Arduino Projects: Plotters and Sensors
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This pen plotter gets nervous when observed | Arduino Blog
The whole purpose of machine automation is to eliminate human needs and errors. A CNC machine doesn’t get tired, doesn’t need breaks, and performs a task exactly the same way every time. But what if that weren’t true? What if machines experienced human emotions and let it affect their work like we do? That’s the idea behind Devlin Macpherson’s Nervous Drawing Machine.
By all outward appearances, this is just a standard two-axis pen plotter. Like many laser cutters and 3D printers, it has a stepper motors controlled by an Arduino board that follows g-code commands. A command might be something like “move the X axis 2mm to the right.” By chaining hundreds or thousands of those commands together, the machine can follow complex toolpaths that form letters, symbols, pictures, or anything else. Macpherson equipped the pen plotter with a continuously fed roll of paper so it can draw indefinitely.
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Substituting a flex sensor for an inexpensive light-dependent resistor | Arduino Blog
In order to build wearables that react to movement, most people tend to reach for accelerometers, gyroscopes, and flex sensors. But due to their higher cost, one of teacher Gord Payne’s students wanted to create a low-cost alternative that could be easily sourced and integrated into projects.
A typical glove with finger movement tracking normally incorporates flexible strips, which vary in resistance based on the extent of their deviation from the starting angle. By reading this value with an Arduino board’s analog-to-digital converter (ADC) and mapping the resistance with a formula, the total angle can be found with decent accuracy. The student’s idea, however, substituted this special material for a flexible tube that has an LED on one end and a light-dependent resistor (LDR) on the other. When kept at the starting position, all of the light from the LED is able to hit the LDR, and any bends introduced from bending the tube cause less light to reach the other side.