Robot Project :: Circuit Explained

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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

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Originally uploaded by orangejacket05

Robot Project :: Workshop Day 3 :: Circuit Complete

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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/

Soldering

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Originally uploaded by orangejacket05

Going low-budget on the first robot means more work. I am creating bridges between components using solder and 18 AWG wire since the board has no buses. It is testing my eye-hand coordination without a doubt.

The robot brain circuitry in development

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Originally uploaded by orangejacket05

So far the circuit contains most of the headers, a 340 ohm resistor, LED, and the 18 pin DIP socket.

Robot Project :: Workshop Day 1 :: Starting from the Ground Up

A dream of mine since childhood, building a robot, always seemed like something that I would never find time to complete. Being that Short-Circuit was one of my favorite movies from the 80's as I was growing up, I guess it was inevitable that I'd want to build a robot one day.

At the ripe old age of 27, I have decided to tackle a few of the goals that I've had for years. Having a full workshop and scrap supplies available to me, I no longer have any excuses. Also I have to give credit to societyofrobots.com for their generous advice and forums for this project.

Giving engineering and science education demonstrations in local schools during graduate school has given more reasons to begin building robots. Robot demonstrations are a great opportunity to show students about engineering in a way that is entertaining and educational.

This first bot will be a differential drive robot that mostly performs object-avoidance. I am building the bot from basic components: an ATMega8 microcontroller, resistors, capacitors, servos, photoresistors, etc. I will use an external programmer to download and test various control algorithms.

Workshop day one ...

Soldering for the first time went smoothly for a while, but I eventually learned the hard way how solder wicks can save a project. Today I've finished half of the brains behind the machine; I soldered most of the headers, the 28 pin DIP connector, a resistor, and LED. Since I will be using a newer programmer, the Pololu USB AVR 6-pin ISP programmer, than some guidelines that I have been following, I reconfigured the pin layout from 10-pin to 6-pin based on the programmer module pinout diagram.

Bandsaw skills from ME2110 at my alma mater came in handy as I cut a circular CD-sized disc from a 3/8" thick polypropylene sheet. A nearby machine shop donated the PP sheet.