Let's Make Robots!

The new beginning

Hello Robot-creators!

It has been a long time since I was last active at this site... Mainly because I've been busy making stuff like this:

                                                           Billede187LMR.jpg

(Bidirectional 16-bit databus btw).

It's quite sad actually, now that I see all those cool robots that you've come up with, and all I have is stuff like that on the pictur above. I want to make something useful! Or at least entertaining... :)

Last time I had a "robot-rush", I bought a lot of shiny things (Arduino, SRF05, 3D Accelerometer etc.) and I learned how to use it but really never build any cool robots... This has come to change now!

To start with I want to make a Line Follower! My electronics teacher wants me to build a robot to compete in the DTU Robocup (Danish) this spring. My goal is of course to win! But I will be more than happy if I can just make something that won't self-detonate, before it has reached to first checkpoint.

I want to use PIC's which I've been trying to learn how to use during the last month. I'm using the 16F628 with the MPLAB assembler. I find assembler quite interesting because you really have to study the datasheet, and figure out how these tiny black plastic-things work, before you can use it: a great learning experience!

My school is providing the materials and I think I'm going to need:

  • PICs
  • Light Sensors
  • Motors (DC and Steppers)
  • Motor drivers
  • Battery
  • Robot-base

 Now I really hope you can give me some advice on how to do this. I have a couple of questions:

  • What is your experience with different line-detect-sensors, do you have any experience with the CNY70?
  • How can I make the robot more resistant to ambient light? Should I pulse the sensor?

I've considered a 3-whell design like this:u

Robot_Paint.jpg
The question is if I should equip the two real wheels with a motor each, for individual speed control. With the front wheel as a dummy-wheel the steering is done by the drive-motors alone.

OR

I could make the two rear motors dummy and the both drive and steer the robot with the front wheel (DC motor to drive, Stepper to steer).

I hope that I manage to create a robot and that I manage to finish it before the Robocup! And at last, I hope this project will be the beginning of many new robot adventures!

 

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There are two things you can do to to reduce effects of ambiant light. First of all, have the sensor close to the ground so that less light can get in or have a shield arround he sensors. Second, as mentioned in Frits's Amanda LDR, take readings with the LEDs off as well as on and subtract one from the other.

Just wondering, what exactly is a bidirectional 16 bit data bus?

The 4034 can be used in a lot of different applications. The one on the picture just takes 16 parallel bits and transfer it over a serial connection (using 3 wires: clock, data, and reset). The cool thing about a bus is that you can have several sources talking on the same set of wires. You just need something to control when who is speaking. It can be done because the 4034 has a tri-state port, so it can be physically removed from the rest of the circuit when it is not sending data.

I hope that helped :)

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Dennis L

Can you please speak in english? :)
Four wheels is not a good option for a line follower. Simply because line followers do alot of sharp turning, and it takes longer for a robot with two back casters to turn. Your best bet is to follow your picture, with differential drive, and one centered rear caster. You get balance, manuervability, sturdiness, and its cheaper! G'luck

 

It was my idea to use that method too. You're right BOA a skidsteer would be cool! I will consider comming up with a more excotic robot for the Robocup next year :).

For now I want to do something pretty simple, that at least will go around the track with a minimum score.

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Dennis L

I dunno. A skidsteer line follower would be pretty unique...
Welcome back :)