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Digital Compass

myblack60impala — Sun, 07 Dec 2008 11:42:29 CST

Devantec R117- electronic compass

This compass module was designed specifically for robotics applications for use in navigation. It works by providing a unique number to represent the direction the robot is facing. The compass uses 2 Phillips KMZ51 magnetic field sensors mounted at right angles to each other, to computer the direction of the horizontal component of Earth's magnetic field.

Connections:

Readings:

There are 2 ways to get a reading from the unit. A PWM signal is available on pin 4, or an I2C interface on pins 2,3. The PWM signal is a variable pulse width, with the positive width of the pulse representing the angle. The I2C communication protocol is the same as popular EEPROM's. First send a start bit, the module's address is 0XC0 with the read/write bit low, then the register number you wish to read. Follow this with a repeated start bit again with the read/write bit high 0XC1. You now read one or two bytes for 8bit or 16bit registers. 16 bit registers are read high byte first. The compass has a 16 byte array of registers, some of which double up as 16 bit registers.
Register 0 is the software revision number. Register 1 is the bearing converted to a 0 - 255 value. This might be easier for some applications than using the 0 - 360 values, which would require 2 bytes. Those wanting higher resolution, registers 2, 3 (high byte first) are a 16 bit unsigned integer in the range 0 - 3599. This represents 0 - 359.9 degree's. Registers 4 to 11 are internal test registers, and 12 - 14 are unused. Register 15 is used to calibrate the compass.

Vision (camera based)

myblack60impala — Sun, 07 Dec 2008 11:41:29 CST

Touch (mechanical)

myblack60impala — Sun, 07 Dec 2008 11:39:06 CST

IR (infra-red)

myblack60impala — Sat, 06 Dec 2008 17:59:47 CST

Sharp GP2D12
Distance Measuring Sensor

Infrared distance measuring sensor. Accurately determines range to target between 10cm and 80cm. Can be used as a proximity detector to detect objects between 0cm and 130cm.

Connections:

Pin 1 - Signal
Pin 2 - GND
Pin 3 - VCC

Range Sensing Operation:

The sensor works by reflected IR light from the emitting led being bounced back to the receiving sensor. The amount of reflected light outputs an analog voltage between 0-5v.
In order to use this type of sensor. Setup the sensor to read a fixed distance measurement. Then measure the output voltage at this static range. This will allow you to calculate the distance to voltage scale for the operational range of this sensor.

Ultrasonic

myblack60impala — Sat, 06 Dec 2008 17:31:10 CST

Devantech SRF04 Ultrasonic Range Sensor

The sensor provides a ranged reading from 3cm to 3 meters. It works by transmitting a pulse of sound outside the range of human hearing. This pulse travels at the speed of sound (roughly .9 ft/msec) away from the sensor in a cone shape. The sound reflects back to the sensor from any objects within its path.
The controller requests a ping, the sensor creates the sound pulse, and waits for a echo return. If received, the sensor reports this echo to the controller, and the controller can then compute the distance to the object based on the elapsed time. The beam width of the pulse cone is roughly 30 degree's.

Connections:

Timing:

There are a couple requirements for the trigger and output pulse generated by the sensor. The input line should be held low 0v and then brought high 5v for a minimum of 10 microseconds to initiate the sonic pulse. The pulse is generated on the falling edge of this input trigger. The sensors receive circuitry is held in a short blanking interval of 100 microseconds to avoid noise from the initial ping, then is enabled to listen for the echo. The echo line is held low until the receive circuitry is enabled,. Once the receive circuitry is enabled, the falling edge of the echo line signals either an echo detection, or the time out if no object is detected. Your controller will want to begin timing on the falling edge of the trigger input and end timing on the falling edge of the echo line. This duration determines the distance to the first object the echo is received from. If no object is detected, the echo pulse will time out and return an echo at approximately 36 msec.

Logo

myblack60impala — Sat, 30 Aug 2008 12:35:49 CDT

Logo is a graphical programming language that was developed by a team from MIT.
It was originally designed to introduce children to programming concepts. Its intended design was to be easy to learn, easy to use, easy to read, and powerful enough to cope with complex problems. While mirroring the Basic programming language in order to make the progression to a higher text based language easier.

Over the years it has developed into one of the widest used robotics programming languages ever created. Logo is the base programming language that was modified for use with the popular Lego Robotics kits. (The image to the right shows the stock form of Logo.)

While most users typically advance beyond Logo's simplified programming interface to higher programming languages. Its compiler does use Basic, C, or Assembly language behind the graphical icons (depending on the version). And most versions also allow users the option to program in these text based languages.

Today Logo users have a wide variety of micro controller options for their projects. From the Lego RCX/NXT kits, to the Inex RoboBox kits, or the Gleason Research Cricket series of controllers. The industry has also developed Logo interpreters for all the popular brands of microprocessors used today.

BASIC

myblack60impala — Sat, 30 Aug 2008 12:31:29 CDT

BASIC (standing for Beginner's All Purpose Symbolic Instruction Code) is a system developed at Dartmouth College in 1964. It was meant to be a very simple language to learn and be easy to translate to spoken language. Additionally, the designers intended it to be a stepping-stone for students to learn more powerful languages such as FORTRAN or ALGOL. (Which were main stays of this early time in the evolution of computing.)

Over the years its evolved to be a main stay programming language for everything from computer applications to robotics programming.

(under construction)

Examples:

MS Visual Basic
Bascom Basic
Chipmunk Basic

LED

Winfieldmike — Mon, 25 Aug 2008 09:51:10 CDT

LED stands for light emitting diode, and can be found in nearly every electronic device. It's almost a law that every robotics project must have at least one "blinking light".

LED's are usually low voltage devices, and come in numerous shapes and sizes from tiny surface mounted ones the size of a grain of rice to monster 5 watt ones that can light a room. When supplied with the correct voltage and current, LED's can last many thousands of hours of continuous use.

A standard LED has two leads, with one usually shorter than the other. The short lead is called the cathode, and is usually further identified by a flat spot on the plastic housing of the LED. Polarity (hooking up the + and - leads correctly) is extremely important. Just a moment of voltage applied incorrectly can destroy the LED. It is common to have a current limiting resistor in your circuit to prevent too much current from being applied to the LED. Here is a link to a handy on line calculator to help design your LED circuit.

Components

Winfieldmike — Mon, 25 Aug 2008 09:18:33 CDT

This section contains information on the components that make up your circuits...resistors, leds, capacitors, semiconductor chips, transistors, etc.

Freescale

myblack60impala — Sat, 23 Aug 2008 18:44:53 CDT

There is no abstract available for this page revision.

ROBOMO WIKI Home

Winfieldmike — Sat, 23 Aug 2008 03:08:01 CDT

Welcome to the ROBOMO Wiki, an extension of the ROBOMO club website. Please visit our main website at http://www.robomo.com for information on upcoming meetings and to access our active forum.

Set up the Arduino

Winfieldmike — Fri, 22 Aug 2008 13:59:23 CDT

The Arduino is an ATMEL Mega168 base microcontroller board. See the ROBOMO wiki entry here for additional info.

The Arduino can be connected to your computer in three ways:

9 pin serial port. Many newer PC's and laptops do not have a serial port, however a good name brand USB to serial converter will work. We have confirmed sucess with Keyspan brand adaptors. The advantage to using a 9 pin serial Arduino is cost...$17 for serial as opposed to $34 for USB.
USB. All PC's and laptops come with USB ports. A USB Arduino has the advantage of being able to be powered through the USB port with no external "power brick" required. This makes it easy to program up your Arduino while sitting in your favorite easy chair, and then move it to battery power once you install the Arduino in your robot.
Bluetooth. Requires no physical connection from the PC to the Arduino. Programmed with a Bluetooth low powered radio. Bluetooth Arduinos also have the ability to receive commands from Bluetooth devices such as your cell phone. Bluetooth Arduinos are the most expensive version at $150.

Download and install the Arduino software.

Download and install the Arduino software. The Arduino software is available for Linux, MacOS X, and Windows.
Linux downloads are available here. If you use Ubuntu, specific instructions are here.
MacOS X downloads are available here.
Windows downloads are available here.
Install the software like you normally would. Once installed, make sure it starts without any errors.

Connect the Arduino to your PC. For the purposes of this example, we will be connecting the 9 pin serial Arduino to our PC. (connecting the USB Arduino is much simpler...just plug and play!)

Start by connecting the Arduino's 9 pin serial cable from your PC to the Arduino. Screw down the connectors for a nice tight fit.
Plug the "power brick" into the wall, and then into the power connection on the Arduino. All Arduino's have a power LED, so it should be on now. Note: once the Arduino is powered up any programmed stored in it's memory will begin to run. There is no "go" switch. Ensure that any motors are either physically disconnected or in a safe condition should they turn on unexpectedly.
Run the Arduino software that you installed earlier.
When the Arduino sotware starts it should detect the Arduino board and select the correct port (serial, USB, etc.)

You are now ready to begin loading programs into the Arduino. Maybe give some of the more basic example programs a try. Look in the examples section in the menu and try out the blinking LED program. Remember, the Arduino environment does everything...you write and edit your program, compile it, and upload it to the Arduino all within the Arduino environment. Nice and easy! Join the Arduino forum for a wealth of further information. The Arduino people are friendly and extremely helpful.

Circuit schematics

Winfieldmike — Fri, 22 Aug 2008 13:55:43 CDT

Circuit schematics are the heart of any robotics or electronics project. Beginners may want to use these schematics exactly as described, while those who are more advanced may wish to modify and expand upon them.

A schematic is really just your roadmap or blueprint in building a complete project. Use the exact componts listed in the schematic if you want it to work as described...even though there is usually some "fudge factor" in the values of components, until you gain more experience just go with what is called for. Of course once the circuit is working, experiment a bit. Don't let the smoke out or it won't work any more! :)

A sample schematic:

C

Winfieldmike — Fri, 22 Aug 2008 13:38:03 CDT

(give a brief history of C, advantages, code samples, links to compilers, etc.)

LEGO

Winfieldmike — Fri, 22 Aug 2008 13:36:36 CDT

(explain what the LEGO system is, different types, links)

PIC

Winfieldmike — Fri, 22 Aug 2008 13:36:03 CDT

(explain what the PIC is, different types, links)

ATMEL AVR

Winfieldmike — Fri, 22 Aug 2008 13:35:36 CDT

(explain what the ATMEL is, different types, links)

Arduino

Winfieldmike — Fri, 22 Aug 2008 13:23:13 CDT

The Arduino is a microprocessor board that uses the Atmel Mega168 (older versions used the Atmel Mega8). The controller board features input/output pins, the ability to use battery or wall adapter power, and can be programmed via 9 pin serial, USB, or bluetooth, depending on the hardware version.

The main Arduino website: http://www.arduino.cc

The Arduino is programmed in C via an integrated programming environment that includes the program editor, the compiler, and the programmer. The Arduino programming environment runs on Linux, MacOS X, and Windows.

The Arduino is an open source project, and the programming environment, schematics, bootloader, and source code are freely available to anyone. Unlike other programming environments that charge hefty fees for programming environments, or give away "lite" versions that are limited in capabilities, Arduino software can be downloaded by anyone and used for free. This makes the Arduino uniquely suited for beginners or those on a budget. A 9 pin serial version of the Arduino can be purchased for less than $20.

Purchase an Arduinio USB board from Zagros Robotics. ($34.95) This Arduino board uses a standard USB connector for both programming and power to the board. When you install the board in your robot, it uses battery power.
Purchase a Bluetooth board from Zagros Robotics. ($145.95) This Arduino board uses a Bluetooth connection for programming. A Bluetooth adaptor installed on your PC is required for programming. This board will allow you to control your robot with a Bluetooth device such as a cell phone.
Purchase a 9 pin serial board from NKC Electronics. ($16.99) This Arduino board uses a 9 pin serial connection for programming, and is a good choice for beginners. If things go horribly wrong and you blow it up, you are not out a whole lot of money! Your PC may not have a 9 pin serial connection...a lot of new PC's don't. In that case, give a USB to Serial adaptor a try. I use this one from Keyspan, and it works like a champ on my Ubuntu box, so the chances of it working for MacOS X or Windows are nearly 100%.

Once you have purchased an Arduino board, see the ROBOMO wiki how to on getting it connected to your PC.

Below is an example of the typical "hello world" program, which blinks an LED. This screenshot shows the simplicity of the programming environment.

How to...

Winfieldmike — Fri, 22 Aug 2008 12:30:15 CDT

This section is for robotics and electronics how tos...how to program a microcontroller, how to determine the amp draw of a motor, how to adjust IR sensors for best performance, and anything else we find useful in building our robotics and electronics projects.

Motors/Steppers/Servos

Winfieldmike — Fri, 22 Aug 2008 12:25:37 CDT

There is no abstract available for this page revision.