Kickstarter Backer Alert with Stats Scroller, using Arduino Yun

The Arduino Yún is a curious addition to the Arduino family. There is a fairly widespread community surrounding the Arduino concept, platform and software. There's another popular community dedicated to hacking and improving inexpensive wireless routers, which often run Linux. The Yún combines the two...it's basically an Arduino Leonardo housed on the same PCB as an Atheros AR9331 wireless router (commonly found in TP-Link and other popular hackable routers). They're connected through a serial port and run independently, but the Linino team has developed a few ways to make them team up on some tasks.

Recently, we created our first Kickstarter campaign (RGB LED Shades). It's very exciting to see the "New Backer Alert!" emails roll in, and the notifications pop up on a smartphone. But we wanted to see our Kickstarter stats at a glance, and be notified whenever we have a new backer. The Linux side of the Yún can run scripting languages such as Python to scrape website data and control an LED marquee sign, and the Arduino side can control some I/O for an impossible-to-ignore new backer alert.

Read the full Instructable here: http://www.instructables.com/id/Kickstarter-Backer-Alert-with-Stats-Scroller-using/

Submitted by Garrett on Tue, 10/14/2014 - 14:52.

Musical Fish (MSP430 Captouch & Bare Conductive Paint)

This is a short article demonstrating an experiment with Bare conductive ink and the MSP430's capacitive sensing hardware.

I've experimented with various capacitive sense methods previously; the most common uses one pin to charge up an electrode, while using another pin to measure the amount of time needed to charge up to the logic high threshold level of an input pin. A couple of similar approaches are illustrated here: http://www.ti.com/lit/an/slaa363a/slaa363a.pdf

An alternate method is available on several of the MSP430 value line microcontrollers (G2xx2, G2xx3, FR58xx, FR59xx). In addition to the typical pin peripheral functions, they include a relaxation oscillator circuit that includes pin capacitance to set the frequency. By measuring the number of oscillations in a given time period, a small change in capacitance can be measured...enough to detect whether a finger is touching an electrode.

Photo Jan 04, 1 43 12 AM (HDR)

Bare Conductive makes a carbon-bearing paint that is fairly conductive, and available in pen form. Combined with capacitive sensing, it is possible to draw an interface on a sheet of paper, and use it as input to a microcontroller. For this experiment, we used it to play a few notes from a speaker and make a very basic piano-like instrument.

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Submitted by Garrett on Sun, 01/19/2014 - 13:58.

AF_XPort and lighttpd

Recently I was building a project for a client, who needed an internet-controlled display device. For quick development time and minimal budget, I selected an Arduino Duemilanove, XPort Shield, and XPort Direct from Lady Ada's Adafruit store. Soldered everything together, tested and configured the XPort, everything worked. Then I wrote the necessary code to request data from a web server, that all worked too.

Finally I took the project down to the client's office in Mountain View and set it up...didn't work. I ended up working on the project for about four hours trying to get it running (minus some tricky subnet issues...use increments of 8 bits on an XPort). The client was using lighttpd to serve the display data, and I had been using Apache for testing. HTTP is HTTP, right? It should work on either? It didn't. I set up an Apache server on my laptop and everything worked great...point the Arduino sketch back at the client server, nothing worked. I kept getting "501 - Not Implemented" errors from the web server. If I opened up a telnet session directly to the web server and manually typed in the request the Arduino was sending, it worked.

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Submitted by Garrett on Tue, 03/17/2009 - 17:19.

Quick cable tester

Cable tester

I got a batch of cables that had a few bad wires in them, so I needed to test every cable. Checking all the wires with a multimeter was out, so I built this simple cable tester out of a proto board, some headers, an LED, a resistor, and some wire. It just completes a circuit through all the wires in a cable; if any wire is bad, the LED will not light. Simple concept, but it allowed me to test about 300 cables in about half an hour. A video of a few cable tests is below:

Submitted by Garrett on Mon, 01/12/2009 - 22:54.

It worked, ok?

Homebrew PCB saw with dust removal

This was pretty ugly. I needed to cut a bunch of copper-clad FR4 into thin strips for my LED array project. 144 1/4" strips, to be precise. I wasn't going to use the metal shear at TechShop, since fiberglass is pretty abrasive. I was also worried the pinching effect would wrap copper around the edges and short the two sides. Anyway, I lashed together a mini table saw with a Dremel, diamond wheel, hot glue, plywood, and duct tape. Note the Shop Vac dust removal system. It actually worked quite well, cutting about 120 feet of PCB material and I didn't notice any decline in cutting ability.  Read more»

Submitted by Garrett on Sun, 04/27/2008 - 01:18.

PVC Laundry Hamper + Towel Rack

I decided to make a laundry hamper for my bathroom last weekend. For some reason I didn't want to just buy a hamper, I guess I had specific ideas about durability, shape, and size that weren't available. I also wanted a place to put my towels, and I don't think any hampers have built-in towel racks, and no towel racks have a place to put a hamper. Home Depot is within sight of my front door, so I walked over and wandered the aisles with the familar blank expression of home-improvement pondering. I walked back with 40 feet of 1/2" PVC tubing, various connectors, zip ties, and plastic garden mesh. The result in the photo took about 1-1/2 hours. Aesthetics aside, it definitely works, doesn't take up much space, will never rot or warp like my original wood construction idea, is a little bigger than expected but will be able to hold all my laundry even on a day I wash blankets. PVC tubing is only like $1.89 per 10 foot piece, so it's a cheap construction material and pretty strong in lengths shorter than 3 feet.

Submitted by Garrett on Sat, 04/05/2008 - 09:29.