Amazingly Detailed Robotics Ground Vehicle Guide

[Andrey Nechypurenko] has put together an excellent design guide describing the development of his a20 grou1nd vehicle and is open sourcing all the schematics and source code.

20150627_180534One of [Andrey]’s previous designs used a Pololu tracked chassis. But this time he designed everything from scratch. In his first post on the a20, [Andrey] describes the mechanical design of the vehicle. In particular focusing on trade-offs between different drive systems, motor types, and approaches to chassis construction. He also covers the challenges of using open source design tools (FreeCAD), and other practical challenges he faced. His thorough documentation makes an invaluable reference for future hackers.

[Andrey] was eager to take the system for a spin so he quickly hacked a motor controller and radio receiver onto the platform (checkout the video below). The a20s final brain will be a Raspberry Pi, and we look forward to more posts from [Andrey] on the software and electronic control system.

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Sparkfun’s AVC 2014: Robots, Copters, and Red Balloons of Death, Oh My!


Registration is open for Sparkfun’s 2014 Autonomous Vehicle Competition (AVC)! Every year the fine folks at Sparkfun invite people to bring their robots, rovers, and drones  to Colorado to see who is the king of the hill – or reservoir as the case may be. We see plenty of robots here at Hackaday, but precious few of them are autonomous. To us that means capable of completing complex tasks without human intervention. Sparkfun has spent the last five years working toward changing that. Each year the robots get more complex and complete increasingly difficult tasks.

The competition is essentially a race through the Boulder reservoir. Time is key, though there are multiple ways to gain bonus points. For aerial vehicles there are two classes: fixed and rotary wing. Planes fall under the fixed wing category. Helicopters, gyrocopters, tricopters, quadcopters, and beyond fall into rotary wing. We’re holding out hope that e-volo shows up with their Octadecacopter. Ground vehicles have a few more class options. Micro/PBR class is for robots with a build cost less than $350 total, or small enough to fit into box that’s 10″x6″x4″. The doping class is unlimited. Sparkfun even mentions costs over $1kUSD+, and weights over 25LBS. Non-Traditional Locomotion class is for walkers, WildCats and the like. Peloton is Sparkfun’s class for robots that don’t fit into the other classes.

Sparkfun is also making a few changes to the course this year. A white chalk line will be drawn through the course, so robots don’t have to rely on GPS alone for navigation. We’re hoping to see at least a few vision systems using that chalk line. Aerial robots will have to contend with three “Red Balloons of Death”. Robots can navigate around the balloons without penalty. The balloons can be bumped or even popped for bonus points, but the robot must do this with its own body. Projectile weapons are not allowed. To say we’re excited about the AVC would be an understatement. As much as we enjoy watching the big players at competitions like the DARPA Robotics Challenge, we love seeing individuals and small teams of hobbyists compete every year at the AVC. Click on past the break for Sparkfun’s AVC 2013 wrap up video.

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Mustachioed Rover Simultaneously Manly, Adorable

[Rick], an Adafruit learning system contributor, is excited by the implications of STEM’s reach into K-12 education. He was inspired to design Red Rover, a low-cost robot that can be easily replicated by anyone with access to a 3-D printer.

This adorable autonomous rover is based on the adafruit Trinket microcontroller, but will also rove under the power of an Arduino micro. It really is quite simple—the Trinket drives two continuous rotation micro servos and pretty much any flavor of rangefinder you like. [Rick] tested it with Parallax PING))), Maxbotix, and Grove sensors, and they all worked just fine.

What’s truly awesome about Red Rover are the track treads. [Rick] initially experimented with flexible filament. While he had good results, it was not a cost-effective solution. What you see in the picture and the short video after the break are actually rubber bracelets from Oriental Trading.

The plastic part count comes in at seven, all of which can be printed together at once. [Rick]’s gallery includes both small and large chassis and three different servo mounts. The Red Rover guide builds on other adafruit guides for Trinket general use, servo modification, and Trinket-specific servo control.

Update: Added [Rick]’s demo video after the break!

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Wireless rover with Android control


[Radu] spend the first portion of this year building and improving upon this wireless rover project. It’s actually the second generation of an autonomous follower project he started a few years back. If you browse through his old postings you’ll find that this version is leaps and bounds ahead of the last.

He purchased the chassis which also came with the gear-head motors and tires. Why reinvent the wheel (har har) when you’ve got bigger things on your plate? To make enough room inside for his own goodies he started out by ditching the control board which came with the Lynxmotion chassis in favor of an AVR ATmega128 development board. He also chose to use his own motor controller board. Next he added a metal bracket system to hold the battery pack. Things start to get pretty crowded in there when he installed his own Bluetooth and GPS modules. Rounding out his hardware additions were a set of five ultrasonic sensors (the grey tubes on top), a character display, as well as head and tail lights. The demo video shows off the control app he uses. We like that tic-tac-toe design for motion control, and that he added in buttons to control the lights.

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GSM controlled car without needing a microcontroller

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.

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Arduino rover evolves to a trike design

[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.

Arduino rover doubles up on obstacle avoidance

[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.

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