When I went to Montano Velo to buy some spokes and a rim for a new wheel build, they sold me Phil Wood spokes. I bought double butted spokes, so it took a few minutes to prepare them on the spoke machine. I had always used DT spokes and I really didn’t notice that they weren’t DT spokes until I started threading them through the hub and saw “PHIL” embossed on the butted section near the spoke head. I used Damon Rinard’s free spoke length calculator, which is an Excel spreadsheet with macros, to calculate the length of spokes that I needed. After truing and dishing the wheel, the spoke length calculations proved correct.
I also used a Mavic Open Pro rim. The Mavic Open Pro rims have double eyelets, which hopefully distribute the stresses through the two sections of the rim. I considered the Mavic CXP33, which has more of a V-profile than the Open Pro. I guess I’m a traditionalist. I’m not interested in saving weight – I just need strong wheels that will hold up to someone who weighs 13.8571 stone and occasionally bunny hops on craggy Oakland streets. I have never had any problems with Mavic rims. In the past, I have used the G40, GP3, GP4, MA40 and MA3. On my first ride today, the wheel didn’t pretzel so I guess it’s working.
After building a new wheel and acquiring a new 13-26 Campagnolo Record 8 Speed Ultra Drive cassette, I needed to change the cog in the final position from a 26 tooth to something larger so I could have a lower gear for hills. My normal ride has a Category 3 climb, according to the Tour of California’s rating of bike climbs. There is also a short 9.5% grade that I dread every time I get there, so the extra 2.6 gear-inches makes a difference.
I couldn’t find an 8 speed Campagnolo cog larger than a 26 tooth but there seemed to be Miche (Campagnolo 10 speed compatible) cogs with 27, 28 and 29 teeth for sale on eBay. According to every source I found, Campagnolo 10 speed cogs would not work on an 8 speed hub, mainly because the splines are deeper and there is a stepped-ridge on one of the splines. That’s where the Dremel cut-off wheels come in. After a few minutes with the cut-off wheel and some chamfering of the splines with a file, the 10 speed cog was now 8 speed compatible.
There is a CR2032 lithium battery for power, though there is a connection on the circuit board for a power supply. The display could be kept on continuously with a AC/DC power adapter if you wanted to use it as a desk clock (or you could carry around a large battery wired to the watch on your wrist).
The component count is very low – you can see all of them in the photo. The two ICs and the LED module are soldered directly to the board to keep a low profile. The build time for someone familiar with soldering is probably less than an hour. It took me a little longer because I tried to use a yellow LED display module that I ordered from Digi-Key but the digits did not light evenly. The SpikenzieLabs forum suggests that a higher voltage (<5v) might work but I didn’t try it. I unsoldered the yellow module and used the red one.
You should note that this is a big ass watch. A woman’s watch case might be 23-29mm in diameter while a men’s watch case is normally 37-42mm. The Solder : Time case measures ~ 60.8mm (2.4 in). People will notice the Solder : Time on your wrist unless you are the size of Andre the Giant.
I’ve had adafruit.com‘s MintyBoost 3.0 kit and USB LiIon/LiPoly charger (this is v1.1) for a while but I never put them together. I liked the size of the Altoids gum tin of the previous MintyBoost versions I have built but I wanted a little more charging capacity than 2 AA batteries could provide. I wanted a suitable battery and enclosure that didn’t compromise charging capacity and size.
The battery’s capacity: MintyBoost mWh = 3.7V * 2600 mAh = 9620 mWh input
The amount of current it can provide: Output mAh @ 5V = 9620 mWh / 5 * 80% = 1539 mAh output (80% is the conversion efficiency)
Number of iPhone 4S recharges = 1539 mAh / 1430 mAh (iPhone battery capacity) ~ 1.1
The MintyBoost kit requires the soldering of a few components to a circuit board. I also made two mods to the internal battery charger. With this version (1.1) of the adafruit LiIon battery charger, removing the resistor R4 and replacing it with a 1K ohm resistor allows the internal battery to be charged at 1000 mA.
The internal battery charger has connections for external status LEDs. I connected current limiting resistors between the board and LEDs, then mounted the LEDs in holes in the Altoids tin. The green LED indicates that the internal battery is charging and the yellow LED indicates a fully charged battery. (LiIon/LiPoly charging tutorial at Adafruit Learning System)
The battery and circuit boards are mounted in the Altoids tin with double sided foam tape. I made a miscalculation in the height of the LiIon charger taped to battery – the cover won’t close when the charging cable for the internal battery is attached.
To charge the internal battery, a USB Mini B plug supplies the power to the internal battery charger as in the photo above. To charge a device, a USB Standard A connector is used. There’s also enough room in the Altoids tin for storing an Apple 30-pin to USB Cable.
Below are charging test results with an iPhone 4S starting with battery at 49%: