We have been hard at work on our latest project called Mechatron. To control our Mechatron robot as well as our Mars Rover, we designed and built our own remote control box. We developed our own communication protocol for transmitting commands from the remote control to the robot. On other projects we used iPhones and Playstation remote controllers, but in this case we wanted to build a large, metal box with lots of retro-switches and joysticks.
1. Although it wasn’t cheap, the hall-effect 3-axis joystick was critical for controlling the function of Mechatron’s specialized drive system. We originally tried a traditional analog/resistive/potentiometer-style joystick and it did not work well at all. We thought our whole project was going to fail until we realized that not all joysticks are created equal. The joystick based on the “hall-effect” principle worked perfectly for us.
2. You can’t see it in these photos, but this controller can be charged via banana jacks and re-programmed via a USB jack without having to unscrew and remove the case. The same is true for the Mechatron robot itself.
Security V is a small security robot. It’s equipped with the following capabilities:
Automatic electric gun (Airsoft pellet gun) with ammunition cage
Pan-Tilt Gun Turret
Targeting laser
FPV Camera
(3) Ping sensors for object avoidance
LED Light Strips
MP3 Sound Player
IR Human Detection Sensor
Moto Controller
Two motors
Two treaded drive wheels and two omni wheels
Arduino Mega Microcontroller
Xbee Radio for remote control
Button panel for selecting the mode
We programmed it with five different modes:
1. Roams autonomously around the house, playing R2-D2 like sounds as it explores & avoids obstacles 2. Remote Control 3. Dance Mode (Plays the song Mr. Roboto and dances around) 4. Guard Mode (enables its infrared human detection sensor and plays a police siren if anyone tries to sneak past it) 5. Shoot (shoots the gun)
Security RobotSecurity RobotSecurity Robot – Top View
After building a number of indoor robots, we decided to build an outdoor robot capable of traveling through rough terrain. We call it “Trekker.”
TREKKER ROBOT. Six wheels. Six motors. Batteries below deck. Electronics above deck.
First, we put together a six-wheel independent suspension with a separate motor on each wheel and large knobby tires. Each wheel moves up and down separately, which allows this little beast to climb up and over just about any obstacle (rocks, slopes, cats, whatever gets in its way). Here is a video of Trekker going over a large pile of books.
This is by far our funnest robot to drive via Remote Control, but this true magic of Trekker is his navigational capabilities.
We wired Trekker with a GPS chip and a tilt-compensated magnetometer (an electronic compass that works even when the robot is tilted). When Trekker first comes on, he automatically looks for and synchs with as many satellites as he can find in the sky (usually about 10-15). We programmed Trekker to determine his exact latitude and longitude position using the GPS as well as his directional orientation using the magnetometer. He then travels on his own to a series of latitude and longitude waypoints (that we get from Google Earth). Trekker’s navigational algorithm was one of our most ambitious software challenges to date. Our favorite test run is to put him in our backyard and give him instructions to drive around the big tree, down to the barn, drive around the goat pen, and return to us. He does it beautifully, all on his own, moving systematically from one waypoint to another. We also equipped him with a forward-facing sonar, which swivels back and forth on a pan servo, to avoid trees and other large obstacles along the way.
Trekker Robot – Top View – The white square in the middle is the GPS, which is used for navigation. When traveling between waypoints, the Longitude and Latitude display on the little LCD screen.
Trekker – Front View – This provides a nice view of the sonar at the front of the robot, which is used for obstacle detection and avoidance when traveling in automated mode. The magnetometer (compass) is mounted on a tall shaft at the back of the robot to keep it clear of interference from the other electronics, especially the radio.
This picture of Trekker’s underside shows how each wheel connects to a separate motor (black t-shaped things). Each motor housing is on springs and swivels so that it moves separately from the other motors.
Thanks to the shock-absorbing independent suspension of each of its six wheels, Trekker rolls over pretty much anything
Software Modes
We programmed Trekker with a several different modes he can operate in:
Navigate autonomously to a series of user-provided Longitude/Latitude Waypoints
Roam autonomously using swiveling front sensor to avoid obstacles and find best path
Radio Control (RC) – display commands and motor speeds on LCD
Radio Control (RC) – display longitude, latitude, and heading on LCD
We would like to introduce our flying drone robot. We can fly this robot using Remote Control or it can fly itself using sonar, an on-board GPS, and following longitude/latitude waypoints. We have experimented with various frame designs and electronics, so you’ll see some variation in the pictures. Be sure to check out the video of of me piloting the flying robot.
How We Came To Build a Flying Robot Drone
One day, we asked ourselves, “What kind of robot would you like to build next?”
We both answered, “I want to build a robot that flies!”
We knew it was going to be really hard, but we decided to give it a try. We set out to learn what it was going to take to build a robot that flies. We researched our options, purchased the various motors, propellers, and electronic components we thought we needed, and started soldering. As our initial design came together, we began cutting, drilling, and assembling the various aluminum pieces for the frame, which we knew would have to be both light and strong.
The Features and Design
We decided on a quad rotor design, which is a helicopter-like-thing with four propellers. The left and right motors use normal “puller” propellers and turn counter-clockwise. The front and back motors use “pusher” propellers and turn clockwise. This helps counter-act the torsional forces associated with rotor craft.
The core of the robot’s electronics is a special Arduino microcontroller board specifically designed for auto-piloting drones. This is combined with a special Inertial Measurement Unit (IMU) sensor shield that provides a 3-axis gyro, 3-axis accelerometer, barometric pressure, and other various other avionics sensors so that the robot can sense its tilt, pitch, and yaw in three-dimensional space at all times. The software reads the robots orientation and feeds voltage to each of the motors in proportion to the power that is needed to keep the robot level at all times. This way, the pilot focuses on the direction and speed he wants to go, rather than spending all his time struggling to keep the robot from flipping, spinning, or rolling.
Once we flew and crashed our first design, we made some improvements and tried again. Then we crashed again, made some more improvements, and so on. None of our robots have required more trial and error than this one. But step by step, improvement after improvement, our robot got better and better. Today, it flies very well, has many neat features, and thanks to repeated practice, is relatively crash resistant.
We usually fly the robot using an RC Transmitter. However, it also has many autopilot drone features that we enjoy experimenting with. For example, the robot has an automatic take-off and landing sequence. The robot also includes a downward-facing sonar so that the robot knows its exact altitude at all times. By flipping a switch on our transmitter, we can put the robot in “hold altitude” mode, which tells the robot to automatically and constantly adjust the motors to remain at a constant distance from the ground as we fly it around.The robot is also equipped with a GPS chip so that it knows its exact longitude and latitude at all times. The robot can also follow a series of waypoints uploaded to the microcontroller from Google Earth. It turns out that we were not the only ones trying to build a robot that flies. We have joined with a whole community of people on the Internet (DIY Drones) who enjoy building and flying their own robot drones.
The Mini Flying Drone
We have also built a Mini Flying Drone. Click here to see details.
Mini Quadrotor Drone Robot
The upgraded Black Hornet mini drone
The Future
Although our drones are flying quite well, there is still plenty more we want to do. We look forward to lots of fun and experimentation. We’ve spent most our time building, flying, and improving the robot’s frame and capabilities, but in the future we hope to do more with First Person View (FPV) flying using our video goggles, high-definition arial photography, automatic navigation, and more.
Click here to see our latest flying robot drone, which we made out of carbon fiber.
Flying Drone Robot – Technical Specifics
Aluminum Frame: Beatty Robotics
Aluminum, Hardware, and other materials: McMaster-Carr
Microcontroller: ArduPilot Mega (i.e. Arduino Mega Autopilot board)
Avionics sensor board: ArduPilot Mega IMU Shield
Electronic Speed Controllers: (4) m2mPower
Motors:(4) jDrones
Propellers: (4) EPP 10×45
Radio Control Transmitter and Receiver: Futaba
Battery: 12v 3-cell 20C LIPO
Magnetomer: DIY Drones
GPS: MediaTek
High Definition Camera: GoPro
VideoTransmitter: ImmersionRC
FPV Video Goggles: FatShark
Special thanks to the Do-It-Yourself Drones community, especially Chris Anderson, Jani Hirvinen, and the other guys involved with DIY Drones. You guys helped us make our dream of a flying robot a reality. Fly on!
