In this issue:
• Circular engineering: making cups from food
• Tech Tip: Calibrating of Potentiometers
• Application: Control of All Terrain Vehicles
• and more.

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   Circular Juice Bar Squeezes Juice and 3D Prints Cups From Oranges

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When I first heard of it, I asked, "what is a circular juice bar, and why is its engineering notable?" The answer has two parts. First, it is a self-contained circular economy machine: manufacturing -> consumer use -> recycling. Second, it is a machine that demonstrates a practical use for 3D food printing.

This juice bar is about 10 feet in height, has rails that feed 1,500 oranges into a cutting, peeling and juicing machine. While the oranges are being squeezed, the peels are collected. The orange peels are dried, milled and mixed with polylactic acid then heated and melted into filaments "off-line," then loaded back into the juice bar. The filaments are fed to a 3D printer in the juice bar that prints the cups. After users watch their cups being printed, they are then filled with freshly squeezed orange juice for drinking.

CRA-Carlo Ratti Associati, in partnership with global energy company Eni, has developed this experimental Circular Juice Bar and called it "Feel the Peel."

To quote from their website: "The principle of circularity can be an inspiration for tomorrow's everyday life objects," says Carlo Ratti, founding partner at CRA and director of the Senseable City Lab at the Massachusetts Institute of Technology: "Working with Eni, we played around (with) a machine that helps us to understand how oranges can be used well beyond their juice. In the next iterations of these projects, we might add new functions, such as printing fabric for clothing."

Credit: A project by CRA-Carlo Ratti Associati for Eni

When A Calibrated Potentiometer Is Needed (And How To Calibrate One)

A potentiometer (referred to as a pot or pots for a plurality of them) is often used to translate a specific distance a part moves into a numeric value. This value is output from the pot as a voltage or — with additional integrated circuitry — an active output signal. Which output type it is depends on the device selected. Passive pots transform linear or rotary movement into a voltage. For this tech note we will limit our discussion to linear pots, though the principles are the same for rotary potentiometers.

For a linear pot you need to be able to count on an output value that changes proportionally with the movement. The amount the pot deviates from a 1:1 proportion as it travels from minimum to maximum is known as linearity error. Most passive pots from all the manufacturers we are familiar with will only meet their linearity error specifications if they are calibrated.

Active position sensors are pre-calibrated by the manufacturer.

To read the rest of this article including a step by step procedure, CLICK HERE

All Terrain Vehicle Controls
A custom aftermarket all-terrain-vehicle manufacturer needed a reliable and accurate position sensor they could use for all position-related controls to allow their vehicles' steering, brakes, throttle, gearshift and other motion accessories to be controlled via a joystick for disabled persons, while a non-disabled person is seated next to the disabled driver ready to switch to stock controls and take over, if needed.

Novotechnik's TX2 met their requirements and was easily incorporated into each of their different vehicles' position control applications. Position sensing of steering, throttle, brake, gearshift and a moving ramp were achieved by utilizing right-sized length TX2 position sensors for each of the moving controls. The manufacturer elected to use a 0 to 10 V output for each sensor. Each sensor is wired to a custom control module to provide feedback on actual position. The vehicles joy sticks are also wired into the same control module that is programmed to compare joystick position with control positions for steering left or right as well as throttle and brakes by moving the joystick forward or back. Click here for more information on the TX2 Series sensor product used in this application.

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