The Make It Last Build Series Newsletter, Build #3, Dispatch #1
Welcome to the third installment of the Make It Last Build Series, sponsored by Microchip and Energizer.
This time around, we're going to be looking at using a low-power PIC microcontroller to drive a couple of motors in a Drawing Machine that will draw lines and curves on a wall. This project will build on the basic microntroller circuits developed in the first two builds of this series, but you can also jump right in even if you haven't participated in the previous builds.
We're also going to do something different with the prize giveaways this time. We're making it much easier to be eligible for the prizes (which include a Microchip Explorer 16 Demo Board and Maker Shed gift certificates). To be eligible, all you have to do is post your photos to the MAKE Flickr pool and take them #makeitlast. That's it! We'll be doing a drawing based on those tagged entries.
As always, see the Build Series landing page for full details, prizes, and info about the first two builds in the series.
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Introducing the Drawing Machine
The Drawing Machine is based on an installation that I saw in 2005 at the AS220 community arts center by the artist Tristan Perich
. Tristan had attached two spools of monofilament to some stepper motors; each end of the monofilament was tied to a simple binder-style paper clip that held a black Sharpie marker against the wall. As the two stepper motor-controlled spooled turned, they pulled the Sharpie back and forth along the wall to draw randomized patterns guided by a program written in Processing and running on an attached Mac.
I found the the idea of using gravity to help constrain the movement of the marker -- instead of some kind of rigid x and y axis armature -- to be very appealing. The same kind of triangulated wall drawing technique was used prpeviously by Jürg Lehni's Hektor
spray painting output device, which I am sure influenced Tristan's piece. We'll be making a Drawing Machine using the same mechanical technique (a Sharpie hanging from two motor-controlled spools), but we are going to make ours an embedded device that is not dependent on a computer for the algorithm or motor control. In later segments we'll explain the math and mechanics in more detail; for now, you should know that we're building a machine that can draw on walls.
Below are a couple of images created by the Drawing Machine:
The build process will follow these steps:
1. Building the stepper motor driver circuit
2. Assembling the drawing surface
3. Coding the motor drivers
4. Writing custom embedded drawing applications
We'll be providing the code for basic "move to" and curve drawing functions. There's all sorts of crazy algorithimic sketching that can be done with the Drawing Machine; we'll be highlighting the most interesting on Make: Online when the project is finished.
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Gathering the Parts
Here's a list of the parts that we will be using to build the drawing machine. Some of the parts can be substituted with other materials you have on hand; the stepper motors, for instance, can be salvaged from a couple of old ink jet printers. When substituting motors, try to get the datasheet because you may need a different power supply and wiring configuration.
* Soldering iron
* Lead-free solder
* Shear wire cutters
* 18lf25k22 processor (Digi-Key PIC18LF25K22-I/SP-ND, $3.14)
* 1x 1uF bypass capacitor (Digi-Key P5174-ND, $0.20)
* 1x 10k resistor (Digi-Key 10.0KASCT-ND, $1.10/10)
* 5x 1k resistor 1/4 W (Digi-Key P1.0KBACT-ND, $.09)
* 32.768 kHz crystal (Digi-Key 631-1205-ND, $0.48)
* 2x 22pF cap (Digi-Key VY1220K31U2JQ63V0, $0.64)
* 2x H-Bridge IC SN754410 (Digi-Key 296-9911-5-ND, $2.33)
* 4x 100uF capacitor (Digi-key P5123-ND, $.20)
* 1x MCP1702 low dropout regulator (Digi-key MCP1702-3302E/TO-ND, $.60)
* 4x switching transistor (Digi-key PN2222AD26ZCT-ND, $.47)
* 1x AC/DC Power Supply 5V 2.5A (Jameco 252736, $14.95)
* 2x spools of 20' 24AWG 4 Solid Conductor Intercom Wire (Radio Shack #278-858, $7.69)
* .1" male headers (Digi-Key A26509-40-ND, $1.60)
* 28-pin chip socket (Digi-Key 3M5480-ND, $0.33)
* 2x Stepper motors 400 steps/revolution (Jameco 1581231, $19.95)
* Protoboard (RadioShack 276-170, $2.99) or (Digi-Key 438-1022-ND, $13.78)
* 2x 3mm red LED (Digi-Key 754-1218-ND, $0.10)
* 2x 3mm green LED (Digi-Key 754-1217-ND, $0.10)
* A sharpie
* An binder clip
* Tape measure
* Monofilament fishing line
* Masonite or plywood scraps
* glue and tape
* drywall screws
* 2x small nylon spacers
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Microchip Discount Code
Want to pick up a PIC programmer or development kit? As part of this series, Microchip is offering a 20% discount on the following development tools:
* PICkit3 Debug Express
* ICD3 In-Circuit Debugger
* XLP 16-bit Development Board
* F1 Evaluation Platform
* F1 Evaluation Kit
If you've been thinking about getting started with PIC programming, this could be a great opportunity to get a good deal on a programmer. To request a discount code, send an email to firstname.lastname@example.org.
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