Snapleds Continued

I finished my first snapled array, and they are damn impressive! I was expecting slightly better performance than the superflux, but was blown away. I haven’t come up with a method of comparing the two yet, as I don’t have a light meter. A side by side with the reflect signs outside the house would be nice, but it’s raining cats and dogs right now!

lumileds snapled vs 3mm superflux

Here’s a size comparison of the snapled versus a 3mm superflux led. Both have a body measuring 7.6mm, but the snapled has those huge contacts, and a much heavier internal structure compared to the superflux. The 5mm snapled lens also looks huge compared to the superflux.

Hand soldering the snapled smt style is fairly easy – this connection lifted up on me because I was pressing down on the opposite side. Soldering the rest I just placed the led and then slid the iron in next to the contact without touching it, then fed in the solder, which sucked the contact right onto the pad like it’s supposed to.

The finished product, before washing. Once I decide on a layout I like, I’ll probably have some boards made and will try reflowing these either in a toaster over or on a skillet.

Lumileds Snapled

I don’t have much to say on these, other than I scored a bunch from Future for a seemingly great price.

lumileds snapled

These appear to be HEAVY DUTY leds, destined for the automotive market. They’re discontinued now, as Lumileds is pushing the all mighty rebel for every application under the sun.

Apparently lumileds marketed these leds strictly as automotive indicator grade leds. Their design guide shows a stop light made of six of these leds, spot welded in a 2 x 3 array to heavy solid aluminum buss bars instead of a typical PCB mounting. I won’t be doing any of that, but I did draw up a layout in Eagle and came up with a 2 x 8 array for my mint tin bike light.

This board is etched and waiting to be cleaned and assembled, more pics to follow!

Mint Tin Bike Light Continued

Nothing much new on a technical note. I do have a new pcb layout ready to iron on to some blank copper, should get that done this weekend. I ordered more switchers and LEDs from Future on Wednesday. Originally I was excited, the estimated delivery date was 8/21. However, it has now been pushed to 8/26, oh well!

Here are some new pictures, and some video worth posting in the blog:

2010 Trek 3700

This is my new 2010 Trek 3700 Mountain Bike… I’ve upgraded to alloy pedals and a super tough downhill rim for the rear wheel. I had been buying cheap-o department store bikes, on average two or three per year and trashing them basically riding on streets and trails. So I wanted to upgrade to something that should hold up a bit better.

Same composure, dialed down the flash output and decreased the shutter speed a little.

Video “tour” of the bike with both lights going.

Strobe effects demonstration on some reflective signs near my house. Sorry for the wind noise, a storm is rolling in!

Mint Tin Bike Light

I started this project a little more than a year ago, but shelved it because it wasn’t working right and I didn’t have the correct components. It was a seasonal project that would have little use over the winter, so I sort of forgot about it.

This year I’ve been going on a lot of bike rides with friends, sometimes on public roadways, sometimes after dark. My bike has a nine watt 500 some odd lumen headlight, which makes it easy to see where I’m going, and definitely makes me visible head on. The tail of my bike however still has the stock reflector, plus the little reflector stripes in my shoes, not exactly high visibility. Not wanting to pale in comparison to the headlight, the taillight is a three watt 140 lumen beast powered by three AA rechargeable batteries.

The light is based on a boost converter from National Semiconductor, the LM3410. I’m using the 525kHz SOT-23 version, the LM3410Y. Originally I had trouble with the chip self destructing, as discussed on the Linear1 forums. It was hypothesized either the inductor was underrated or the diode was too slow. Ordering parts for another project later in 2008, I bought some better inductors and diodes, which more closely resembled the specs of parts used in National’s web bench simulator. So, lacking sufficient rear light, I rekindled this project and have a “working prototype” that’s gone on two rides with me so far.

bike taillight schematic small

The basic function is fairly simple. The 3410 is a constant current boost (step-up) driver. A small inductor is used to ramp up the input voltage, from 3.6vdc nominal to 15.4v at approximately 200mA. The current is monitored by a one ohm resistor. A pair of output capacitors help smooth out the ripple and an input capacitor helps the batteries cope with the high demand current (as high as 1.5a in some cases). I’m using nickle metal hydride batteries, which have a rather low internal resistance – they’re designed for high demand applications and when fresh, barely sag at all under the load.

bike taillight pcb layout small

Originally I had planned on carrying the batteries directly on the PCB, using some through-hole spring clip battery holders I found in the Sparkfun library. However, AA batteries must be bigger in Colorado than they are in Michigan, because using Sparkfun’s layout gave me about a quarter inch gap between the spring and the battery. The pads were also woefully undersized for physically mounting the clip and holding it securely enough to survive the stress of batter insertion and extraction. So I dropped their layout and drew my own that looks exactly like it, but is based on measurements from a real AA battery.

Along for the ride is a Microchip PIC microcontroller, the 12F683. It provides a bit of user interface for the light, creating different blink patterns as well as putting the light into a “stand by” mode, with the switcher shut down. I’ve programmed several blinking patterns, and somewhat organized them into “modes” which I can select using the little button.

A year ago, I didn’t have any sort of enclosure in mind. The led array was assembled on a ‘standard’ sized protoboard, so I probably thought about using a plastic or aluminum prototype enclosure. However, this year, I was thinking it would be a nice fit for a large mint tin. After printing out some mock-ups and messing around with battery configurations, I settled on using three batteries and having the electronics crammed into one side of the tin with the led array mounted in the lid of the tin. This setup might have worked, except for the battery snafu. I’m using a plastic three cell holder right now, and the extra thickness it adds is preventing the lid from completely closing. It closes enough that the light is easily held shut by some big rubberbands, and it survived bouncing around under my seat for two short rides. The next revision will have the battery situation resolved and I might have a better mounting solution by then too.

Overall I’m very pleased with the outcome of this project. I have more parts on order to make a few more lights for my other bikes and friends, and I want to experiment with other array configurations and colors. There are a two videos of the light on my youtube channel, but they’re nothing to get excited about.

Thanks for reading!

Roll baby roll

The train has spent the last few hours speeding Eastward, I think we start heading North after Marshall Texas.

Here’s a screen-cap from Streets 2009, click on it for a huge version.

The sleeper car is a little different this time. The tiny closet has been replaced by a large hook and an open storage area. The single large step which you climbed to get into the bunk is now two steps, a little narrower. The halls feel narrower too, i think the room might be a tiny bit larger.

Our conductor is doing a better job keeping this rig rolling. The trip North is progressing more smoothly, we’re spending a lot less time at the stops.

My seat is on the west-facing side of the train again, so I’m seeing the same scenery again in reverse… I don’t really think I’m missing anything on the other side.

My EVDO connection has been working pretty good, I’ve been getting 15-20kb/sec uploading all these pics and videos.

After the Faire

Greetings Everyone…

The Faire is behind us now, and to sum up “how was it?” in one word: disappointing.

The fair reminded me of our local Independence Day festival in Manistee. It’s mostly arts, crafts and performers. The difference is, there were a few nerds in the corner, and fighitng robots.

The Faire had several major areas; the arena area housed some big ass tesla coils, some sort of lame robots with balls competition and the ComBot cage. The tesla coils were cool, but they were mostly just a light show to some midi controlled drums and a really loud PA system. The fighting robots were the coolest thing at the fair. It was very impressive to see the heavy weight and super heavy weight bots go up against each other. The smaller bots just sort of danced around until time ran out.

Next we have the Maker Stage, which was an outdoor tent covering raised platform and rear-projection screen. Different Makers and visionaries had scheduled talks. In general they were hard to hear, and the projection was useless. The tent was open on three sides and kind of small. The screen was washed out, and the PA wasn’t very loud – it had to compete with the human mousetrap and the electric guitar bicycle contraption.

Indoors we had the Maker Shed, selling many of the commerical projects covered on the Make blog. Lots of leds, arduinos and other assorted electronic gizmos. The shed had three tiny areas dedicated to demostrations and hands-on. If you purchased a kit from the shed, you could solder it together there which was nice, especially for the young folks just starting out.

In the rodeo barn there was the craft sellers. A little further down a company selling big CNC mills was cutting various things, and demoing a snap-together kit house they’d developed for temporary housing usage. Further down were some home-made CNC’s cutting away at various designs. Sparkfun had a decent sized booth at the end of the barn, showing off some of their eye-candies and doing soldering tutorials. On Saturday there were a few large LEGO cities setup, which were quite impressive. A few real hackers had their tables grouped together, show casing musical gizmos, nixie tubes and surface-mount soldering. A computer club named Austin Modders had some nice looking rigs on display, but they weren’t really doing anything. Duke University had several different teams displaying their work on parallel computing. I spoke with one of the engineers for about twenty minutes – he was very informative, it looks like a great program to be in.

Outside there were some art-bikes, a stage playing eccentric music, model rocketry, kite building and flying, and last but not least, a small trebuchet. I was lucky enough to stumble upon it right before a launch; it was most impressive.

I’m going through my pictures and videos right now, uploading as best I can with my evdo connection. Right now I think I’m on the sprint network and it seems pretty fast.

find some videos here:
and pictures here:

More to come!

That's Lunch

chicago stuffed deep dish pizza

This pizza was lunch on Wednesday.

Dinner on the train was not so good. They were sold out of most things, I had to settle for some dry and flavorless salmon. Things were too hecktec for any pictures… Will try again today.

The train is about an hour and a half behind schedule – I hope they can make that up, since I don’t really want to be getting into San Antonio at 23:00 or later!

Greetings from the Texas Eagle

According to the trusty GPS, I’m south of Joliet Illinois. The train is rolling at sixty mph right now, and seems to max out around eighty.

The ride is a lot rougher than I thought it would be – so much for “riding on rails” referring to a smooth ride. It’s so bumpy and turbulent I’m having trouble typing. Here’s a picture of my laptop setup in my little room.

Lunch at Giordano’s was excellent. The small pizza was too much for this man to tackle, I had to leave some behind. It was only a five minute walk from the train station, almost right across the street from the Sears Tower. The weather was not at all pleasant, I didn’t take many pictures.

I can’t get my phone to roam on the EVDO network, so I’m stuck at 1x speeds … better than nothing at least!

Trying hard not to judge.

I made this mistake of printing the schedule of stops for my train, the Texas Eagle. I’ve been reviewing the stops, seeing if there’s anything of interest that can be seen from the station. In Saint Louis, the gateway arch is very close – I hope the weather cooperates so I can snap a few photos.

However, I’ve developed the habit of looking at the track mileage between stops, and the time Amtrak claims it takes the train to travel that distance.

So far the worst stops I’ve found are between Dallas and Forth Worth. The train is scheduled to arrive at noon in Dallas, departing twenty minutes later for Forth Worth. The track distance between the two stops is thirty-one miles. However, the train is not scheduled to arrive at Forth Worth until 13:55. So that means Amtrak estimates the train to take roughly an hour and a a half to cover that thirty-one miles. The train then takes a leisurely fifty minute stop in Forth Worth before rumbling south-westerly for Central Texas. Luckily I’m not traveling all the way to Los Angeles on this train. After arriving in San Antonio at 22:25, the train does not depart until 5:40 the next morning!

I continue to remind myself, taking the train is not about getting someplace quickly.

Almost Time!

Wow, it seemed like the vacation was a long ways off, and it still feels that way, but I’m leaving Wednesday.

The train leaves at like 08:15 on Wednesday, so I’ll be leaving my house at about 05:00 so I can get there early and maybe have a quick breakfast. The Giordano’s a few blocks away on Jackson is still my plan for lunch during the ~3 hour layover in Chicago. According to my folks and the Amtrak website, people traveling with a room on the train have access to some sort of lounge with a concierge that will secure your baggage for you.

Once I’m on the train, I want to roll a lot of video of the view out the window. A little googling and I found some ideas for real-time transcoding of DV output from a firewire camera direct to mpeg4 xvid files. This setup will let me film for 100’s of hours using my little 160g portable usb drive. I’ll also shoot some footage of inside the train with my shooter – I imaging it’s pretty tight in there, and I don’t have a fisheye lens.

I got my ticket for the fair in the mail a few days ago – it’s not nearly as fancy as the passes to other technology conventions – just a plain paper ticket with multicolor printing on it, no holograms even!

If anyone going to the fair wants to contact me directly, shoot me a gmail @ gordonthree and I’ll give you my cell phone number. I plan to travel with two phones, one of which I’ve subscribed to EVDO internet service on. Maybe I can even blog during the train ride.