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All of the procedures take a discrete ``gear'' to specify the speed. The reasons for this are two-fold; first, by limiting the power of the truck, we simplify the interface to children. Secondly, it allows use to calibrate the ``gears'' so that, for example, 10 seconds forward in first gear is the same distance as 10 seconds backward in first gear.

The limitation of LOGO however is the lack of feedback from the environment. There is no way of expressing an event occuring in the outside world.

Simple constructs in iLogo extend the original LOGO language with interactivity capabilities of reading sensors and transfering control to different parts of the program.

I wanted to share an adaptation of the Schead v4, that I have been experimenting with. It is (for lack of a better term) a Master/Slave Schmitt Comparitor Head (M/S SC-H). With the addition of a 74 AC 240 or two (as motor drivers) and a pair of motors, you can put together an interesting little light seeking, wheeled robot with peripheral vision.

As long as the light reaching the photo-bridge of the Master SC-H is balanced, then the Slave SC-H acts as a regular, lone SC-H would. So, if one of the slave photo-diodes detects more light then the other, the inverter that controls the motor on that side changes states and is now the same as the inverter of the Master SC-H tied to the same motor. This turns that motor off and the robot will pivot around the stopped wheel toward the greater light source until the light on each sensors is balanced and the motor again begins to turn.

I am also using SCar to continue experimenting with Stacking separate Sensor/Behavior circuits onto a robot. I will post more as progress is made.

All Cricket devices have a built-in bidirectional infrared communications channel, which is used for Cricket-to-desktop communication (when downloading programs to a Cricket, or viewing sensor data) and Cricket-to-Cricket communication.

Cricket Logo is based on an iterative, interactive model of project development. It includes a “command center” window; instructions typed into this window are instantaneously compiled, downloaded to a Cricket, and executed, giving the system the flavor of an interpreted software environment such as LISP, BASIC, or FORTH.

The MetaCricket software system is based on a virtual machine, written in PIC assembly language and running on the Cricket, and a compiler for the virtual machine running on a desktop development computer

CALEB CHUNG: Of course we could have used micro-servo motors to accomplish the motion of Pleo, but we aren’t able to use expensive motors. So we had to engineer it with a high-speed motor with high gearing and no backlash for control purposes and have it all fit within the muscle envelope of Pleo.

So what we did was go after a lot of ethology research. How do animals really handle the complexity of their environment? We built a virtual brain—a whole system that decides how Pleo will react in various situations.

CALEB CHUNG: Pleo will reset thresholds and adjust his idea of what he thinks is normal. Let’s say you get Pleo and you take him home to your shag carpet. When Pleo walks, the carpet will drag on his feet. So his force feedback sensors will realize that he is spending too much energy to walk around. Pleo will try different things to reduce the energy spent. Eventually, he will have the idea to step higher. Your Pleo compared to my Pleo will walk with a higher step.

The Sharp IR Range Finder works by the process of triangulation. A pulse of light (wavelength range of 850nm +/-70nm) is emitted and then reflected back (or not reflected at all). When the light returns it comes back at an angle that is dependent on the distance of the reflecting object. Triangulation works by detecting this reflected beam angle - by knowing the angle, distance can then be determined.

The IR range finder reciever has a special precision lens that transmits the reflected light onto an enclosed linear CCD array based on the triangulation angle.

The Sharp IR has a non-linear output. This means that as the distance increases linearly (by set increments), the analog output increases/decreases non-linearly.

This simple circuit can detect the invisible fields of voltage which surround all electrified objects

1381s are CMOS voltage-controlled triggers -- these "gate" a source until the voltage is above some "trip" limit, at which point it is allowed onto a third pin

We use them as 3- or 5-volt triggers

This chip is often considered the heart of Nv net technology

It is powered with two 3.3F Goldcaps. They can be charged in a few seconds. When they are charged, MAXIBUg gets "afraid" of light, and wanders of to go to play "in the dark". After a while, about 20 seconds (depending on the current used by the two motors ), the power has dropped, and it wants to "eat". It gets light attracted, and will turn and go to the light. When it gets there, it will recharge and still will be atrackted to the light until it reaches a trigger voltage , at which it gets "afraid"of the light again. This will go on all day until someone turns off the lightsource. While doing all this it also will backup when bumping into something.

Because of the "on-off" output of the first schmitt trigger, the inputs for the LDRs will switch. That's why it gets light atracted -light afraid. This also means that you cannot use IR diodes (like SHF205). You have to use LDRs !

The robots do not build a model of their world they simply act in response to the things they encounter whilst existing there.

This form of robotics has proved to be successful in environments that are unknown to the robot, environments that are busy or noisy such as a place with moving objects or people

An important part of the behaviour based theory is "embodiment" This means that a robot must be embodied, have a presence (it is an entity in itself).  In order to react the robot must be surrounded by the real world.

This book provides far more detail on the hardware aspects of robot building than any other I have seen to date and is worth picking up.

"Intermediate Robot Building" offers the kind of real-world knowledge that only an experienced robot builder can offer--the kind of knowledge beginners usually have to learn through mistakes. In this book, you'll learn the value of a robot heartbeat and the purpose of the wavy lines in photocells.

pseudocode: read left_photoresistor read right_photoresistor if left_photoresistor detects more light than right_photoresistor then turn robot left if right_photoresistor detects more light than left_photoresistor then turn robot right if right_photoresistor detects about the same as left_photoresistor then robot goes straight loop

Photovore Algorithm, Improved This algorithm does the same as the original, but instead of case-based it works under a more advanced Fuzzy Logic control algorithm. Your robot will no longer just have the three modes of turn left, turn right, and go forward. Instead will have commands like 'turn left by 10 degrees' or 'turn right really fast', and with no additional lines of code! pseudocode: read left_photoresistor read right_photoresistor left_motor = (left_photoresistor - right_photoresistor) * arbitrary_constant right_motor = (right_photoresistor - left_photoresistor) * arbitrary_constant loop

attach your Pager Motors to your Popper using two Fuse Clips, two Small Paper Clips, and no solder

The purpose of a solar engine is to act like a power "savings account" -- a small trickle of incoming energy is saved up until a useable amount is stored

A solar-powered robot can be made to work, even in relatively-low light levels

Solar cell size is minimized

These bots are powered by a Gold Cap and for a period of about one minute they move, always looking for the brightest lightspot, so in fact they will even follow a lightsource.

All these bots are powered by a 3,3F Gold Cap ( F= farad). You can charge them with a regulated power supply

the two 5 mm red LED's it is capable of following a light source.