Robots

we have illegal narcotics in america…and i’m curious of why they are illegal.

even if we tap into the issue of brain damage…isn’t that the users choice?, we have no laws against cults that brainwash their followers into their strange ways….why because it’s the individuals choice to decide.

legal drugs and illegal drugs…allot of people question why marijuana is illegal because it’s been proven to be less dangerous then alcohol to the users health…so the health issue isn’t a problem, because the government still allows tobacco, alcohol, and extremely unhealthy consumables to be allowed on the legal market…

I’m just curious of how the government draws the line of invading peoples freedom and privacy, over a substance that can so easily be compared with the same potential dangers as our other legal substances? do they just make it up? and if so, where is the people’s say in this?

It has been suggested that the origin of a number of these laws was racially motivated. Take the case of Harry Anslinger saying "Marihuana influences Negroes to look at white people in the eye, step on white men’s shadows and look at a white woman twice." So, ignorance was a contributing factor to the prohibition of marijuana.

I’ve also been privy to the argument that alcohol producers originally favored making marijuana illegal because it grows like a weed and would cut into their profits.

All laws are created and destroyed through government. So, the People’s say is either through their representatives or by presenting a ballot initiative – like proposition 215 in California. Federal law, however, trumps state law. So any real change would have to come from DC.

There are activist groups that support medicinal users in CA. And other groups (Common Sense for Drug Policy, for example) that discuss prohibition and its toll on society at large. The only political party in the US (that I know of) that vows to end the "War on Drugs" is the Libertarian Party. Disclaimer: I am a member of the Libertarian Party. Additional disclaimer: Libertarians are a third party with, sadly, little influence over the federal government as we know it.

It is the smallest all over the world line following robot.

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In a line follower Bot… how is a track mapped…. what type of mapping is it… note than i am not using CMU cams..so no IP.. its simple mapping….. How does the robot save it in its memory… Please provide me links to these….

I am not an expert on the line follower, but you have to have some form of navigation, either by tracking reference points or by dead reckoning from a "home position". Tracking fixed or known reference points means some sort of radar, sonar, lidar or other direction finding/ranging system, with the idea that the position relative to some reference is located by triangulation. Calculations use trigonometry. You need a range and an angle or two ranges or two angles to external reference points. The system you can carry on board is limited, and that is why people tend to resort to cameras, using a "blob" or two located somewhere in the field of view, then try to extract the information required. The first link hints at this.

The second method is by dead reckoning, where you track the motions of the machine. Thus if you know how far it travels, and also what direction derived from when it turns, you can calculate the current position. The problem here is accuracy. The errors accumulate over time, so eventually you need a "reset to reality" that you might get from a reference point as above. One method of dead reckoning is to use accelerometers. The output of these shows a signal proportional to the acceleration or deceleration. You need X and Y axis accelerometers. The signal is zero when stopped or cruising at a constant speed. The processing is to extract the direction from X and Y, and integrate the acceleration signals over distance, so a distance/speed sensor on the wheels is essential too. The result is to get speed and direction, from which position can be calculated.

One goal of mapping is to record the path followed, so you know where you are/were at any time. Another goal is to compare the actual track with another "reference" track, so the machine can correct its position along the way. Ideally it is a set of X and Y coordinates recorded regularly (at time intervals or distance intervals). It could also mapped as an X,Y and distance from the last point, recorded at each change in direction. The coordinates are referenced to some place that you can call "home". The coordinates are numbers big enough to give the resolution you need in the area you are operating in. In the machine you are talking about it will probably be used in a control loop to get smoother control of direction. Thus the control may be "turn 10 degrees right, and proceed 2 meters". Knowing/mapping the track, the control system can correct for any overshoot in the turn, bringing it back to the actual line it is following.

I expect the line follower robot to be limited in capability because of its size and power supply, as well as cost, so the solutions will need to be innovative. However a ship or a UAV are also line followers in some way. They are easier to map too, because they can use GPS.

It may be possible to get direction and speed using a trailing castor wheel. There are also small low cost accelerometers available. It would be possible to have the line follower tracked from an external reference point that sends a location message to the robot.

Giolianz…
Use the LEGO Mindstorms RIS 2.0 Robotics set to create a robot that will detect a line with its two photoresistor light sensor and follow the line

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Is it better to convert analog to digital before comparing the two values? I am asking this in the context of a sensor input of a line follower robot…. Please state briefly the pros and cons of the two above mentioned chips

If you are building a computer controlled robot, then you already have a computer on board. So just use an A to D and you will have full flexibility with your software. Chances are, you already need an A to D so just use one of the existing channels. If you use a comarator, there is no easy way to have the computer adjust the threshold voltage if, for example, the ambient light should change.

About 8 seconds by my watch.

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Please gimme some model numbers….. Also specify is it ok to use a normal photodiode… This is in context of stopping my line follower bot at a IR chekpoint when the IR leds are ON…… Please recommend a solution for the photodiode. Urgent….. Thanks in advance…

It is possible to get both photodiodes and phototransistors that are encapsulated in black IR transparent plastic.

There are a few factors that would help determine what part to choose. For example is the IR checkpoint IRED just on or is it modulated? If it is modulated what is the modulation frequency?
If it is modulated at a standard frequency used for IR remote control you could use a device that has built in circuits for amplifying filtering and detecting the signal.

If you want just a phototransistor

http://www.fairchildsemi.com/ds/QS/QSC112.pdf

digikey QSD723-ND

If you want just a photodiode

http://www.semicon.panasonic.co.jp/ds2/SHE00037CED.pdf

digikey PNZ323B-ND

a photodiode with amp and filter for 38 khz
digikey PNA4702M-ND

http://www.semicon.panasonic.co.jp/ds2/SHE00053BED.pdf

You can order online from digikey at www.digikey.com

It would make sense for the checkpoint IR emitter to be modulated because incandescent lights and sunlight both emit IR as well as visible light. You may need more information before you can pick the best part.

A Lego biped that can follow a dark line. For more info, go to http://blake-foster.com/project.php?p=22

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Something in the robotics domain. Simple but not too popular.
I saw that the internet is full of line-follower robot and maze-solving robots. So I really don’t want the same very common project. So, any suggestions?

FIRST Robotics is very popular, and not the best (in my experience). There are very limiting design constrictions, and not much for the kids to do. I was on a FIRST team about 4 years ago. The mentors from GE did all the fun parts (programming the BASIC Stamp, deciding how it was designed, etc.).

Anyways, there are many possibilities. Lawn Mower robot, robotic system to take the trash to the curb, vacuum cleaner (take a shop vac, put some motors, casters, sensors, and a system to move the hose around), etc. Autonomous Sumo is fun. I started with the maze solving, fire-fighting robots in High School. Now I’m trying to get all of the parts together for a LEAF series robot.

http://www.leafproject.org/

What microcontroller will you be using?

Check this out:

http://www.parallax.com/propeller/index.asp

Have fun!

http://calogerolombardo.altervista.org/
This is my first line follower robot. It is realized with 3 sensors QRB1134

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