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Month: March 2009

Random Bike Things

Published March 6, 2009

Here’s some random bike things which you may or may not care about…

· After a bunch of shifting problems while riding during the really warm day a few weeks ago I determined that my shifting cables and houses needed to be replaced. Tonight I replaced them, finding the cables intact but the ends of the housings rusty and the innards dirty. I’d had the parts since before I went on vacation, but finally got around to it today.

Cutting the cable was very easy with Dremel cut-off discs and a razor blade and awl for cleanup. I then dripped some Triflow in each end of the cable, fitted the end caps, then assembled everything Shifting is now as smooth as it was when my bike was new a year ago. I’m sure there’s a bit of fine tuning I’ll have to do as the cables stretch, but things seem nice so far.

· I washed my Specialzed bike tonight so that I could replace the shift cable, and at the same time also washed the Bianchi Single Speed. It didn’t really need it, but most bike washing time is spent setting up the hose. So, why not?

· The forecast tomorrow is for highs near 60°F, so I’m hoping to get out for a ride tomorrow after work. I’ll start towards Metro Beach with the intention of riding there and back, but I’m not sure I’ll be able to do the full 46 miles. We’ll see. This will be my first longer distance ride since last fall.

· I’m not so sure about the On-One Mary Bar that I’ve been borrowing. The Bianchi handles very nicely with it on the bike, having a nice twitchy feel that I can’t wait to try on single track, but on longer rides (as Bob and I did last night up through River Bends and back) the slightly odd positioning makes my wrists hurt. Maybe some Ergon grips would help. I do like these, and would probably want them on the riser bar the bike came with, so a purchase wouldn’t be lost money.

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End Panel Mockups

Published March 5, 2009

Cardboard mocked up front panel with the v1.0 / Prototype PCB in the enclosure. Production panel will be 1.5mm thicker.

Tonight after a profanely busy day at work I did cardboard mockups of my current SDrive NUXX front and rear panel artwork. I’m mostly happy with it, but as my printer seems to stretch things out slightly on the page I have to double-check a few things (toggle switch hole and DIP switch markings, in particular), but I think that what I have is close to the final artwork design.

Here is an image showing the rear panel with SIO connector, reset button, etc. Note that the ugly blue switch caps were used because I don’t like them, so I was willing to throw them away on a prototype. The other switch caps may be seen here. I think I’ll be putting black on the front panel and red on the reset button on the rear. It’d be nice if a dark gray cap was available, but Digi-Key nor Mouser seem to list one.

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SDrive NUXX Is Working!

Published March 3, 2009

The SDrive NUXX up and running, with the SDrive by C.P.U. software running on the television behind via my Atari 800XL.

Today I learned a little lesson about programming AVRs†. After sorting that out I was able to properly use the SDrive NUXX‘s onboard programmer with no problem. After that I thought it should have been working, but the device wouldn’t work. Poking around I found the AVR running, but then found that the SD card slot was only getting about 1V, which is far below the 3.3V it requires.

This problem turned out to be caused by the LE33CZ 3.3V LDOs that I’d ordered from Digi-Key. As can be seen here, when fed 5V the LDOs were putting out just over 1V whose datasheets I had read wrong. I stupidly missed the “from bottom” note on the pinout section and been both fitting and testing the part backwards. (This is another thing to fix in the v1.1 / production run.)

For testing last night I worked around this by feeding the SD card 3.3V from a benchtop supply, everything worked great. The following morning I understood my mistake and fitted the parts properly, and now the benchtop supply is no longer needed. The 2GB SD card I’d picked up for cheap at Micro Center worked great, and I had no problems loading most of the .ATR images which I’d tried.

There’s still a couple problems with the PCB, but I’ll sort those out before the production order. Most notably there is the missing traces in the programmer, then I also screwed up the switch marking silkscreen for the front panel. Whoops!

At least it’s working. Yay!

Continue readingSDrive NUXX Is Working!
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Electronics Woes

Published March 2, 2009

Completed board, connected via a M-M DB25 cable to a PC, for programming.

After returning home from a really great vacation Sunday morning (more on that later) and sleeping, I got to work on the SDrive NUXX PCBs which had arrived last week. While the boards themselves look good and went together well, I’ve yet to get things working right. I first had some problems getting the chip programmed, but patching two missing traces (my fault) and powering the target device sorted that out.

Tonight I found that as soon as I set the fuses on the AVR, even after a successful program, the chip can no longer be accessed by the programmer. I believe this is because the programmer is then trying to talk to the chip at too high of a rate, but I’m not completely sure. Also, the option for setting the programmer to the slower mode (using PonyProg2000) is seeming to not work, so I’m not completely sure what’s happening.

Now it’s time to just relax and get ready for tomorrow. That’s another day of work, then maybe some bike riding. After that I can get back to working on this, and hopefully figure it out.

More photos are available on pages 2 and 3 of the SDrive NUXX album.

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