Category: making things

Purple Foam Block

Published March 21, 2010

After getting the battery and power supply going the next step in the bicycle video recorder project was to fit everything in the case. The foam block seen above, carved out of a $2 remnant from The Foam Factory, is a big part of this, as it supports the recorder, battery, and power supply inside the bag. Everything is now assembled, and I’ve even gone for a quick test ride around the courtyard, as seen in this video.

Photos of today’s work begin with the blocks of foam here and end on page 6.

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Battery + Power Supply: Go

Published March 20, 2010

Today I received the voltage regulators to be used in the aforementioned power supply for the Bicycle Video Recorder that I’m working on. They fit perfectly in the PCB that I’d made, and worked exactly as expected. As the battery had a slight charge when received from All-Battery.com I was able to use it to test out the assembled power supply — as seen above — and I’m getting a proper 5V and 12V out of it. This is good.

Tomorrow I’ll give the battery a full charge, as I want to do the first charge in a relatively safe area, just in case something bad happens. I’m also hoping to finish up the routing and assembly of cables that will hold it all together. After this is done the setup should be ready to record video, and I should then be able to take it for a test ride and get on with battery life tests.

Figuring out where to run all the wires (out which sides of what) and how to bundle it all up in the bag will be a bit of a challenge. I’ve got an assortment of foam to use for padding things, but I’m not yet sure how I’ll arrange it all. The SanDisk V-Mate needs open access on the top during use, and the battery has to remain easily removable / unpluggable after use.

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Power Supply for Bicycle Video Camera

Published March 6, 2010

I’ve been working on a video camera system for my bike. The project is just getting started, but today I made the PCB for the power supply. You can see it above fit inside of its project box (a RadioShack 3x2x1″), or you can see the bottom side with solder and traces here.

It’s been a few years since I last etched a PCB, and as I’d run out of photoresist developer (a lye solution) I decided to make due with what I had readily available and laid out the board by hand, drawing it in pencil and marker and using nail polish as resist. I’m quite happy with how it came out. The many-year-expired tin plating chemicals that I had sitting around the basement even worked, giving it a nice tarnish-resistant silver finish.

This PCB and housing is designed to hold two eBay special step-down DC to DC switching regulators (buck converters) to get 5 VDC and 12 VDC from a 14.8 V 3000mAh LiPo battery pack. The 5V will power a SanDisk V-Mate solid state video recorder and the 12V a VioSport Action Cam 3. All of this together with an 8GB microSD card should allow for the continuous filming of eight to nine hours of mobile video while fitting in a small bento-style bicycle bag.

Now to wait for the rest of the parts to arrive so I can put it all together. The camera and recorder are here, I’m just waiting on the ~~hand grenade~~ battery and charger, bento bag, regulators, and powerpole connectors. Hopefully this won’t be too bad for a ~$200 project. The video quality should be decent as shown by this intentionally shaky test which features Danielle and Roxie (warning: contains dog nose) and single-charge recording length should be long enough to capture any bike ride that I might choose to record. More photos are available here, if you’re interested.

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The Last SDrive NUXX

Published February 4, 2010

With this shipment the very last SDrive NUXX is sold, and the project is complete. The bare PCB on top is the first / prototype device with retrofitted ZIF socket. I may use it for future development work, or I might just keep it around as a memento.

Now, time to find another project.

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Rotor Truing Test

Published January 25, 2010

After acquiring a hub (from a trashed wheel that I was given) and borrowing a dial indicator I decided to test out a prototype of the disc brake rotor truing stand that I’ve been wanting to make. Initially I’d planned on making a wood base to hold a hub and either a feeler gauge or dial indicator, but after trying this all out in my bench vise, I’m quite happy with this setup.

I’ve ordered this dial indicator from Grizzly Industrial, Inc., which is the same one seen in the picture above. Next I’ll probably make a plastic or wooden block to fit in the jaws of the vise and hold the bottom of the quick release, and then future truing activities will use a setup just like this.

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IS1621N on BCK-08 PCB

Published January 19, 2010

In other cheap Chinese device news here’s DealExtreme p/n 8422 with the case removed, powered by a benchtop supply, peered to my Nexus One, and playing audio. I’m hoping to redo the output circuitry on this and put it in another case to make a decent Bluetooth audio device for connecting to either a home or car stereo. It runs off of 3.7 VDC and has an on-PCB antenna, so it should be pretty easy to work with.

The PCB contains an I.S.S.C. IS1621N and FM24C08B EEPROM, which likely contains the IS1621N’s config. I’ve requested the data sheet for the chip from I.S.S.C., so hopefully I’ll have that soon and can work on it. I’d also like to change the identifier string in the EEPROM, but I probably won’t touch that until I know what the IS1621N expects to find in other parts of it. I also hope to find an example implementation, as it should be easy to build off of that to get line level output.

Here’s a few more pictures of the board:

· Detail of the FM24C08B EEPROM which likely houses the config for the IS1621N on the BCK-08.
· Top / button side of the BCK-08 PCB.
· Bottom / component side of the BCK-08 PCB showing the I.S.S.C. IS1621N Bluetooth IC and FM24C08B EEPROM.

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Popcorn!

Published January 18, 2010

I am currently eating the popcorn pictured above, which was popped in in a pot on the stove, in a bit of veggie oil. It was then tossed with Penzy’s Brady Street Cheese Sprinkle and a bit of freshly ground chipotle. Yes, real chipotle, first cut up with scissors, then broken down in a blade mill, and finally finished in a mortar and pestle with a bit of salt.

I have also been strongly advised to substitute bacon grease for the veggie oil in the next batch. This seems like wise advise.

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Removing LEDs from a Sony CDX-GT43IPW

Published January 10, 2010

Having some time this evening I opened up the ultra-bright LED-bearing faceplate from Danielle’s new car stereo. I was originally hoping to replace the LEDs with red or green ones, but after seeing that some are part of the tactile switches I decided against that. Looking into things by plugging the bare PCB into the head unit (photo) I found that the most offensive LEDs were those under the horizontal translucent buttons, with two of them lighting each button, and the ring around the chromed selector dial.

The decision was made to remove one LED from under each of the translucent buttons and one from around the ring. The LED removal went well, save for discovering that the ring LEDs are wired in series, so removing one turned off the entire ring. Still, the final result is much nicer. The stereo now lights up blue, but it’s no longer a glaring blue which makes seeing the road at night difficult. If you compare this photo from last night to this one from tonight you can see how much more reserved (and appropriate) the illumination now is. The loss of the knob ring illumination isn’t really a concern, as it’s the only knob on the device so it’s easy to find and other light glinting off the chrome finish makes it easy to see anyway. The tradeoff for less irritating light is worth it.

Interestingly there were two discreet sets of solder pads for each LED, and some silkscreen on the back that indicated selections for amber and green LEDs. I suspect that other similar models of this stereo offered the other illumination colors and this particular model was just for Target, or perhaps low end markets, or something like that. Or maybe this board is just fitted differently when used in other higher-end models…

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Bonding Cut Bicycle Cables

Published December 30, 2009

After installing a bicycle cable and crimping on an end cap, removing it usually results in a frayed cable which is difficult to remove and reinstall. For maintenance reasons I want to be able to do this, so I’ve begun looking at methods to seal the end of a cut bicycle cable as is done with factory cuts.

My first experiments with cyanoacrylate glue (aka Super Glue) seem to work well, and when Erik suggested that I solder them, I decided to give that a go. Some research online indicated that a silver-bearing solder works well, so after acquiring some plumbing solder (with silver in it) I gave that a try, and it wouldn’t wet the surface nor wick into my test cable. Normal lead/tin solder for electrical work didn’t work either. I next tried a blowtorch, and while fun it only resulted in ablating the wire resulting in what is seen on the right.

So, right now I think that wetting the ends of the cable with cyanoacrylate glue is the best solution. This is what is shown on the left, and it results in a rigid, solid piece of cable. Disappointingly the cable could be crushed (and promptly frayed) when squeezed with locking the pliers that I use to pretension cables, but this should be acceptable.

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UHMW Tape Applied

Published December 29, 2009

Today I did a bit more work on my new bike, applying UHMW polyethylene tape to various places where cables are observed rubbing the frame. Thus far it seems to have worked pretty well, although I have to place one or two more pieces to deal with cable rub on the fork. I also spent some time today wrapping the chainstay in an old scrubbed-clean tube tube to protect it from (and silence it during) chainslap. Photos of all of this can be seen under the following links:

· UHMW tape on the left front of the down tube to protect against cable rub.
· UHMW tape on the seat tube to (hopefully) keep the front derailleur housing from damaging the finish.
· A thin strip of UHMW tape on the Fox Float RP23 shock just in case the cable hits here.
· UHMW tape behind the computer wire-wrapped brake line on the fork crown.
· The drive side chainstay has been wrapped with part of an old tube to both protect it from damage and cut down on chainslap noise.

Now that the bike is almost complete (only waiting on a new saddle and stem) I’m becoming anxious to ride it. It’s too bad proper outdoor riding on it won’t happen until spring, when I can be reasonably sure that a bike won’t be stuffed with saltwater after riding around the block. Until then I’ll just keep riding my current bike.

(No, there are no complete photos of the new bike yet… I’m waiting until it’s wholly fitted out with the proper parts before this happens.)

Also, I scanned the piece of UHMW tape seen above along with its mate and the seat tube / rear derailleur cable piece before applying them so that I could reproduce them easily in the future if needed. These scans, at 1200dpi with false color to aid in cutting, can be found here:
Down Tube / Front Triangle Template · Seat Tube / Front Derailleur Housing Template.

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