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diyspaceweek 1 jbr2 short Mars Bot: Adding Science to Robotics

A Mars-Bot will include the drive and steering mechanisms of a conventional competition robot, plus a wireless video cam and various sensors.

A Mars-Bot will include the drive and steering mechanisms of a conventional competition robot, plus a wireless video cam and various sensors.

Science fairs that involve engineering, physics, astronomy, and chemistry have declined in recent decades, while robotics competitions have rapidly grown in popularity. These contests teach students about electronics, mechanical engineering, and teamwork while providing plenty of fun in the process.

After watching a number of robotics competitions, I’m confident they can be expanded to include some science. Here’s my proposal for a new kind of robot competition: Mars-Bot, a simulated space mission.

Designing a Mars-Bot Competition

A robotics competition based on a simulated space mission can use various scenarios to implement scientific techniques. A suite of sensors and samplers will transform a standard robot into a sophisticated Mars-Bot that is guided across an imitation Martian landscape by a student mission team. Each Mars-Bot will be required to perform a minimum number of tasks after it disappears behind a dark curtain concealing the Martian landscape from the mission team. Only the audience on the other side of the curtain will be able to see the Mars-Bots as they execute their missions. Each team must rely on video images sent back by its Mars-Bot to navigate across the Martian terrain, complete its mission, and return through the curtain.

Before the competition, each team will receive an image of the Martian landscape, as if taken from a satellite, that identifies landmarks. A grid laid over the image will provide dimensions, and the bot must visit and sample or measure the landmarks. If the competition is indoors, a bright overhead light can represent the sun. Scoring will be based on the number of successful measurements and samples each Mars-Bot returns, with ties broken by speed. Each team will create comprehensive mission reports and data analysis to receive academic credit.

Video Camera(s)

The most indispensable sensor on each Mars-Bot will be at least one wireless color webcam. The basic setup will have a stationary mount that looks straight ahead. More sophisticated Mars-Bots will feature a webcam that can rotate to better survey the landscape, find assigned goals, and provide visual clues when samples are collected. The camera itself can also report back data indicated by readouts or instruments in its field of view.

Countless simulated Mars  landscapes can be imagined. This indoor version can be set up in a basketball court  or auditorium.

Countless simulated Mars landscapes can be imagined. This indoor version can be set up in a basketball court or auditorium.

Simulated Dust Storm

Mars is known for its vast dust storms. A fan blowing dust across the path of a Mars-Bot could test the ability of moving parts to survive a blast of grit. The reduction in electrical power that occurs when dust falls on a Mars-Bot’s solar panel can also be measured. However, wind can remove accumulated dust from a Mars-Bot too, so the landscape might include a fan that blows clean air across the bot. If blowing dust is not feasible, then a fog machine could simulate a dust storm.

Wind Speed Sensor

A Mars-Bot should measure the speed of any wind it encounters. A fan or propeller, mounted on the shaft of a small DC motor, can act as an analog wind speed sensor. When wind rotates the motor’s armature, a voltage proportional to the rotation rate will appear across the motor’s terminals. Mounting a disk on the shaft of a propeller can make a digital wind speed sensor. Glue a small magnet to the outer edge of the disk, and mount the assembly so that the outer edge of the disk rotates past a Hall effect sensor. The Hall sensor will provide a voltage pulse each time the magnet rotates by it. If the weight of the magnet causes the rotating disk to stall, 2 or 3 additional magnets can be mounted around the disk to balance it. Calibrate the sensor by placing it adjacent to a commercial, handheld wind speed sensor at various distances from a fan.

Robotics competitions show how students can learn about electronics, mechanics, and teamwork while having fun in the process.

Robotics competitions show how students can learn about electronics, mechanics, and teamwork while having fun in the process.

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Haze

Dust blown high into the Martian atmosphere can cause long-lasting haze. In an indoor competition, periodic dimming of the artificial sun can simulate haze, while passing clouds will create the same effect during an outdoor competition. A photodiode or solar cell can detect the reduced light; mount it behind a plastic diffuser to ensure it receives light no matter the artificial sun’s location.

Temperature

The temperature during a mission will slightly change with wind, haze, and cloud conditions. It can be easily measured using a thermistor or integrated temperature sensor, or with an infrared thermometer, which can also scan the temperature of various objects along the mission course.

Spectrometer

The colors of rocks, sand, and soil provide important clues about their composition. The Mars-Bot’s video camera can be used as a simple 3-color spectrometer. Photo processing software can analyze individual video frames to express the relative intensity of the blue, green, and red wavelengths of the simulated Martian landscape. A Mars-Bot mission protocol might require a 3-color analysis of various features in 3 separate video frames collected during the mission.

Sand and Pebble Sampling

An especially important part of a Mars-Bot mission is to collect geological samples and return them for analysis. The mission controllers would use their video link to steer their Mars-Bot to the sand and gravel sites along the course. The mechanical features of the current generation of competition robots can be easily modified for sand and pebble sampling.

Borer to Collect “Rock” Sample

An especially interesting task will be for a Mars-Bot to use a boring tool to collect a sample of material from a mock boulder. The mission team will steer their Mars-Bot to the boulder, bore a sample, and stash it for the return trip.

The boulder might be fashioned from a thin but rigid sheet of wood or other soft material that can be easily penetrated by a standard 1/2″ to 1″ battery-powered hole saw, which resembles a short steel cup with saw teeth around its rim, encircling a standard bit mounted in a drill chuck. The business end of the drill bit extends beyond the saw teeth to provide a pilot hole so the circle saw stays on target during the cutting process. A standard battery-powered drill fitted with a 1/2″ to 1″ hole saw could be mounted on the front of the Mars-Bot and switched on and off by a radio-controlled relay connected across the drill’s power switch. In my experience, a circle of wood removed by a hole saw stays inside the saw until it is manually removed, so the saw itself should hold and retain one or two thin samples. To prevent injuries to the mission team and onlookers, the exposed circle saw should always be covered by a red plastic cup with a red safety flag unless the saw is being tested or the Mars-Bot has begun a mission.

These are just a few ideas; I would love to hear yours. I’m hopeful that science-oriented Mars-Bots will significantly expand the hands-on educational experience provided so well by robotics competitions. Share your Mars-Bot competition ideas in the comments below or continue the conversation with #marsbotcomp.

Forrest M. Mims III

Forrest M. Mims III (forrestmims.org), an amateur scientist and Rolex Award winner, was named by Discover magazine as one of the “50 Best Brains in Science.” His books have sold more than 7 million copies.


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