Robot Project :: Video of Bot Auto Steering

The bot project is sitting idle no longer - I have replaced a bad photoresistor and tuned the program to improve light detection. This video shows the photovore robot traveling around the perimeter of a wall and autosteering to prevent collision with the wall.

This photovore works by detecting incoming light to two photoresistor sensors, each positioned approximately 45 degrees on opposite sides from a line normal to the robot face. The robot will respond to one of four scenarios: (1) incoming light is approximately the same intensity at both sensors; (2 and 3) light is greater at one sensor than the other; and (4) incoming light is very low at both sensors. In case one, the bot steers straight. For cases 2 and 3, the bot will follow the direction of greater light, and for case 4, motors for both wheels stop running.

Robot Project :: Robot Completed

My first robot project is now completed. It only took a weekend afternoon to complete, but I let it lapse while focusing on my dissertation and research this fall.

The function of the robot is simple: detect light to the left and right and continually drive itself while remaining within an area having light.

I've been able to keep a low budget by finding materials for free or creating parts from what would otherwise by trash. Here's a short list of the components:
- Body: 1/4" thk. PP sheet cut to the size of a compact disc.
- Sensor body: electrical tape.
- Wheels: peanut butter jar caps and rubber bands.
- Attachment: screws (wheels) and velcro (nearly everywhere else).
- Rear stabilizer: Tenergy 2000 mAh 6V battery.

Some of the key tricks/modifications necessary:
- The Hitech HS-311 servos are made stock to only rotate 90 or 180 degrees. The servos must be disassembled and modified to permit 360 rotation; they also must be calibrated to prevent rotation when not desired.
- There were no complete instructions for creating the programmer circuit on the board for the Pololu AVR programmer. Another hobbyist provided some direction with this.
- The C-code needs to be tuned to improve the response to sensed ambient light.

Final verdict: the robot rotates the wheels to move in the correct direction when one sensor is exposed to light and the other is blinded. However, the response to areas of light and shadow in the floor of my apartment are less than the accuracy it needs to work well. This may be due to the shine off my floor or poor lighting. I'll post a video once I find a surface and lighting conditions where it works well.

Robot Project :: Circuit Explained

IMG_1735
Originally uploaded by orangejacket05

With no access to a CAD program, I have not been able to make a good sketch of the circuit diagram yet. Instead, I'll give a description of the circuit components and circuit operation.

What is the purpose of the circuit?
This circuit uses two photoresistors to detect light, read the voltage drop across the sensors, and determine automatically which servo to power using a differential drive setup, thereby steering the vehicle automatically per the user-defined embedded code. The code may be written to make the robot remain within an area, track lines, etc.

Components (from top-left to bottom-right moving down the circuit):
- 3 pin header for battery connections (behind the voltage regulator)
- 5V linear voltage regulator: provides steady voltage to the microcontroller/sensor bus.
- 220 microF capacitor: meets unsteady servo load with peaking power.
- Servo headers
- LED and resistor: circuit ON/OFF signal
- ATMega8 AVR microcontroller: circuit brains, sensor signal processing, program execution
- Sensor headers
- 6-pin programmer headers: designed for the Pololu AVR programmer.

Soldering Completed

IMG_1736
Originally uploaded by orangejacket05

Robot Project :: Workshop Day 3 :: Circuit Complete

IMG_1735
Originally uploaded by orangejacket05

I finished the circuit today and powered it up, and it passed the first tests! No sight nor smell of smoke was emitted from the components or wires.

After finishing all soldering I used a multimeter without an external power source as a first circuit test:
- no connections between the power and ground buses (risk is melting down the battery and causing sparks).
- all intended connections are functional
- no short circuits between adjacent buses
- verify that all connections around the voltage regulator are functional

For my next test, I connected a 7.5 V rechargeable battery with alligator clips to the power input headers. I test the servo power bus and the microcontroller circuit to ensure proper voltages:
- The servo bus read voltages near 7.5 V
- The sensor bus voltages were at 4.95 V
So far, so good. The voltage regulator is working as expected.

Top 10 Robots of the Past Decade

Gorobotics. net has made a list of the top 10 robots of the 2000's thus far. The list in no particular order is as follows:

- KeepOn - autism research, human interactions
- PackBot - search and investigative operations for 9/11 and Afghanistan
- Pleo - toy, human interaction, learning ability
- Big Dog - 'pack mule' for soldiers in the field
- RoboSapien - toy, hobbyists
- Asimo - Honda walking, life-sized robot
- Aibo - robot dog
- Predator Drone - reconnaisance
- LEGO Mindstorms - toy, education, hobbyists
- Roomba - vacuum

One robot that has my top vote for the next decade is the ROV used by BP to monitor and close the Deepwater Horizon oil well. Admittedly, it is not a robot in the purest sense since it is controlled by humans; however, it deserves credit for lending the vision and hands to complete much of the repair work.




For the list by gorobotics.net: http://www.gorobotics.net/articles/top-10-robots-of-the-past-10-years-robots-of-the-decade-awards/

BeatBots

The Keepon seems like a relatively simple toy, but the motivation for the robots is compelling. One of the visible human traits that robots commonly lack is the rhythm we express in communication, often seen in speech and movement. Common examples include the use of hand gestures in combination with words to convey a message, or when we express empathy by responding to others emotions in a similar manner. Synchronization between the emotions perceived by others and our responses is a critical part of human relationships and identifies characteristics about the other, and oftentimes this synchronization comes naturally as we convey our thoughts.

The Keepon has been designed to make 'eye-contact' with faces, has four degrees of rotational freedom, and has dance skills and rhythm that puts many people to shame.

One application of Beatbots have been to study autism and has demonstrated how autistic patients seek to share interest in others. In the study autistic children expressed positive emotion in response to the Keepon and then sought to communicate their positive interaction with the Keepon with an adult. The unique aspect of the Keepon for autism studies is thought to be how it relays emotional response in a simpler and more consistent manner than in human interaction. More on the autism research: http://beatbots.net/2008/09/25/the-works-robots-on-the-history-channel/