Project Jerhico

The new project has begun. It has been codenamed Project Jericho, and the plans are being finalized. The boys and I have been planning this project for almost a year. It will be a track driven (tank) robot. We plan to run it from car wiper motors and some kind of timing belt or other automotive belt with teeth.

When we decided on a tank design early on because our last project “O.F.F. R.O.A.D” gave us challenges we didn’t want to face again.  First OFF ROAD was built out of an old 4 wheeled Powerwheels chassis.  We had it running forward and back, but didn’t have the time to build in steering.  Because of this, we thought a track design because it would allow for steering by just adjusting the forward and reverse of the motors.

After the tank idea was agreed upon, I scoured the Internet for track designs.  I thought there would be all kind of options, but found that unless we wanted to make something about the size of an R/C car we would have to build our own tracks from the ground up so to speak.  I am not knocking the R/C car size robots, in fact I found some really great looking tracks for that size at Amazon.  It is just we want a robot that uses a netbook PC as the brain instead of a microcontroller.  It will become clear why we needed the power of a netbook later.

Ideas for Tank Tracks

The best site I found during my searches RC Tank Combat really got my brain thinking in tank terms.  I started looking deeply at how tracks work and how the wheels and tracks really match up to move the vehicle. It also showed me that R/C builders really understand the mechanical engineering necessary to build a custom vehicle.

At this point I was pretty set on building either the bicycle chain track or the chain and bolt track.  I was a little worried that our robot project was going to be more of a mechanical engineering learning experience than the electrical engineering project I was hoping to teach my kids with.  I have very little background in any kind of mechanical engineering and am more comfortable with electrical, so I was worried I would spend too much time learning rather than teaching.

As I was re-reading over and over the track designs at RC Tank Combat, I was also doing a lot of looking at images of real tanks in use today as well as WWI and WWII tank designs.  It was also a big help to see tracks in motion on youtube.  During days and weeks of planning and research on tracks, I came across what has turned out to be our best resource: A homemade tank on FastMHz.com. Again this was an R/C vehicle, but it was so detailed all I had to do was ignore the speed controllers and think in terms of motor controllers.  This post had all the detail I needed on not only the tracks, but the types of motors to start looking at and voltage to run.

The tracks of the FastMHz tank were made out of snowmobile drive belts.  But studying the pictures, I can probably use any kind of automotive belt with teeth.

Motors

Another big find with the FastMHz tank was it showed we could use wiper motors to drive the tracks.  What a great idea because they are strong and the gear box is built in.  I used the wiper idea to search the Internet again, and I found the site Monster Guts. This site sells equipment for building Halloween props.  Among their collection of components, they sell a wiper motor and it is only $15!  A search of ebay brought up new wiper motors in the $50 – $100 range.  I can get 2 from monster guts for less than one anywhere else.

Monster Guts Wiper Motor

More to come:

We are ready to move now.  We have a design and a sample tank to use as a reference.  We know how to build the tracks, and we know where to buy our motors.  Now it is time to think about sending power to the motors.  We are going to buy some parts, do some wiring, and take some pictures.  It should be fun and educational for the kids.  I hope it is inspirational to you.

Here is a small R/C tank chassis if that is the design you want.

Project Jericho – A Tank is Born or At Least Designed is a post from: MAD Robotics

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Finding information about servo motors and drives online can be difficult and even if you find it the language used is commonly over complicated and difficult to understand. Commonly the information is related to industrial applications. This is commonly the case in the field of motion control and servos.

Servos are crucial elements in robots but they are also components in such items as radio controlled vehicles. Servos are devices which have a shaft (a rod which can be placed at specific angles using a coded signal. By changing the coded signal the servo will alter the angle of the shaft accordingly.

Even though Servo motors are rather small they have incorporated control circuitry and they are incredibly powerful packing enormous torque. All of this power is controlled by just three wires, one for earth and the other two for power and control.

And Now For The Technical Stuff

Unfortunately I cannot avoid being a little technical here, but stay with me and you might find that you comprehend the concept.

As well as the control circuit servo motors feature a component called a potentiometer (a variable resistor) which is connected to the output shaft. The potentiometer helps the control circuit to measure the current angle of the servo.

Normally servos control angular motion up to about one hundred and eighty degrees, a few servo motors go further but to go beyond two hundred and ten degrees is near impossible and servos feature a mechanical stop which is built into the main system to prevent it.

The Servo Drive

A servo drive is used to power servo motors. By altering the electric current sent to the servo motor the drive enables proportional control. Because the level of power applied to the motor is proportional to the amount of distance it moves extremely precise movement is possible.

Servo motors are used in diverse areas of industry such as CNC machining, factory automation and robotics. Although these servos are commonly huge they can also be much smaller for using in consumer products and consumer robotics systems such as Lego Mindstorms.

If you a looking to purchase industrial servo motors, or need specialist help and advice contact Goodwin Electronics.

Servos, What Are They? is a post from: MAD Robotics

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When I got home from work today, It was sitting on my front porch. The kids were off at piano / parkour practice. I was a good dad and didn’t even open the box before they got home. When they came in, I said “our kit came!” The looks on their faces reminded me that I had never even told them I ordered it…oops.

The boys spent no time at all clearing a space on the dining room floor and grabbing the instruction book out of the box.  We did the first 2 projects in about 2 minutes.  The first project was adding a light and a switch. If you don’t have a basic understanding of electricity, take a minute to read my Introduction to Electricity post. Don’t worry, we will wait…

Ok, glad you made it back. The boys took the batteries out of their Wii Mote and as Genesis Chapter 1 tells us, “…there was light.”  I took a few minutes to recap about electrons flowing from the negative side of the batteries, through the switch and into the light bulb. Daniel (7) didn’t really care what I was saying…for heaven sakes, there was a light shining on the board. He didn’t have time to talk about electrons. Andrew (9) looked like he kind of understood the concept of the flow of electricity, and when his brother Mike (12) explained how the switch could stop the flow the switch in Andrew’s head really kicked on.

The next project involved a motor and a helicopter blade. What is cooler than that? I will tell you, a voice activated music player! Well keep your eyes out for cool projects the kids build with this thing. You would think I bought them a new toy they are so excited to mess with this kit tomorrow. This is a homeschool father’s dream.

Here are some quick pictures I took with my phone, sorry about the quality. Also, a special thanks to Mike for taking charge of reading the instructions to the little ones. You are such a great big brother.

Unboxing of the Snap Circuits Jr.

Andrew and Daniel with some Snap Circuits parts to make their first creation on their own.

Here is Andrew starting the build

Here is Daniel doing his part. Notice the piano letters on his fingers

Here is the final product of their work. The red light lights up when the clear sensor above it sees light. The flash on my camera was all it needed, the red light is on.

I took one without the flash, so you can see the red light is off.

Andrew thought he wanted a switch instead of the light sensor. It was as easy as taking the sensor out and snapping the switch in.

Snap Circuits Kits Electronics Learning as Easy as Legos is a post from: MAD Robotics

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The robot is designed to be controlled remotely and for people near it to interact with the robot like they would interact with a person.

Checkout this video from Anybots:

As I was reading their press release, I thought why stop at telecommuting? I remember when I was a kid, my brother was stuck in the hospital for a month or so. My mom had to stop by the school and get his assignments and bring them to him. If she had not done that, I am sure he would have had to repeat that grade the next year. Using something like the Anybot design, he could have not only done his assignments, but interacted with his teacher and students.

The Anybots robot costs $15,000.  That takes it out of reach for most people which is why the company is focusing on businesses. I see a market for other more inexpensive robot designs to take on the consumer market. All that needs to happen is take an inexpensive robot design, add a webcam and some type of wireless connection.

I had mention before that the kids and I are in the process of deigning our next robot as a tank. We have given it the code name Jerico.  Jerico is at the planing phase, but we already decided we wanted to be able to control is remotely from a laptop and see where it is going from a webcam.  I think we will add a feature to bring the webcam to eye level with people walking and add a speaker to interact with anyone near the robot.

Challenge

Create a robot design on paper, an drawing, or a video of something you actually made. I want to see if we can create something that does what Anybots is doing for under $1,000. Post a link to your designs in the comments.  I will get Andrew to draw up our ideas and post them too. I hope to work off everyone’s ideas and design a MAD Robotics version.

Requirements

• Webcam
• Remote control from another computer
• Sound to talk to people from the remote computer
• Ability to fit through standard door openings
• Keep the parts under $1,000

Anybots Bring the Remote Location to You is a post from: MAD Robotics

Basic complete electrical circuit

We all use electricity every day. From the moment our electric clock wakes us up in the morning until we turn the light off for bed at night. It has become so common place, that we take it for granted. I am going to discuss the various parts of an electrical circuit and what happens when you have all the pieces connected correctly.

Main Properties of Electricity

• pressure (voltage)
• current (amps)
• resistance (ohms)

Electricity begins in atoms.  These are the tiny microscopic building blocks that make up everything. We will talk about atoms in another article, but for now just bear with me.  Atoms are made up of protrons, neutrons and electrons.  It is the electrons that we are most interested in.  The process of atoms moving their electrons in a path (or circuit) is electrical current.

Voltage is the force that makes these electrons jump from atom to atom.  In a typical DC (Direct Current) circuit such as a flashlight, the voltage is created by the battery.  In the diagram, you see there is a battery which is connected to a light bulb.  The voltage from the battery is stimulating the electrons in the circuit to give up electrons.  The electrons are moving from the negative side of the battery (the black line shown with a minus “-” sign). When the electrons reach the light bulb, it converts these extra electrons to light and then passes them back to the battery through the positive line (the red line shown with a “+” sign).

Resistance slows down the flow of electrons.  We get some resistance just from the wires coming out of the battery. The smaller the wires the greater the resistance.  The main source of resistance in our example is the light bulb itself. The filament causes the flowing electrons to enter a smaller space.

Short Circuit

If we took the light bulb out of our example and connected the negative and positive wires together we would get a short circuit. The electrons would move quickly from the negative to the positive side of the battery discharging it quickly.

Competed Circuit

Basic open electrical circuit

An electrical circuit must be complete meaning that there needs to be a direct connection from both sides of the power source. If that line is severed, the circuit will not be complete and electrons will not flow. This law is why we can have switches. Think of turning on the light in your bedroom. When you flip the switch to the on position, it is completing the circuit and allowing the electrons to flow to your light.

Notice in the diagram that the negative connection was removed from the light bulb. This caused the bulb to stop shining because the electrons are no longer flowing from the battery.

This happens because unlike water electrons don’t really flow, the are attracted by atoms that are missing electrons. This is where the positive connection comes in.  The positive side of the battery is in need of elections and the negative side of the battery has extra electrons. The positive side pulls the electrons from the negative side.  Have you ever charged a dead car battery (or seen it done)? If the negative side of the jumper cables are attached and the the positive side, you usually see a spark or arch.  This is caused by the positive side of the circuit pulling so hard for electrons from the negative side that the electrons literally jump through the air to get to the other side.

Conclusion

We talked about voltage as the pressure moving electricity, current (amps) as the flow of electrons, and resistance (ohms) as the slowing of electrons in the circuit.  I also explained that a circuit needs to be complete because the positive side is pulling electrons from the negative side.

Project

Take 2 pieces of coper wire and attach them to both sides of a flash light light bulb.  Attach the other ends of the wire to both ends of a C or D battery.  See if the light bulb lights up?

Post your results in the comments!

Extra Credit

What happens if you add more batteries? Make sure you connect the positive side of each battery to the negative side of the next.

Introduction to Electricity is a post from: MAD Robotics

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Review

history and theory behind behavior-based programming… teaches skills needed for programming… test[s]… expertise… intuitive… deconstructs robot control into simple behaviors — Sci-Tech Book News, June 2004

* Teaches the concepts of behavior-based programming through text, programming examples, and a unique online simulator robot * Explains how to design new behaviors by manipulating old ones and adjusting programming * Does not assume reader familiarity with robotics or programming languages * Includes a section on designing your own behavior-based system from scratch (20040601)

See all Editorial Reviews
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Robot Programming : A Practical Guide to Behavior-Based Robotics [Paperback] is a post from: MAD Robotics

From the Manufacturer

Command the robotic arm gripper to open and close, radial wrist motion of 120°, an extensive elbow range of motion of 300°, base rotation of 270°, base motion of 180°, vertical reach of 15 inches, horizontal reach of 12.6 inches and lifting capacity of 100g. Some of the added features include a search light design on the gripper and an audible safety gear indicator is included on all 5 gear boxes to prevent potential injury or gear breakage during operation. Total command and visual manipulation using the “5′s”, five-switch wired controller, 5 motors, 5 gear boxes, and 5 joints. For ages 10 and up. Add USB Interface cable and Software, OWI-535USB, (not included) to integrate programming and expand the capabilities of the Robotic Arm Edge.

If you’ve ever seen video of those giant, articulated robotic arms in an auto assembly plant doing their thing, you know what true modern marvels they are. The speed and precision wit (more…)

OWI Robotic Arm Edge is a post from: MAD Robotics

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“I wrote this book because I love building robots. I want you to love building robots, too. It took me a while to learn about many of the tools and parts in amateur robotics. Perhaps by writing about my experiences, I can give you a head start.”—David Cook Robot Building for Beginners, Second Edition is an update of David Cook’s best-selling Robot Building for Beginners. This book continues its aim at teenagers and adults who have an avid interest in science and dream of building household explorers. No formal engineering education is assumed. The robot described and built in this book is battery powered and about the size of a lunchbox. It is autonomous. That is, it isn’t remote controlled. You’ll begin with some tools of the trade, and then work your way through prototyping, robot bodybuilding, and eventually soldering your own circuit boards. By the book’s end, you will have a solid amateur base of understanding so that you can begin creatin (more…)

Robot Building for Beginners (Technology in Action) [Paperback] is a post from: MAD Robotics

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The FIRE program is even being sponsored by DARPA (Defense Advanced Research Projects Agency) because as a nation, we are losing our strategic placement in the world when it comes to science and technology.  According to Carnegie Mellon, “The number of U.S. college graduates with CS-STEM degrees is declining, raising concerns about national competitiveness. The trend is particularly pronounced in computer science, where the number of graduates dropped 43 percent from 2004 to 2007 and where women and minorities remain underrepresented.”

FIRE is developing new tools that help middle and high school students to expand their interest in robots, leading them from one Computer Science activity to the next. Examples are programming tools that create game-like virtual worlds where robot programs can be tested, as well as computerized tutors that teach mathematics and computer science in the context of robotics.

For more information on the FIRE project visit: www.fire.cs.cmu.edu.

Fostering Innovation through Robotics Exploration is a post from: MAD Robotics

I tried starting with Visual Basic.  It was my first programming language so I thought it would be a good start.  Showing Mike around forms and controls was easy enough.  He could see things like a button and move it around the form.  He knew what a button was and that clicking on a button did “stuff”.  That is where the problems started.  Once you have a button on the form, you have to write code to make it do that magical stuff.  Writing code is hard to explain to an adult, I found it even harder to explain to a kid who just learned how to read.

Talking about things he could not touch, let alone see just went right over his head.  He got frustrated and I got discouraged, so we stopped trying.  Years later it hit me, lets make a robot.  He could see the product of that and hopefully learn some programming along the way.  My problem was that I knew nothing about robots.

I started searching the Internet for everything I could learn about robots and how to build them.  I look first at robotic kits and robotic toys, but it seemed like cheating.  Boy, if i knew then what I know now I would defiantly have started with a kit.  Something like Lego Mindstorm is exactly what we needed.  Anyway, I started looking at microcontrollers.  These are the tiny little brains that make robots more than a pile of plastic and metal that just sits like a statue.

I found Basic Stamps from Parallax.  They have kits and sensors and motors and controllers and everything I could possibly need.  The best part is that you program them in a version of Basic.  I at the time had been writing Visual Basic for 8 years, so it was a perfect fit.  I bought a Board or Education kit which came with a great book with sample projects, all kinds of sensors, led lights, servos and more.  The whole kit was designed for educators to teach with.  It really was perfect.

I worked on all kinds of sample projects trying to learn enough to teach the kids.  I still struggled with showing them the actual source code because they just did not understand variables and loops and all those boring things that go into writing code.  I then moved to the next phase, forget about code lets learn electricity.

I took them outside and we tore apart an old Power Wheels car that they never used. I got to the drive motors, stripped back the wires and brought out a car battery.  I quickly explained the basics of electricity: Power, Load and Ground.  Then I put the wires from the motor on the battery terminals and the wheel started spinning.  They were having so much fun.  Each took turns putting the ground wire on and taking it off.

I then had to research how you go from a microcontroller and board that use a 9 volt battery to a 12 volt motor.  I found that motor-controllers  are the answer. They take a small voltage single from the microcontroller and using a secondary power source (in my case a car battery) send the higher 12v power to the motor.  The really cool thing is that a motor-controller can also send the voltage the other direction.  Power to the ground side and ground to the power side and move the motor backwards.

My next step was buying a HB-25 motor controller from Parallax and writing code so the microcontroller would spin the motor forward for a few seconds, slow to a stop, spin the motor backwards a few second and stop.

We then put the car battery, motor controller and microcontroller setup in the car.  I turned put the battery in the board and off went the car.  Forward, backward and stop. We had done it, we made a real robot.  Granted all it did was go forwar, backward and stop but it was real.  Give it power and it did what we had told it to do.

The boys came up with all kinds of ideas for it, but other things took priority and we never continued on the project.  It has been a few years, but the desire is back in all of us.  We have some new ideas for new projects and have found all kinds of new components.  Stay tuned for all the excitement.

Update 8/1/2010
I think I finally have Mikey interested in learning to program C#. We sat together for about 2 hours and he wrote his first application. All it did was add 2 numbers and write it to the screen. I was so proud of him, but it really excited me a few hours later when his friend came over. He was explaining to her what he learned, and then he changed the code to add numbers with decimals instead of the whole numbers that it was doing.

Robots Kids and Homeschooling is a post from: MAD Robotics