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Barcode Binary Card Reader

Post author By Pete Prodoehl
Post date 2015-11-15

Sensors

I recently prototyped a device to read cards (physical cards with printing on them) for a project. I used five SparkFun Digital Line Sensor Breakout Boards attached to a 3D printed mount and wired up to an Arduino.

Card and Sensors

The cards have five blocks at the bottom, which are either black or white, representing 1 or 0. Using ones and zeroes allows us to create a binary encoding scheme, so with five positions we use 1, 2, 4, 8, 16 for the values and can represent any number from 1 to 31.

Sensor Mount

I started by grabbing the image of the sensors from the SparkFun product page and dropping them into Inkscape (sized appropriately) so I could design the barcode part of the card, and so I could design the mount for the sensors.

Sensor Mount

Once I had a 2D design in Inkscape I exported it as a DXF file and used the linear_extrude command in OpenSCAD to create a 3mm tall plate, and then added another plate. It wasn’t perfect, but it was fast. I started the 3D printer while I got to work soldering…

Sensors

Sensors all soldered up, mounted to the plate with 3mm screws, and wired to an Arduino via a breadboard. All of this is still prototyping stage. It doesn’t look pretty, but it worked and it was enough to test things out and do a demo.

Cards with Barcodes

Here’s an example of some card templates. Can you determine what number is being passed by reading it in binary? Since we’ve got 5 positions we can have 31 different cards… If you needed 63 cards, you would need 6 positions (and one more sensor.) 127 cards? That would be 7 positions and two more sensors. Any more than that and you might consider using the SparkFun Line Follower Array which has 8 sensors on a single board.

Card and Sensors

The total time to create this prototype was just a few hours from starting a design in Inkscape to 3D printing a piece, soldering up and mounting the sensors, and writing the code. (I also wrote a simple Processing application which read the serial output from the Arduino to display the card data on screen.)

Tags arduino, inkscape, openscad, processing, sensors

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Bloggers: 2015

Blogging: 2015

It’s been a long time since I’ve posted a “bloggers your should follow” post, so it’s time. I mean, I’m sure you’re content with just reading the insane ramblings at RasterWeb!, but there are some people I know who are doing some amazing sharing, or are new at the game and could use a few more eyeballs, so here’s the list… and yes, they are all maker-focused.

handverker – frankieflood.blogspot.com – Frankie Flood is responsible for the DCRL at UWM and a prolific maker and crafts-person. He shares many of his own projects (which often involve motorcycles or vehicle rebuilds) and he also shares the work of his students, and things that inspire him.

Bryan Cera – bryancera.blogspot.com – Bryan is a former student of Frankie’s and leans a lot more towards physical computing projects involving computers and electronics. He also shares project with lots of photos and great detail. Like Frankie, some of Bryan’s posts involve things he’s working on for his students. (Instructors take note: blogging is a great way to document your curriculum!)

BridgeMaker – chadbridgewater.blogspot.com – Chad is another former student of Frankie’s (sheesh!) and he’s a lot more focused on machines and machining and has a love of old tools. Like Frankie and Bryan, Chad also shares projects he works on for his students. Chad tends to do multiple posts for projects so you get to follow along with the progress. It’s better than TV!

MAINSPRING – johnmcgeen.blogspot.com – John McGeen is a co-worker, friend, and also a former student of Frankie’s (see a trend here?) John is an obsessive maker, in a good way! I somehow convinced him to start blogging many months ago, and since then I’ve been greeted with documentation of his projects and skills on a weekly basis. There’s even been a bit of cross-over where we’ve worked on projects together, which is totally awesome, in my book. John’s also a motorcycle and vehicle guy (like Frankie) but he’s always trying something new, which is very inspiring.

Digital Fabrication and Design – digitalfabricationanddesign.blogspot.com – Caitlin Driver is a current student of Frankie’s and spends her days (and nights) in the DCRL at UWM merging art and technology through digital fabrication. Caitlin is documenting most of her work in grad school — from exploration to process to finished piece — which is going to be extremely valuable in the future. (Bonus! Caitlin has another blog at caitlindriver.com/blog)

VR – vishalrana.net – Vishal is a member of Milwaukee Makerspace and one of the main organizers of Maker Faire Milwaukee, and he’s finally starting to document his projects. If you want to keep an eye on some projects you might see at the next Maker Faire, keep an eye on Vishal’s posts.

Kathy’s World – kathy.lt – Kathy is also a member of Milwaukee Makerspace and one of the main organizers of Maker Faire Milwaukee. She’s just recently started blogging but I’m hoping if we keep bugging her she’ll keep going, because she works on a lot of awesome things, and the sharing them with the world would be a good thing.

Well that was fun! All of these people are friends of mine, and they do cool things, so check them out, and hopefully you’ll be inspired to make something.

Tags blogging, makers, making

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No Signal

“No Signal” was a project I wanted to do back in 2014, but never had time to. The idea was to have a projector set up in a space with a video playing that suggested the projector could not find the input source. For anyone who has done a presentation or had to deal with a data projector, you probably know the joy of changing the inputs, waiting for the signal to sync, and even “perfecting image” messages.

It’s 2015 and we still can’t plug a computer into a projector and have it “just work”.

Since we needed some projects for the Dark Room at Maker Faire Milwaukee, I figured this would be a good fit. I quickly edited together a video (and I was suffering from a lack of sleep when I did it) that got more ridiculous as I kept adding things. I gave my projector to Bryan Cera for his “Entertainment System” project so I ended up using an old Apple Cinema Display I had on hand. The front looks very clean and stylish…

…and for anyone brave enough to look at the back, I wanted it to look ridiculous. Insert comments here about how Apple products are clean and beautiful on the surface while hiding the ugly shit so you can’t see it. I used a lot of zip ties to secure the Apple Power Brick™ to the back of the display, and also added a Raspberry Pi to play the video. There’s also an DVI to HDMI converter in the mix.

This is some very sophisticated last-minute rigging right here! (Note the masking tape that secures the SD card in place.) The video is below for you to enjoy.

Disclaimer: I may have been slightly inspired by Improv Everywhere.

Tags apple, raspberrypi, signal, video

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The Maker Movement is about 3D Printers

Post author By Pete Prodoehl
Post date 2015-10-30

Jay Silver

I’ve seen a lot of people share this post from Jay Silver titled The Maker Movement is Not About 3D Printers, which bothered me, because the Maker Movement can definitely be about 3D Printers, or Robots, or microcontrollers, or laser cutters. It can also be about sewing, and growing your own food, and building furniture, and hundreds of other things.

Why was this titled “The Maker Movement is Not About 3D Printers” instead of “The Maker Movement Is about Freedom”? Oddly enough, the second level heading is The Maker Movement Is about Freedom.

3D Printers provide freedom. They provide to individuals with a few hundred dollars the ability to design things, and make those things into real-world objects in an afternoon, at home, without having to deal with service bureaus or companies who might put restrictions on what your want to create. You can also order a bunch of parts on the Internet, get them delivered to your house, and build a robot. Was that possible 20 years ago? (At a reasonable cost, anyway?)

Maybe the jab about 3D Printers and robots was just there to create controversy, I don’t know… but it seems weird to single them out. I’ve had my ups and downs with 3D Printers, and yes, they do fail, and sometimes suck, but so do computers, and other tools, and people. Nothing is perfect… and maybe that’s a big part of the Maker Movement, recognizing that the world isn’t perfect, but realizing you can change it.

Tags 3dprinters, make, robotics

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Return of the HDPE

It’s the return of HDPE! I was recently at IKEA and grabbed a metal baking pan. I gave up on glass after the last episode, and while people suggested Silicone, I never got around to buying a Silicone pan.

Now, it’s important to remember this is recycled HDPE, and it’s not virgin material. Also, some foreign matter may get mixed in. The HDPE for this batch came from a few sheets I asked John McGeen to plane for me. He swept up the shreds and bagged it and returned it to me to re-melt. (The sweeping from the floor is probably why some foreign matter gets in.)

The bottom (the part that was touching the metal pan) shows a bit more of a “burny” look to it, being yellow, and such. That may be the difference between glass and metal. I’ll experiment more to find out.

Like the other pieces I pressed the hot HDPE between some pieces of wood. Removing the plastic from the metal pan was much easier than the glass pan. You could even consider skipping the pressing and just let it cool in the metal pan. It should shrink a little bit and pop right out.

Tags hdpe, melt, plastic