Older blog entries for kittipat_0541 (starting at number 4)

I was working with the simulation model for intelligent vehicle last night using just basic components like the infrared LEDs and LDRs to developed a program that would avoid the rear end collisions in car. Using just one OpAmp in comparator mode, I linked the car models with the computer program developed on VB and able to get 2 detecting ranges to keep track of the two cars' distance. However, I found out something so strange about using parallel port that is it works differently (more precise I guess) if you join its ground pin to the ground of the external circuit. I tried not joining them; it gave almost the same result of the input reading but in a not very stable manner... I kinda repeat it several times to confirm this phenomena, and yes it is. Does my printer port has something wrong in it?

Can anyone suggest me the site where I can find more detail about some simple or homemade kind of sonar? Love to have it. thanks kittipat_0541(at)yahoo.com

My university is trying to arrange a robot camp for 12th grade kids from local schools. Sixty students are attending the camp. We will try to have a line tracking robot competition for them (group of 3). Providing only the basic program in assembly and circuit diagrams, we would like them to try to their best in modifying it to get the best performance line tracking behavior. Do you think they can finish it in a day? Any suggestion for shopping list and competition's regulation? kittipat_0541 (at)yahoo.com

28 Dec 2005 (updated 28 Dec 2005 at 02:31 UTC) »

Instead of having the Volts and Nuts sort of magazine, we do have our own electronics (I would prefer calling it "robo-tronics") magazine called "Hobby Electronics". It's been published since the last fifteen years I guess. Sad thing was I was trying to build a "worm" looking robot according to their design. After I soldered everything together, it didn't work! The worm, which was supposed to be going around zigzag and once hit the front wall it will make a sort of u-turn, kinda went straight, and it kept going straight once hit the wall!

It was meant to be a christmas gift to my nephew, who seems to be so much interested in robots, that I like to inspire him. Anyway, he found it out and played with it (without me knowing). Finally, he ended up burning the motors cuz he kept it ran against the wall. Poor him. He said "I never know that robot can smell (burned)"!

The next vol. from Hobby Electronics made some correction in the previous volume's circuit, but I didn't see them correct the 'worm'... sad, isn't it?

27 Dec 2005 (updated 27 Dec 2005 at 16:31 UTC) »

My team mate in robocup team has run out of memory space in the MCS51 microprocessor, but we still have the whole program of the PID algorithm to get the steady speed of the motors that run the omni-wheels. We consulted the distributors and the manual, but they only suggest us to use external memory device. With limited space in the robot circuit, we can't bear having more electronic device into it. So, we found "xregister" and used it without knowing what it is. The result turns out to be the inconsistance of robot responses, which we have no clue of the source. Has anybody heard of this "xregister" thing? Please advise

27 Dec 2005 (updated 27 Dec 2005 at 16:20 UTC) »

I am trying to work on the intelligent vehicle only in just the part of the rear-end collision avoidance. For local vision (of course, Thai student doesn't have enough to pay for the GPS, which cost something like $5,000), I was able to find the ultrasonic from underground market, which costs only US$50. With that operating already, I still do not know how to integrate the braking system. Is it possible without the robot arm stepping on the brake? Can anybody kindly suggest? kittipat_0541(at)yahoo.com

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