etc) it’s quite a nice system for recording data.

Without the GSC 10 (using only GPS-based data recording) the Edge 500 showed drastic undermeasurement, 20.70% on a typical Southeast Michigan trail ride and 33.87% in a worst-case test scenario.

Continue readingGarmin Edge 500 Distance Aliasing Issues Alleviated By GSC 10 Sensor
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Black & Decker Pivot Driver (Model 9078) Power Supply

Published August 2, 2011

Today’s public service announcement is to inform you that the Black & Decker Pivot Driver (Model 9078) uses a 5VAC ~200mA power supply with a typical 2.5mm barrel connector for charging. The 3.6VDC marking on the driver itself is the power requirements for the motor, the charging connector is unlabeled, and a decal on the unit simply directs that only power supply 90500898 be used. Now you know that 905 That is all.

(This sort of information is often terribly hard to find when needed, such as when the device needs a charge, the power supply is missing, and a suitable replacement can’t be found. Hopefully stuff like this will one day help someone.)

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SDrive NUXXs Ready To Ship

Published August 1, 2011

There we go, twenty nine (29) assembled SDrive NUXXs packed in bubble wrap and ready to ship. The thirtieth unit is waiting on some parts (small plastic key caps)that Digi-Key mis-shipped. Or, if a buyer so chooses, I’ll fit their unit with yellow key caps. Here is the USPS Priority Mail packaging sent complimentary upon request. It, of course, requires that I use them for all shipping, but I was planning that anyway.

Now, time to sleep. I’m very overtired. This is a bit more work than I planned on.

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