Making, baking, and (un-)breaking things in Southeast Michigan.
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With coming bad weather cancelling this morning’s planned ride at Maybury I instead fixed the GPS that I collected yesterday. This one was crashed and had a broken screen, and due to my recently gaining access to a good screen out of one with a bad mainboard I was able to swap parts around and make a working Edge 305 again.
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I’m working on a Garmin Edge 305 for a friend’s boss which was reported to have a problem finding satellites. After reproducing the problem I opened it up, only to find the body of one of the tactile switches missing and apparently nowhere to be found. This was quite a mystery, as the case had supposedly never been opened before.
After opening and closing the case the not-finding-satellites problem appeared remedied (likely by the full power cycle), but I was confused by the apparently missing button. Rob’s boss had reported that the missing button had been “acting up”, but with all these parts missing the button simply wouldn’t have worked. With the underside of the battery the only place the pieces could have possibly gone I popped out the battery only to find all three pieces stuck in the adhesive which normally holds the battery to the chassis. While they are the size of (large) grains of rice I was able to get the switch reassembled and functioning. Unfortunately, the not-finding-satellites problem is back.
This means that the owner had to have crashed hard enough to blow apart a tactile switch through the rubber housing, bounced it around enough to get all the pieces under the battery, then squished (squeezed?) it all back together. I suspect that in the process a (quite inaccessible) solder connection on the GPS module broke, the metal bits bouncing around the case shorted something out, or something else in the case broke leading to the issue of satellites not being found. It’s too bad I can’t fix that part.
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Today I fixed another Garmin Edge 305, although it’s still a bit strange. This one wouldn’t find any satellites, so I pulled it open to look for broken solder joints and after nothing seemed awry I tried it again and it worked fine. I suspect that it just needed some manner of hard power cycle to get it working again.
What’s also strange is that the down arrow button isn’t working, apparently due to the top and plunger of the tactile switch not being there. When I opened the device they weren’t there and I really can’t tell where they went, as the unit appeared sealed. I can’t help but think that it was dropped, the switch broke, and something happened which caused the GPS to need a hard power cycle. Despite this I couldn’t find the switch parts in the case, either by removing the PCB or tapping/shaking it to dislodge things under the glued in battery.
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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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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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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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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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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:
23 Comments· 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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I guess this is what I get for buying discount ZIF sockets on eBay: one “genuine” TFXTDOL-brand DIP28 ZIF socket. It’ll probably be fine, even though I had to fight with pins which are too wide for sockets and almost too wide for the drill holes in one of the SDrive NUXX prototype boards.
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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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