In devices such as ignition modules found in cars, DVD players, or even state of the art desktop computers, all have devices called “EEPROM’s (Electronic Erasable Programmable Read Only Memory). These are devices that hold a program (using Assembly Language) to control various input/output pins. EEPROM’s allow devices to be controlled with as few electronic parts as possible to make a circuit smaller. If you required a timer to control a circuit, you would need many parts to control the timer and time rate, but if you used EEPROM’s, you could program a timing circuit in the chip without all the unnecessary parts. EEPROM’s also protect a company’s work from competing businesses that will buy a competitor’s products for simply disassembling and circuit tracing. The more programmable EEPROM’s, and the less bulk parts a product has, the smaller the final results are. Never the less, it is harder to clone a compatible product without the complete source code stored on the chip.

When we look at the Basic Stamp, which is found on our robot, the stamp is actually an EEPROM with PBASIC to ASM language converters. The Basic Stamp on robot and the one used to transmit/receive a wireless signal to the robot hold programs to control the I/O pins. These I/O pins (on both stamps, BS2 and BS2P40) control the signal transceivers, sonar modules, IROD’s (infrared object detectors), high current motor direction controlling H-Bridge, and a serial LCD status screen (can be found only on the BS2P40).

            The sonar sensors that are located on our robot demonstrate how echolocation and object detection can be used to guide automatic devices. We all know how bats find there way around objects at night so they do not crash into things when they fly around. Some people even know how fish finders can find the big fish you want to try and catch. They both use two things; sound and judgment, which is the same thing our robot uses. The Basic Stamp (located on the robot) tells the sonar modules to send a pulse of a sound at approximately 40,000 Hz (40 kHz) out into the open. If an object is in the way, the sound will hit the object, reflect back towards to the sensor where it detects the high frequency sound, and tells the Basic Stamp that it received a high frequency pulse. The stored program inside the BS2P40 stamp uses math to calculate the time from when a pulse was sent, till the pulse was received. This formula is, (((P_{f (1)}  – P_{i (1)}) + (P_{f (2)}  – P_{i (2)}) + … + (P_{f (n)}  – P_{i (n)}))  / A) / K = D where:

·        P_i = Pulse initial - Time taken before the pulse was transmitted

·        P_f = Pulse final – Time taken after the pulse was received

·        A = Pulse average – Average for number of pulses made

·        K = Constant – Constant used to convert raw time to a distance measurement (K = 73.476 for standard (inches), K = 23.033 for metric (cm))

·        D = Distance – Total distance calculated

The IROD sensors (infrared object detectors) are indeed far simpler then the sonar sensors are. The IRODs work by emitting a constant stream of infrared light, if or when an object is in the way, the light gets reflected back to the sensor where an infrared detector can complete a circuit by activating an internal switch. These IRODs can detect almost any object within a short range no matter what color the obstacle is. The IROD is designed to see any object, because the IROD looks for one color; gray. They are placed in a V formation so that you can turn two sensors into three.  When an object is detected it lets the stamp know when the IROD is switched low.

The H-Bridge circuitry (half bridge), are actually motor controllers. The main purpose of this motor controller is to simply turn the motors on, and control the direction either forward or backward. The two circuit boards that have the 2N6287 (PNP) and 2N6284 (NPN) Darlington transistors control the state and direction of the driving motors. This is one of the areas we encountered problems.  At one time it was hard to figure out how to control the Darlington transistors. Also, the previous circuit board that was designed to run both Darlington transistors had a design flaw; the base and the emitter were switched backwards. Later, from that point, the power supply circuit and the logic controller were designed. Again, this is where problems occurred.  It was tricky to wire up the transparent latch (74LS75) when a 14-pin socket was in place where a 16-pin socket was designed to be. This circuit resembles an industrial motor controlling unit because the 2N6287 and 2N6284 Darlington transistors are designed to run at a range of 5 to 100 volts (absolute max) from 500 milliamps to 20 amps (absolute max) D.C. This circuit will latterly run two high-powered industrial motors all from one computer, basic stamp, or any automated device. Not only can the H-Bridge circuit run robotic driving motors but it can run any high powered motor (considering the motor is not pulling power beyond the levels in which the circuit board was rated for) for any purpose.

Some of the most impressive devices used in the robot are the wireless transceivers. These transceivers can be used to control and/or monitor any device. In this case, the transceivers send a status report of the sensors and motor sequences from the robot to the computer. Also, the transceivers control the robot from remote so that it can be shut off remotely for safety purposes.

The Basic Stamp 2P40 has ‘semi-intelligence’; it can control the status of the sensors and motors that gets forwarded to the computer. The computer acts as the ‘machine-to-user interface’’; the user can observe what the robot observes, and set restrictions to notify the robot what it can and cannot do. The transceivers actually transmit and receive digital numbers rather then physically acting as a switch. The programs inside the BS2 and BS2P40 actually send and receive data at approximately 2400 bits per second as raw cashed data, not as compressed data that computer modem’s use. Commands such as SERIN (serial in) and SEROUT (serial out) are used to digitally send bi-directional binary signals from stamp to stamp.  Sending cashed data at 2400 bits per second can be pretty fast, but there are disadvantages to doing this. When sending and receiving raw data wirelessly, magnetic interference can obscure data between the two transceivers, thereby causing the robot to report false data back to the user interface. Simply slowing down the data traffic speed, and/or reporting back packets of data that can confirm the sent readings so the outcome can be corrected, can solve a lot of these problems.

             Machines like our project that can digitally forward communication, have unlimited engineering possibilities. Defusing illegal explosives, trying to talk to a criminal without risking a human life, finding earthquake victims, mining resources without using people, mapping locations where it is unsafe for people to be by reporting back the trajectory and findings, are just some of the possibilities for making our way of life safer and productive. As we move on through the new century, we will be exposed to more and more devices that are controlled by artificial intelligence. Right now there is artificial intelligence being developed that will continue to improve our way of life.