"Exposing a Flaw: Shoot-Through" describes the serious problem
with that circuit, especially when pulsed
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How to become Data Scientist in 2019? | edWisor - 0 views
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marketngedwisor on 03 Aug 19Are you starting for your career as a data scientist? To become an expert in data science you need to begin from the ground up. And you need to get a step-by-step guide to becoming a data scientist and for learning a particular skill. Instead of jumping for a master program in computer science you need to focus mathematics, python,r-programming or statistics or develop a skill in data science. If you are looking out for such a learning institute then you could also take a walk for edwisor.com as it works for enrolled students in data science career program as well as in the hiring process and gets 4 Guaranteed interviews at top organizations.
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Robot Room - IRB and Roundabout Resourcess - 0 views
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Above is an improved version of the circuit, which is now PWM compatible. PWM, coast mode, and the capability to avoid shoot-through are provided by adding a fifth MOSFET (labeled Q5) to the source/ground connections of Q1 and Q3.
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By default at power-up, the circuit is in coast mode. To brake, set IN A to 0 V, IN B to 0 V, and Q5 to 5 V. To spin clockwise, set IN A to 5 V, IN B to 0 V, and Q5 to 5 V. To spin counterclockwise, set IN A to 0 V, IN B to 5 V, and Q5 to 5 V. At any time you can return to coast by applying 0 V to Q5. Or, you can apply pulses of 0 V/5 V/0 V/5 V (and so on) to control the speed. The more time spent at 5 V, the faster the motor will spin. Whenever you change modes, if you set Q5 to 0 V before making changes to IN A and IN B (and then set Q5 back to 5 V or pulsing) there will be no shoot-through.
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MetaCricket: A designer's kit for making computational devices - 0 views
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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.
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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.
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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
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It is straightforward to implement an interpreter-like interface, where user commands are transparently compiled, downloaded, and executed.
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Built-in infrared communications routines include a protocol for reading and writing to this external EEPROM, and for asking the virtual machine to begin execution of byte codes already loaded into the EEPROM.
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Users write programs for the Cricket in Cricket Logo, a dialect of Logo specialized for the Cricket virtual machine. Essentially, there is a one-to-one mapping between statements in Cricket Logo and primitive functions built into the virtual machine. This makes the implementation of the compiler far simpler than typical compilers.
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The compiler includes an interactive mode—a text window where user expressions are compiled, downloaded, and executed in one step when the user presses the return key. A portion of the Cricket's memory is set aside for these dynamic programs.
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we have found that a debugger is not necessary because of the interactive and incremental style of project development that occurs when using the Cricket.
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The infrared protocol includes the following capabilities: Check that a Cricket is present and ready for other commands. Write a byte to the Cricket's EEPROM. Read a byte from the Cricket's memory. Begin program execution from a particular memory address.
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User-level primitive functions compile to one, two, or three bytes of object code for the Cricket virtual machine.
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The Cricket virtual machine has two process threads: a foreground process and a background daemon. In most Cricket programs, the foreground thread handles all the work, but for some tasks, the background daemon is valuable. For example, the background daemon can be used to instigate a periodic activity, or take action when some event occurs.
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There are hardware-specific primitives for interacting with on-board Cricket hardware. Motor commands set state (on or off), direction, and power levels for each of the two integrated motor drivers. Analog sensor primitives (sensora and sensorb) return a value (0 to 255) for each of the two voltage inputs. These inputs also may be interpreted as digital values using the switcha and switchb primitives. There is a pair of primitive functions for generating tones on the piezo beeper: beep and note, the latter taking pitch and duration arguments.
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One foreground thread plus one background daemon Daemon fires when provided Boolean expression makes false-to-true transition
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RoboLogo - Teaching Children how to program Interactive Robots - 0 views
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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.
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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.
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Simple constructs in iLogo extend the original LOGO language with interactivity capabilities of reading sensors and transfering control to different parts of the program.
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These above rules handle all of the commands and expressions of the iLogo language except for the DoUnlessCommand. This command will execute a list of commands unless a boolean condition is met. If so, control is switched to a new list of commands for handling the exception condition.
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Each stage of the compiler is designed using the Visitor pattern described in the book Design Pattern by Eric Gamma, et al. This pattern allows tree traversers to be created as seperated objects, instead of doing all traversals as methods of the nodes of the tree
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We decided to use the JavaCC/JJTree tools created by Sun for generating a custom parser for our iLogo language written in Java.
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The language must have primitives which allow the user of the language to write programs which easily transfer control based upon outside stimuli, in this case sensors on the truck.
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An LM18293 push-pull motor driver connects the programmable counter array (PCA) of the 8051 to the truck's motors.
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We took the Berkeley Logo language design as our base and then added a primitive for reading sensor and an exception-based control structure.
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shared by York Jong on 27 May 07
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BEAM Pieces -- Integrated circuits - 0 views
library.solarbotics.net/...parts_elect_ic.html
5star beam collection electronics ic motor robot solar survey
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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
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The '240 is often called "the bicore chip," because we can take advantage of the 240's inverters to turn a single 74*240 into a bicore
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The '240 also has tri-state outputs, so an enable line can be used to turn its outputs on and off simply (good for adding reversing capability to a 'bot).
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any *cores built with a 74*04 will require additional logic "downstream" to amplify the current to levels sufficient to drive a moto
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74HC/HCTxx non-buffers (74HC14 or 74HC04) draw about half of the current consumption, and have about half the drive current compared to HC / HCT buffer chips (74HC240 or 74HC245). Non-buffer chips are thus better for oscillators, say Nv and Nu applications; they are not suited for use in driving motors.
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The '245 is an octal buffer chip, and so has 8 channels of buffering power available for our misuse. This chip was designed for data transmission uses, but we'll misuse it as a motor driver chip
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The '244 provides us with 8 (thus the "octal") buffers, enableable in banks of 4. This is a very useful chip for amplifying small currents
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it can drive up to 4 motors in 2 directions each, or you can "buddy up" inputs and outputs to drive fewer motors at higher current
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it can drive up to 4 motors in 2 directions each, or you can "buddy up" inputs and outputs to drive fewer motors at higher current
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If you can't find 1381s locally, you might have better luck finding its European cousin, the TC-54 -- for details on it
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Note that if you need more than about 200 mA per motor, you'll need to use an H-bridge, or some similar motor driver
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The ideal BEAM circuit would use a low (2V-3V) voltage core and sensors combined with level shifting high (5-6V) volt motor drivers to maximize efficiency.
[News] Superbot:可任意變形的模組化機器人 - 47 views
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Techmetics - Room Service Robots | robots in casino | robots in hotel USA - 0 views
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MSH 11-62 Supernova Remnant - 0 views
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Chandra of the supernova remnant MSH 11-62 reveals an irregular shell of hot gas, shown in red, surrounding an extended nebula of high energy X-rays, shown in blue.
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Chandra of the supernova remnant MSH 11-62 reveals an irregular shell of hot gas, shown in red, surrounding an extended nebula of high energy X-rays, shown in blue.
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shared by Astro Biology on 11 Nov 14
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How Massive Geographic Change may have Triggered Explosion of Animal Life - 0 views
www.astrobio.net/...riggered-explosion-animal-life
Cambrian explosion animal life earth atmosphere geological sciencce
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Scientist are researching about geologic history that may help to solve the riddle of the "Cambrian explosion," the rapid diversification of animal life in the fossil record. Learn more about what Cambrian explosion is and how it has affected animal's life in the past.
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Scientist are researching about geologic history that may help to solve the riddle of the "Cambrian explosion," the rapid diversification of animal life in the fossil record. Learn more about what Cambrian explosion is and how it has affected animal's life in the past.
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Reduce Motor Noise - 0 views
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This is the 3 capacitor method. I used this one in all my RC cars and many of the RC toys that I have taken apart use this method.
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One of the easiest and most overlooked technique that can be done to lower motor noise is the twist your motor and motor power wires. This in affect forces the magnetic fields to cancel each other out.
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By placing a metal shield between your motors and radio can do wonders. Also keep in mind that some metals shield better than others. Carbon Steel shields several hundred times better than aluminum. Dont use this shielding as a conductor or you may compound the problem.
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Place your high current wires away from sensitive areas and antennas. Don't run the wire parallel with wires that are used as signaling in your micro controller. If you must its best to have them cross at 90 degrees.
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Behaviour Based Robotics & Deliberative Robotics - 0 views
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The robots do not build a model of their world they simply act in response to the things they encounter whilst existing there.
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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
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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.
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Alan Turing the inventor of the Turing Test might have been the first to recognize this, in a paper he wrote in the mid 1940's entitled "Intelligent Machines" he suggest that for a machine to achieve some levels of intelligence (his example was" language") it must be embodied.
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Testing a behaviour based systems is quite different from deliberative systems. You can test individual parts of the system, you are able to build up the behaviours the robot will have and then test each for correctness.
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shared by Astro Biology on 10 Oct 14
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Know How Cassini Looking Mysterious Feature Evolve in Titan Sea - 0 views
www.astrobio.net/...rious-feature-evolve-titan-sea
spacecraft cassini space station solar system exploration
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Do you know NASA's Cassini spacecraft is monitoring the evolution of a mysterious feature in a huge hydrocarbon sea on Saturn's moon Titan? Curious to read more about mysterious feature?
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Do you know NASA's Cassini spacecraft is monitoring the evolution of a mysterious feature in a huge hydrocarbon sea on Saturn's moon Titan? Curious to read more about mysterious feature?
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shared by Astro Biology on 28 Oct 14
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Know More About Plenty of Water in Asteroid Fragments - 0 views
www.astrobio.net/...dance-water-asteroid-fragments
asteroid water fragment news from nasa space exploration
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Do you know new study could provide visions about the abundance of water in fragments from a famous asteroid? This research mainly focused on a mineral called apatite. Want to know more about this asteroid?
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Do you know new study could provide visions about the abundance of water in fragments from a famous asteroid? This research mainly focused on a mineral called apatite. Want to know more about this asteroid?
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shared by York Jong on 28 May 07
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Ray's Solder-less Motor Mount Tutorial - 0 views
raysbeambots.solarbotics.net/MotorMount.htm
5star beam diy motor nonsolder photopopper phototrope photovore robot toturial trick
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Set one straightened paper clip aside, you will use it at the end. Bend the two tips of one of the two paper clips as shown.
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Put it in through the fuse clip like this, but make sure the notch in the fuse clip is facing out. (The clip has one edge bent inwards. This is the part that has to face outwards). Study this next picture closely.
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From the position above, bend the paper clip up and then around the lead of the fuse clip as in the next picture.
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First clip -- wire is on the RIGHT side of the fuse clip leads... Second Clip -- wire is on the LEFT side of the fuse clip leads... But remember to make sure the notch in the fuse clip is facing out. (The clip has one edge bent inwards. This is the part that has to face outwards). Follow all the steps above with the second clip and you get this:
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shared by York Jong on 27 May 07
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Short Period Astetics Intelligence - 0 views
home.wanadoo.nl/...others.htm
5star beam circuit diy electronics phototrope photovore robot tutorial
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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.
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All these bots are powered by a 3,3F Gold Cap ( F= farad). You can charge them with a regulated power supply
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When ALI bumps into something it will go backward for a short time and then go forward in another direction, so they will find their way all alone.
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The first one is a light seeker and the second one is a line follower. This version I like very much.
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When you are making the line follower you need to place the small light bulb. The light seeker doesn't need it.
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When bumbing into something it can also reverse for several seconds. The time of going reverse can be changed. I've used 2M2 and 3,3 uF, this will give a reverse time of about 5 seconds
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When you "power on" Bully it will first go backwards for some time. After a few seconds it seems that it doesn’t know what to do, it looks like it’s shivering. Then it starts of going to the brightest lightspot it can see, first slowly and then like "in a hurry". When it reaches the lightspot it makes turns which make it look like it’s happy! In the time doing all this stuff, each bump into a obstacle makes it move backwards for a few seconds. The time doing this can be changed with the 10 uF elco. Smaller means less seconds and bigger means reversing for more seconds.
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shared by York Jong on 27 May 07
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A Bot With Peripheral Vision - 0 views
www.geocities.com/...PVRoller.html
5star beam behavior-based circuit electronics photopopper phototrope robot
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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.
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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.
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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.
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The diodes between the photo-diodes create a constant voltage drop between the inputs of the inverters. They cause a dead band to exist between the thresholds of the two inverters. In a way they cause the circuit to act like a kind of window comparator. Without these diodes both inverters would always be in the same state. With them, there is a small range where their outputs are in opposite states.
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The Slave section has only two diodes (or one LED) between the photo-diodes. This makes it respond to smaller differences in light levels than does the Master part of the circuit
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Cheesy works very well. I?ve had fun making him chase a spot of light from a flashlight around on the floor. He has even been able to detect and react to the flashlight spot on the floor of the brightly lighted lab where I work.
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shared by York Jong on 26 May 07
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Facilitating Robot Learning - 0 views
robotics.usc.edu/...learning.html
5star behavior-based delicious imitation imported learning multi-robot robot theory
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