Nope, no microcontroller here, just a full-blown cellphone used as the brains of this little robot. The secret behind how it works is in the sounds the phone makes. The touch tones, known as DTMF, are monitored by the circuit mounted on the front half of the chassis and are responsible for driving the motors.
[Achu Wilson] built the circuit around an MT8870 chip which decodes the DTMF sounds and uses the BCD output to feed some logic chips. A 4 line to 16 line decoder and an inverter chip format the signals for use as inputs to the L293D motor driver. The video after the break shows him driving the rover directly by pressing number on the phone (like a tethered remote control). But he mentions that it’s possible to call the phone and press the numbers remotely. We assume you need to connect the call manually as we see no way to automatically answer calls.
This is certainly a fun way to play around with the DTMF protocol.
Continue reading “GSM controlled car without needing a microcontroller”
[Eduard Ros] wrote in to show off the latest version of his Arduino powered autonomous rover (translated). You may remember seeing the first version of the build back in June. It started with a remote control truck body, adding an Arduino and some ultrasonic sensors for obstacle avoidance.
The two big wheels and the pair of sensors look familiar, but most of the other components are a different from that version. The biggest change is the transition from four wheels to just three. This let him drop the servo motor which controlled steering. At first glance we though this thing was going to pop some mad wheelies, but the direction of travel actually drags the third wheel being the larger two. The motors themselves are different, this time depending on gear-reduced DC motors. The motor H-bridge is the same, but [Eduard] used a simple transistor-based inverter to reduce the number of pins needed to activate it from two down to just one. He also moved from an Arduino Uno to a Nano to reduce the footprint of the controller.
[Eduard Ros] wrote in show off his first attempt at building an autonomous rover (translated). As with many of these projects, he started with the base of a remote control toy truck. This solves so many mechanical issues, like steering, locomotion, and power source.
He just needed a way to control the vehicle. The recent LayerOne badge hacks either did this through the wireless controller protocol or by adding an Arduino directly to the vehicle. [Eduard] chose the latter, and also included obstacle avoidance sensors in the process. We’ve seen quite a few that use these ultrasonic rangefinders. He decided to go a different route by adding two of them rather than scanning by mounting one on a servo motor.
The video after the break shows the vehicle successfully navigating through a tight space. This makes us wonder how much data can be processed from the stationary sensors? We’re not familiar with how wide the horizontal sensitivity is on the devices. If you have some insight, please share you knowledge in the comments section.
Continue reading “Arduino rover doubles up on obstacle avoidance”
[Justin] wrote in to tell us about the rover which his CalTech team has entered in NASA’s Exploration Robo-Ops Competition. Their time to shine is later this week, but you can see some of the test footage after the break.
The operator pictured above is using a controller which is a scale model of the manipulator arm, with two cameras giving feedback. One of those monitors shows a feed from the arm itself, providing a view of the gripper. The other feed is a wide shot of the working area from the body of the robot. The arm has six degrees of freedom actuated by servo motors. The controller is a replica of the arm laser cut from acrylic. At each joint there’s a potentiometer whose value is used to establish the position of the frame.
At first we thought that this would be more fatiguing and less convenient than using a gaming controller. But as we look at the dexterity of the arm it becomes obvious that joysticks and buttons would just make things more difficult.
Continue reading “CalTech’s manipulator-arm equipped robot”
That black box is hiding all kinds of goodies that make this rover a hacking playground. [Andrey] built the device around a BeagleBoard, which offers the processing power and modules that he needed to make the rest of it work.
The control unit shrinks the pilot down to the rover’s size, using a cockpit that has a steering wheel and other controls, and a monitor playing the stream from the camera on the front of the bot. It has a WiFi adapter which allows control via the Internet. The camera, which can be rotated thanks to its servo mounting, feeds the video to the BeagleBoard where it is compressed using the h264 codec (more about that and the cockpit here) to lighten the streaming load. You’ll also find an ultrasonic rangefinder on the front for obstacle avoidance, and a magnetic compass for orientation information. Finally, a GPS bolsters that data, allowing you to plot your adventures on the map.
It’s great, but it will cost you. Material estimates are North of five hundred Euros!
We never really get bored with remote-controlled rovers around here, especially when they involve reusing some old hardware as well as lasers. [Tycoon] wrote in to share his creation, which he has dubbed “Texas Ranger”.
Texas Ranger is built around an old Linksys WRT54GL router, which provides the rover’s WiFi connectivity as well as the serial interface through which everything else is controlled. The rover features a pair of PIC microcontrollers, which handle all of the servo control as well as telemetry calculations.
An onboard camera gives the operator a driver’s seat view of the action, allowing for precise control of the vehicle. Laser triangulation is used to help measure object distance, and a pair of airsoft pellet guns straddle the camera for whenever [Tycoon] feels like making his presence known. One feature we are especially fond of is the pair of Wii nunchucks which the rover uses to monitor its position. Always aware of its operating angle, it auto-adjusts the camera to compensate for uneven surfaces, guaranteeing that [Tycoon] doesn’t have to tilt his head to see straight.
Keep reading to see a quick demo video he shot of Texas Ranger in action.
Continue reading “Wireless rover has two guns…one for each of ya”
[Jad] recently wrote in to share a pair of projects that have been keeping him busy as of late.
The first is a sound localization system not unlike one we showed you a few weeks ago. The difference is that his system displays the sound source via a set of LEDs rather than by motion, making it far less prone to interference by things like servo noise. His system uses four identical circuits, each of which are wired to a separate analog input on the Arduino. Each channel is adjustable, making it easy to tweak how the system responds to a particular sound.
His second project is a sizable robot built on the Motoruino platform. His contraption features several stacked control boards that handle the bots locomotion as well as camera control. It connects to his computer via a Bluetooth module that boasts a 1 mile range, allowing him to control everything from his PC. [Jad] is using the robot as a prototype for a much larger scale creation, and he says that his current focus is getting the robot to track and follow objects automatically using the on-board camera.
Continue reading to see a small preview of his bot’s progress so far.
Continue reading “Sound localization and a treaded rover”