Sunday, October 28, 2012

Printed replacement parts


About 45 minutes start to finish, a little more than it would probably have taken me to find the right part online and order it, but about half a penny of plastic and not having to wait 3 to 5 days for the part to show up.

Friday, October 26, 2012

Test: cheap eBay thumb drives


A few weeks ago I decided that I would like to have some thumb drives that were so cheap that I could just hand them to someone and not worry about getting them back.  To that end, I went to eBay and bought ten 4GB USB thumb drives for $3.85 each from a Chinese vendor
They were listed as 8MB/s write, 10MB/s read.  When they arrived I decided I’d better test them, and it’s a good thing I did.

I used the programs h2testw and chkflsh for testing. This takes a while for full testing.  Results:
2.3MB/s write instead of the claimed 8, and 5 of the 10 thumb drives had persistent data errors, corrupting data that was written to them.
Since I’ve never conducted testing of flash memory before, I decided to check everything I had. I discovered that two of the three PQI 2GB MicroSD cards that I had in my memory card pouch were totally dead, I’m RMAing them. Also I have a “JOGR” 8GB thumb drive which is glacially slow and has a persistent I/O error at a certain spot – I’m just tossing that.  Apart from that, I had no problems. I have a Patriot thumb drive, several 2GB microSDs, an 8, a 16 and two 32GB microSDs and two 16GB SD cards that all test OK.
The eBay vendor says that he’ll refund me for the 5 defective 4GB sticks. We shall see.
I still want a fistful of thumb drives, but I think I’m going to go down to Costco and pick up a 10 pack of Kingston 8GB sticks for $65 rather than “deal” shopping.  Memory devices are too important, and name brand ones are not that much more expensive than cheapos, to take the risk.
My advice is to pick up chkflsh here and use it on new or old flash drives. It can take a couple of hours for a quick test and up to a day for a comprehensive test; a quick test is probably fine.  One thing – if you want to test drives > 4GB, you’ll need to format them NTFS first as it writes one big test file and under FAT32 a single file can’t be bigger than 4GB. You’ll probably want to format it back to FAT32 again before using it since NTFS has some disadvantages when it comes to USB thumb drives.

Saturday, October 20, 2012

eBay “1600 lumen” bike light and aftermarket light lens

This week I bought from eBay a new bike light and also a lens meant to modify the beams from the common type of bike light.  The light itself was an incredible deal at $38 plus about $4 for shipping, shipped from the US and arrived here in just a couple of days (USPS priority).  The lens was $5, and I wish I’d bought one long ago, as you’ll see later on in this post.
Here you see all the junk you get in the package. A charger, a 4 cell (16450 2S2P) battery pack with a sufficient but somewhat flimsy fabric bag, a head band (I think the elastic straps could easily be removed and you could zip-tie this to a helmet for a really good head mount), two O rings and the lighthead itself.

Waterproofness: IMO the lighthead should be waterproof.  The battery, probably OK in light rain conditions, but I wouldn’t want to subject it to a downpour as shipped. Either drop it into a waterproof container or at least slip a plastic bag over it before inserting it in its pouch.
Some people asked about compatibility with MagicShine batteries and cables. Unfortunately the connectors are not compatible with MagicShine due to the differing diameters of the water protection sleeve around the connectors.  The MagicShine shroud is larger so they won’t fit together. Actually I like the one on this light a bit better – it’s still sufficient to repel the water, but the MagicShine is so hard to put together than I have damaged the wires on multiple occasion drying to twist the connectors apart. This is especially hard to do in cold weather. Points to this light on that count.
I think if you were willing to do some surgery you could force them to mate, the actual electrical connector seems to be the right size, but you would then not have a positive snap connection to hold the wires together, they would tend to fall apart while riding and you’d probably have to use tape to hold them together. I wouldn’t recommend it.
It’s listed as being “1600 lumens” but of course there is no standard for how lumens are measured so this isn’t that useful. If you’re not familiar, “lumens” simply means how much light is flowing through a space per second. If you measure it right at the LED it can be a big number but that’s not a useful value – what you want to know is how much useful light is delivered to where you need it.
My old light is an original MagicShine sold as being “900 lumens.” Reliable folks online have measured that model as really being about 450 lumens.  This light is definitely putting out significantly more light, just at a wild guess I’m going to say that it puts out in the range of 900 lumens in that it seems about twice as bright.  Not 1600 but for the money it’s incredible to get 900 lumens.
The pattern is very smooth and very narrow.  There’s no blotchiness.  Almost all of the light goes into a very narrow beam that throws quite a long way, and there’s a halo that is quite wide and much dimmer.  Personally as it ships I don’t think I really like it as an only light since the beam is a bit too concentrated.  I would either want to run it in conjunction with a “floodier” light, but check the lens section below…
 Here’s a video that I shot comparing the beam from this light and the MagicShine:
As you can see, this light is quite spotty.  This may actually be acceptable if your riding conditions are mostly smooth pavement and you just want a long throw for avoiding obstacles at higher speeds.  Again, keep reading to the lens bit below…
Here are some beam shots with the light as shipped.  All shots are MTBR standard ISO 100 f/4 4 second shots.


OK, here it is.  Here’s the lens that I bought for $5 off eBay.
Here’s the beam after this lens was installed:
Honestly, this is really, really good.  So good that I think this light with this lens is, for me, the perfect road light. Tons of light, and while not a full cutoff, it’s as good a shaped beam as you’re likely to be able to easily buy in the US.  With this lens in place I’m happy riding with this light alone.
The only downside to this light is a lack of high durability.  the battery pack is NOT waterproof, and the wiring is not super durable.  It's not going to do well off-road, and people who are rough on their equipment or who must remove their lighting regularly to prevent theft should probably look for something a bit more up-market.
Update: Runtime test on high was about 2.5 hours. I didn’t see when the light on the back went to red, but at 2 hours it was still green.

New printer: JGAurora A3

This week I decided I'd had it with all the other printers in my stable.  The CTC is stable and decent but it just bugs me (can't st...