This Analog Cambot Plays Outside The Lines

October 18, 2014 by Sarah Petkus 12 Comments

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.

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THP Entry: A 6502 SBC Robot (On Multiple Boards)

August 16, 2014 by Brian Benchoff 18 Comments

SBC

Robots have always been a wonderful tool for learning electronics, but if you compare the robot kits from today against the robot kits from the 80s and early 90s, there’s a marked difference. There are fairly powerful microcontrollers in the new ones, and you program them in languages, and not straight machine code. Given this community’s propensity to say, ‘you could have just used a 555,’ this is obviously a problem.

[Carbon]’s entry for The Hackaday Prize is a great retro callback to the Heathkit HERO and robotic arms you can now find tucked away on a shelf in the electronics lab of every major educational institution. It’s a 65C02 single board computer, designed with robotics in mind.

The 6502 board is just what you would expect; a CPU, RAM, ROM, CPLD glue, and a serial port. The second board down on the stack is rather interesting – it’s a dual channel servo board made entirely out of discrete logic. The final board in the stack is an 8-channel ADC meant for a Pololu reflective sensor, making this 6502 in a Boe-bot chassis a proper line-following robot, coded in 6502 assembly.

[Carbon]’s video of his bot below.

The project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

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Hexbug Code Rewrite Makes It A Walking Line-follower

February 15, 2012 by Mike Szczys 3 Comments

You know you’ve got a good hardware platform if you can easily repurpose it with a code rewrite. And that’s what [Eric] continues to do with these little Hexbugs. This time around he’s bent the IR emitter and receiver downward to use as a reflectance sensor. This gives it the ability to follow a dark line on a light surface.

He originally patched an MSP430 into the $25 RC toy. The IR pair was intended for obstacle avoidance, which we saw in a recent links post. This hack does a great job of repurposing the avoidance system. Since the add-on hardware is mounted on a motorized turret, the single sensor pair can sweep back and forth to find the line it will follow. In one way this is better than most line followers which use multiple sensors mounted to the body. But the drawback is that this results in slower travel and won’t be winning any contests. Don’t miss the demo clip after the break.

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Matchbox-sized Line Following Robot

September 7, 2011 by Mike Nathan 28 Comments

pocketbot_line_following_robot

While they are not nearly as complex as their self-navigating brethren, building line following robots is no simple task, especially when they are this small. The creation of [Ondřej Staněk], this matchbox-sized line following robot is quite impressive.

PocketBot’s 48mm x 32mm circuit board also acts as its frame, supporting the wheels, motors, microcontroller and more. The brains of the operation is an ATmega8 microcontroller mounted on the bottom of the bot. A pair of wheels are driven independently using a set of mobile phone vibration motors that power the bot at speeds of up to 0.35 meters per second. Line detection is achieved by using three different IR sensors paired with four IR emitters located at the front end of the bot.

PocketBot also has an IR receiver on its top side, which allows [Ondřej] to control the robot, tweak its parameters, or calibrate its sensors on the fly using an IR remote or his computer.

The PocketBot might not be the absolute smallest line following bot we’ve seen, but it’s pretty darn close!

Continue reading to see PocketBot in action.

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Making A Line-following Toy Into A Programmable Robot

August 31, 2011 by Mike Szczys 1 Comment

[Eric Gregori] picked up this little yellow robot as a kit build. It has a single PCB inside that has a pair of IR emitters and detectors pointed downward at the front of the robot. It is able to follow a dark line on a light surface based on how the infrared beam reflects back to the detector. But it’s a one-trick pony that [Eric] wanted to make into a programmable robot.

The kit came with a schematic, which makes the process of patching into its logic quite easy. There are two motors, each with a driver circuit made up of a pair of transistors and one flyback diode. This means the motors can only move in one direction, but they also only take one logic connection to control. Instead of populating the transistor that usually connects the IR receiver to the motor driver, [Eric] soldered jumper wires from each to an MSP430 chip (the G2231 that came with his Launchpad).

As you can see in the clip after the break, the first version of the code he wrote makes the robot follow a line as it would if it had not been altered. But there’s still plenty of programming space and several free I/O pins for future improvements.

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Line Following Tank Without A Microcontroller

September 17, 2010 by Mike Szczys 23 Comments

This line following tank uses analog circuitry to sense where a dark line is and adjust its course. Despite the opening paragraph on the schematic page (which looks to be leftover from a past project writeup) this circuit relies on a set of transistors for motor control. [Chris] does a great job of explaining the setup in detail; it boils down to a phototransistor detecting reflected light and flipping which motor is running based on what is detected. A couple of potentiometers are included to tune up the accuracy of the circuit. There’s a short clip of the treaded-terror making a loop around the track after the break.

This is another great way to try your hand at analog circuitry. Once you’ve built the body (tank or otherwise) and line tracking circuit it can be repurposed by swapping out the brains for your next project.

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