Walter just got his USBtinyISP kit, built it and shot a video of him demonstrating a how to program a chip with a simple blinking-LED program.

There’s a lot more to read at his site so be sure to go there!

Mike adapted some green spokepov kits to make a first revision of a 3d LED bonsai tree! Read his blog to see details on how he made all three versions of this project including neat pics and videos.

Amazon’s S3 (Simple Storage Service) isn’t new, but its certainly gaining traction. Its a wonderful product for people who have a lot of content on their site (images, video, downloads, pdfs) but not a lot of money. Data storage costs $0.15 per GB-Month (prorated), and $0.20 per GB. No minimums, rounded up to the nearest cent.

There are a lot of great providers out there (I use Laughing Squid and highly recommend it) but even LS’s ‘largest’ package is too small for ladyada.net… What to do? Easy: Host all that bulky content at S3, then use mod_rewrite to reroute it over to S3. (You could also do it with php, asp or similar for higher ’security’ but mod_rewrite is lighter and good enough for me)

For example, this image has the url reference “http://www.ladyada.net/images/mintyboost/assemblyv12/inductorusbplace_t.jpg” but if you access that url in your browser, it is automatically rewritten by apache to http://s3.amazonaws.com/ladyadanet_mintyboost/assemblyv12/inductorusbplace_t.jpg

(same with my research pdf, a big pdf that easily accounted for 500M a day of traffic at its peak! http://www.ladyada.net/media/common/thesis.pdf -> http://s3.amazonaws.com/ladyadanet_common/thesis.pdf , S3 doesn’t care what the data is or how its encoded)

Of course mod_rewrite is not necessary, you can always just directly reference s3.amazonaws.com but that makes it harder to move the content around if you decide to eventually go with another service (or if s3 goes away one day!)

OK so, what’s the point and what does this have to do with electronics, eh? Well one of the killer apps of open source and public domain electronics is documentation. That means media. And media storage, backup and transfer is extremely expensive for the everyday person. It becomes increasingly difficult to host a project when one digg-storm or slashdotting makes that ‘free’ webpage account go down.

Edit: I use the Firefox S3 plugin to upload and set the access control on my files.

Are you using S3 or something similar for your projects, kits or documentation? Leave a comment or email! Its always interesting to see what other people are doing in this space.

I’ve updated the Wave Bubble schems and board files to RC1a which fixes the 2 or 3 bugs notified to me. Check the d0x out from the download page

People on the ladyada.net forums have all sorts of projects they work on. Mike Witt wanted to measure capacitance but his meter doesn’t have a C measurement mode.
However, he remembered that in 555 timers, the frequency is dependent on capacitance so he whipped up this super-simple capacitance meter. Initially I suggested going with the AC waveform method but this is probably just as good and much easier. Just vary R1 and R2 to get different frequency ranges for measurements

(I forgot to add values, R2 and R1 are both 1k ohm
Q is the output, that’s what I hook to my scope.

C_HI is the high end of the cap (if you want to test a polarized cap)
C_LO is the low end. –these don’t matter on standard ceramic caps

Vcc should be between 5-9v, but can be up to 15v safely. 5v is a good TTL level.
To find out C, use the equation C=t/R (from t=RC)
Since my scope only gives frequency, I substitute t=1/freq
We know R (R=r1+r2), so we get
C=t/2000
In my test case, I get freq=2.25676kHz
that means that freq=2256.76Hz
So…
C=(1/2256.76)/2000
~0.00044/2000
~.00000022155 F
~.22 uF

The Cap I used was labeled 224J, which makes it a .22uF +/-10%

Many multi-meters have frequency counting too

Read more about it on the forums

Ziemaginations designed a Mintyboost-derived USB charger except he used a different chip. The MAX1675 is more efficient (up to 95%!) and can also provide more current for those high-powered devices

I jammed Santa’s GPS so he couldn’t find his way to your house.

“In a high-population-density city, inhabitants must be prepared to defend their own personal space. Technologies that increase personal productivity are on the rise, even though they may intrude on others. The unavoidable reaction is to create technologies that counteract other people’s devices. Wave Bubble is a product that counters the all-too-familiar annoyance of loud ring tones and overt cell-phone conversations in public.“

Part of the “Social Defense Mechanisms” projects designed for my MEng thesis.

Wave Bubble was developed under support by EYEBEAM during my R&D fellowship at the Open Lab, thanks!

Sometimes its really important to have a stereo system for your bike. SCUL has a ’standard’ method by which they use a 12V SLA hooked up to a car stereo which is then wired to some car speakers. It’s cheap and easy but I’m never one to leave well enough alone. Thus my ultra-light/ultra-efficient pimped-out bike stereo system:

• 2 x 7.4V 4Ah Lithium Ion Camcorder batteries = 15V at 4A = 60W of power! ($20 each)
• Class D amp. I use the TPA3001D1 you can get kits for this, I made my own PCBs cause I wanted to make at least 4 amps. Either is A-OK. up to 20W output! Is TSSOP so a pain to solder.
• Cheap MP3 player (this one was ~$10, uses MMC cards and a AAA battery) You dont want to get your iPod all dusty. Requires an MMC card, a 256M is like $25 or something.
• Speaker(s)! I recommend old car speakers. Making an enclosure for them will make them sound better but they’re sort of engineered for poor enclosure design. Cheap/thin cookpots work great and come with an attachment point even!

(more…)

OK so boards came in, and there’s 80-100 to be assembled. They’re pretty simple boards: 1 8-pin micro, 3 resistors, 1 capacitor and 2 4-pin header plugs. Since it takes a long time to solder, I designed the board for mass-manufacture: surface mount parts!

Eventually everyone needs to make a lot of PCBs (at home), the best way to do this is to use solder paste and a reflow oven. Since EYEBEAM has a laser cutter I can use it to make a screening stencil and a registration frame. (You can also buy stencils from your 4pcb.com and probably a bunch of other PCB manufacturers) Then it’s super fast to make tons of PCBs. Just silkscreen on solder paste (available at digikey), place the components, and bake!

***

(more…)

Last weekend I found an hour or two to relayout the PCBs to fit into the square tubing better. The boards are thinner and theres a tab below the microcontroller so you can grab it with a pair of pliers without damage.

There’s also a white silkscreen square to write an address to identify each PCB (since they’re addressable)

Then I checked the gerbers with GC Prevue and sent them off to 4PCB.com tuesday afternoon. With 2 day turn and overnight shipping that means they arrive Friday. Since it’s Kate’s first order with them, she gets $500 off the order… Basically we pay for shipping ($50).
Tomorrow I have to solder up 80 Duel Nature PCBs (maybe try out making silkscreens on the lasercutter)