LVBots, a club for robot building enthusiasts in Las Vegas, held an open house the week of CES. This was the only trip [Sophi] and I took away from the conference halls of The Strip and it was a blast! The group holds meetings twice a month in a space provided by Pololu — a well-known robotics and electronics manufacturer headquartered just south of McCarran International Airport.
[Claire] demonstrating robotic closet demo and app
The mechanized racks of the automated closet
Line-following robot demonstration
Sumo robots about to rumble
Before the formal part of the gathering started there were several builds being shown off. [Claire] and [Brian] recently participated in an AT&T sponsored hackathon. Their creation is a robotic closet. The system involves moving racks of clothing which are tracked by a smartphone app. Interesting features discussed for the software include monitoring when each garment was last worn, last washed, and if it is appropriate for current weather conditions. Dig into the code in their repo.
In other parts of the room a pair of line-following robots did their thing, and a couple of sumo-bots competed to push each other out of the ring. A large group was gathered around the projector watching videos of robots of all types, brainstorming about the difficult parts, how they were overcome, and how these methods may be applied to their own build. I can attest that hanging with a group of people who are trying to cue up the most amazing robot demonstrations makes for amazing viewing!
As the organized part of the meeting began I was delighted to hear about a standing challenge from the LVbots group. The Tabletop challenge has multiple phases that serve to encourage builders to start modestly and then iterate to achieve new goals:
Phase 0: bring a robot to LVBots
Phase 1: travel back and forth without falling off
Phase 2: find an object and push it off
Phase 3: push object into a goal
[Nathan Bryant] and robot
[Joe Carson] and robot
[Nathan Bryant] was one of the two robot builders trying out the challenge on this night. He built this hexapod from balsa wood and three servo motors and was testing Phase 1. The bot includes a sensor dangling out in front of the robot to detect then the table surface is no long below. At that point it backs up a few steps, turns in place, and proceeds in the opposite direction. [Nathan] mentions that he worked out all the movements in a spreadsheet and that future firmware upgrades will dramatically increase the speed at which the bot moves. We love the audible cadence of the bot which is easily observed in the video above. At one point a leg dangles over the edge and it looks like [Nathan] pushed the bot back but I don’t remember him actually touching it so I’m calling this a trick of camera angle.
One phase further in the Tabletop Challenge is [Joe Carson]. He exhibited a wheeled robot he’s been working on that includes a gripper arm on the front. The robot looks around the table for a predefined color, in this case provided by a highlighting marker. When found the bot approaches, grips, and then proceeds to move the marker over the void where it is dropped out of existence; at least from the robot’s point of view.
There are quite a few flavors of line following robot. No matter how they’re made, most are built for speed and accuracy. The Cambot by [Jorge Fernandez] however makes use of a traditional video camera to read visual input instead of the reflective sensors we’re used to seeing in these types of robots. Because of this it lacks those swift and agile qualities, but scores points with its unique analog design, over-sized tricycle wheels, and stylish RCA jacks poking out on the side.
Coupled with a PIC 16F84A microcontroller, [Fernandez] divides the video input from the camera into 625 lines. The PIC is responsible for scanning horizontally across these lines and translating the proportions of black and white into PWM pulses. The duration these proportions are seen by the camera determines the PWM frequency fed to the left and right servo motors driving the robot.
As far as line-followers go, this is a refreshing retro approach to the concept. [Hernandez] outlines the finesse about driving his cambot on his blog (an English translation can be read here) and provides a complete schematic for those who are interested in whipping up their own quirky little machine.
Continue reading “This Analog Cambot Plays Outside the Lines”
There’s no denying it. Super small robots are just cool. [Pinomelean] has posted an Instructable on how to create a mini line following robot using only analog circuitry. This would make a great demo project to show your friends and family what you’ve been up to.
Analog circuitry can be used instead of a microcontroller for many different applications, and this is one of them. The circuit consists of two op-amps that amplify the output of two phototransistors, which control each motor. This circuit is super simple yet very effective. The mechanical system is also quite cool and well thought out. To keep things simple, the motors drive the wheel treads, rather than directly through an axle. After the build was completed, the device needed to be calibrated by turning potentiometers that control the gain of each op-amp. Once everything is balanced, the robot runs great! See it in action after the break.
While not the smallest line follower we have seen, this robot is quite easy to reproduce. What little robots have you build lately? Send us a tip and let us know!
[via Embedded Lab]
Continue reading “A Mini Op-Amp Based Line Following Robot”
We love a good line-following robot project and this really hits the spot. It’s got sharp edges, gobs of solder bridging, and look at all those jumper wires! Despite its appearance it puts in a performance that won’t disappoint.
It uses a dsPIC33 to read from half a dozen analog sensors on the bottom of the board. We’re not all that familiar with the chip’s features, but [Exapod] says it’s got an auto-scan feature he uses to read the sensors. This allows him to sample with 12-bit resolution from all six of them at about 30 kHz. No wonder the thing is so responsive in the demo video embedded below. The track he’s using is just some white printer paper with a fat circuit of black electrical tape placed in a somewhat squiggly pattern.
This is also a fun challenge with toys. Here’s one that hacks a hexapod to follow the lines.
Continue reading “Protoboard line following robot”
The Chief Knock-a-Homer robot is [Psycho Freaky’s] shout out to The Simpsons. The robot design appeared in an episode where [Homer] built [Bart] a fighting robot. Since he’s not robot builder, [Homer] actually climbed inside the shell and dished out sweet vengeance while suffering some severe injuries at the same time.
But [Psycho] has the skills necessary to make this autonomous and keep it looking just like the TV show at the same time. He has a friend with a CNC mill, and used it to cut out case parts from Masonite which were assembled with hot glue. A pair of small servos drive two wheels at the rear of the base, with a ball-bearing universal wheel centered in the front. There are also two downward-pointing sensors which lend it the ability to follow a line as seen in the video after the break.
We love the paint job, it really polishes the look. But [Pyscho] isn’t quite done yet. He plans to add an audio circuit that will give the robot the ability to play back classic sound clips.
Continue reading “Line-follower is an homage to [Homer]; plans to infringe copyrights”
Want to monitor how much a wheel has turned in your project? Then you need a rotary encoder! Here’s a way to add rotary encoding without changing the mounting method of your wheels (translated). [Jorge] added it as a way to improve the functionality of this line-following robot. It uses a paper encoder wheel which is monitored by an optical sensor.
The paper wheel consists of alternating white and black pie pieces. You can make this with a felt-tipped marker, or use a tool like the one we featured a couple of years ago to print out a disc rendered to your own specifications. This is glued to the inside of the wheel and monitored by a CNY70 reflective sensor (the same one used in that electric keyboard retrofit).
The homemade board which holds the sensor can be seen mounted on top of each wheel’s motor. It requires three wires, voltage, ground, and data. The data line is connected to the output of the phototransistor in the CNY70 package so it can be used with a microcontroller interrupt for easy integration with the firmware driving the robot.
[Jorge] goes into some detail about how the added data helps to improve the speed performance seen in the clip after the break.
Continue reading “Easy rotary encoding for your projects”
This tiny line-following robot is quite impressive. It’s [Ondrej Stanek’s] second take on the design, which he calls PocketBot 2. Just like the earlier version, this robot is small enough to fit in a matchbox, but it’s received several upgrades in this iteration.
The coin cells that ran the previous version have been replaced by a rechargeable Lithium Ion cell. The ATmega8 which controlled the first robot has been swapped out for an ATmega128 running at 32 MHz. You won’t find an IR receiver on this one either, it’s been traded for a Bluetooth module which adds a quantum leap in functionality. For instance, the graph in the upper left of this photograph shows the reflective sensor data readings used to follow the line.
There’s all kinds of great engineering in this design, which is shown off in the video after the break. One of our favorite parts is that the axles are attracted to the center of the robot by one rare-earth magnet. This keeps the rubber tires pressed against the motor spindles rather than use a gearing system.
Continue reading “Update: Tiny line-follower and more”