Hack saturday – spend $25 free on amex @ small business

American express has a one a year campaign where they will reimburse you $25 if you register your amex card online and spend more than 25 at a participating small business. Just to reiterate, here are the two rules
1) register your (amex) card online at http://shopsmall.com
2) buy a minimum of $25 worth of stuff from an amex approved small business. Want to find one? Check out their online small business finder.

Just so you know that this isn’t “too good to believe” you can see that I did it last year and got a bunch of free gear from sparkfun.

So here is why this is hacky enough to go up on my blog. The small businesses don’t have to be local to you. They just need to be on the map. I’ve looked for a bunch of my favorite small open source hardware / reprap stores and have a small list. The most difficult part is that you need to know the store’s physical address, and their name according to amex. I’m sure that I have missed some just because they might have their cc account under a different name than their actual store name.

Here’s my list:
pololu
makerbot
inventables
artisans asylumn
matterhackers
protoparadigm
robotshop
hobby fever
DIY Drones (3d robotics)
you do it electronics

NOT eligible – post with the zip code and address if you can find that they are actually there. I would LOVE that.
shapeways
sparkfun :(
ponoko
adafruit
emsl
printrbot

It’s not too late to register, and I haven’t picked out my list yet. PLEASE post your thoughts for any hacker friendly small businesses that accept amex, or even better – check them out on the map and post back here

mini free-day @ sparkfun?

The other day I saw a tweet from sparkle labs saying that they were ‘participating’ in American Express small business saturday. The jist of that event is that Amex will give you a $25 statement credit if you register your card on their sbs site and then use it to buy more than $25 from a small business on November 26th.

I did a little sleuthing and it seems like Sparkfun also qualifies. They show up on the sbs page in a search for Boulder, CO. There is no sure-fire way of knowing if it will work, but all signs point to yes.
If you want to give it a shot, be sure to actually register your card on their site, buy some stuff, and have (spark)fun supporting small businesses!

Please note: This has nothing to do with sparkfun themselves, and I doubt they even know about the programs existence. Don’t bug them with questions. Call up Amex if you want to ask someone. Either way you end up with cool stuff. One way you get a $25 credit for buying it. Oh yeah, it also seems like you can get the credit for every Amex card you have with them that you register(!)


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DIY Rotary turntable

I have wanted to build a rotary turntable for quite a while. With it I can shoot 360 degree product shots, I can set the camera up on it and shoot panoramas. I can use it with my timelapse setup to put motion into a long shot. I also have an idea about trying to use it to build a masterlock picker!

There is a stepper motor connected to a sparkfun easydriver via an arduino (not shown) The motor has something like 1.5 degrees per step and it is geared down heavily via the rubber belt, so it is very precise.

I used a table saw to cut this notch. Not something that I would recommend for the faint of heart.
Here is the easy driver on the breadboard.

This shot shows the bottom of the board. I used a “lazy susan” bearing from Home Depot to keep the turntable rolling smoothly. One thing I did wrong is that it was mounted several times while I was sanding or grinding and I definitely got a bit of grit in the bearings.
more info after the break

Macro photography focus stacking rig

The other day I saw this link from dsvilko and thought it was a really good idea. He uses the sled from a cd or dvd player to accurately position a subject for macrophotography. If you have never tried it before, then shooting something macro usually means that there is very light coming in to the camera and it makes manually focusing something (by twisting the lens) almost impossible.

Initially I wanted to directly duplicate dsvilko’s rig, but the sled I have doesn’t have the belts traveling in the same direction as his, so there was no easy way for me to replace the dc motor with a stepping motor. I decided to just roll with the punches and stick with what I had. By limiting the amount of time the motor was on I could build a reasonable facsimile of a repeatable step. I am currently moving the sled in 20 millisecond periods.

I directly soldered wires to the existing motor’s terminals. I zip tied them to the sled and then started work on the arduino side of things. I am using a l298 h bridge motor driver to control the motor. It takes 3 wires from the arduino. Two wires control the direction of the motor, and the third turns it on.

more after the jump

Building the Bliptronome v0.1 and 0.2

So here is the followup to my last Bliptronome post. As I said I bought a bliptronic-5000 from thinkgeek over christmas break and was working on it back at home. I didn’t have very much for spare parts or tools, so I had to make due with that I had.

Here is the box it comes in. Try to contain your excitement.
monome clone from bliptronic-5000

Here is my first prototype. I learned a lot with this, not the least being that using old ide cables can be a very frustrating way to prototype. After re-wiring the arduino 3 or 4 times I finally tested the cable only to find that 5 of the pins were all grounded internally (somehow). I ended up with the breadboard here and it worked out for a test.
monome clone from bliptronic-5000

Since the ide cable failed I ended up taking the female header off of the scrap board and mounting some solid core wire to it.
monome clone from bliptronic-5000

This is the top of the the button board.
monome clone from bliptronic-5000
more gory details after the break

Cheap Monome built from a toy and and arduino – bliptronome

I’ve watched the monome videos for quite a while now, and I’ve really enjoyed them. I love how the unlabeled device looks so useful in someone else’s hands, but I know it’s really tough to learn. I have wanted one for a bit, but the makers (who seem awesome) only release small runs every once in a while, and they are generally highly (~$500) priced as well.

I saw a few links saying that you could build your own from an arduino and a bunch of gear, and that really got me interested. Over here at flipmu they have a full shopping list for building an arduino based monome clone that is called an “arduinome”, but it still looks like it comes out to almost $300 with shipping AND it is still very much a kit.

More recently I saw that some people had hacked their $40 bliptronic-5000s into arduinomes and that really piqued my interest. The hack basically uses the shift registers, buttons and leds of the bliptronic, and swaps in an arduino as the brains of the operation. The hardware is nowhere near as nice as the actual monome is, but it is approachable financially, and it’ll be useful for other things once it is connected to the arduino regardless.
Hit the jump for the details!

Vote for TinyEnormous! wired/sparkfun/ponoko contest


Sparkfun, Ponoko, and Geek dad from wired have all teamed up to create a contest for us makers. The rules are simple: design something that uses sparkfun’s parts and Ponoko’s cutting services. The top ten coolest designs get picked by a panel and then the best one gets picked by an online vote! I have submitted two ideas and I really hope at least one of them makes it into one of them made it into the the top ten! I was surprised by how few people entered, but I guess the whole line about…

Submit a photo, render, sketch or scribble on a napkin to the GeekDad pool on Flickr (and tag it ‘ponoko’) or leave a description of it in a comment below before the end of the weekend

…was too daunting for some people! Regardless, I put two entries into the contest. One is a laser cut beer vending machine that is designed to retrofit an old dorm mini-fridge into a beer vending machine(!), and the other is a physical progress bar.

Here are pictures of the (very) rough prototypes. The beer vending machine should be pretty self explanatory.


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How to ‘piggyback’ driver chips on Ladyada’s arduino motor shield

I really like the motor shield from adafruit industries. It is simple and it allows me to plug it in and start playing quickly. I usually have giant machines in my head, and the shield just wasn’t designed for those kind of motors.
You aren’t going to end up running your prius off of one of these controllers, but it turns out that you can almost double the max motor current draw just by soldering on some chips.
From Adafruit’s forums I figured out what ic’s I need to order (L293). Here is the label on the esd bag.

Now all that you need to do is solder them on top of the existing motor driver chips! As strange as it sounds, the theory has been vetted. Each one of those drivers can handle 600mA continuous. By stacking one on top of another they each handle ~600mA and you end up with ~1200mA! The motor shield has two driver ICs mounted on it, they are the two outer ones.

Here is a shot of the board. It is assembled, but it only has one motor driver chip per channel (‘channel’ feels weird there, but you know what I mean)

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Sparkfun Autonomous Vehicle Challenge

I just got back from the Sparkfun AVC. It was a blast! I shot a lot of video, but that will take a while to get processed edited and uploaded. In the meantime here are the things I thought were cool on the ‘factory tour’ with a few AVC shots thrown in.

This pond instill fear in a lot of AVC owner/operators. Strangely enough the airborne division didn’t seem to mind the water as much as the trees.

This lil guy broke down the day before the big race. Sigh. It’s not easy being autonomous.

Known for it’s blazing speed, Bluebot held it’s own. It eventually claimed first place in the DNF division!

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Missed out on Sparkfun free day? Buy it anyways!



So, like many of my readers I spent the morning watching firefox time out on sparkfun’s website. Eventually the clouds parted just in time for me to see the ticker go from 70k to 98k, to 100k. Just like that the first ever (annual?) sparkfun free day was over. I was bummed. Then I started thinking about it. Everything in my cart was something I wanted, and I did have a good time this morning, and I had a good time thinking about what I was going to get, and why. I have always thought sparkfun is a really cool company, and the fact that I can’t get this stuff for free isn’t going to stop me from buying it.


Right now there are probably a few thousand people still crashing the gates of sparkfun.com trying to get in on free day. It is over. They rewarded us with the chance to get free stuff. I personally am going to thank them by buying it anyways.


Thanks Nate, thanks Sparkfun!