Robot Wall Racers

This is updated, reason is here


 

A video in better quality than YouTube & Google is here

How to make Robot Wall Racers yourself, see here

The car-chase was made by holding a camera on a stick, chasing the cars around. Some clips where made by placing the camera on a record-player. All editing was done in the standard "free" program that comes with a Mac, called iMovie. It is a nice program for light editing.. but phew, it was pushed to make this

The second video shows some work with the skid-turning. It also shows improved handling in general.

Notice how it sometimes mis-judges when the wall is not 90 degrees, but has bumps. But also how it handles getting out again :D (Me proud, love this, think it is cool, it drives so much better than what I can do with remote myself)

Of course I could just give it some more space to turn in the code, to drive more "safe", but I kind of like it to be tight :) And notice hw it never bumps into anything else - the polystyrene-blocks would fly right off if it hit them.

I have added an extra battery for more power.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Your home is a racing track, you just do not know it.

Look at your floor where it meets a wall.

Between 30 and 70 cm from that goes an imaginary path, following along the wall.

That is the racing track!

Where the wall meets another wall, or there is an obstacle, the track follows in a smooth path, always 30-70 cm away, on the floor.

The track returns to where you started, you see! :)

It is a full racing track:

You can time how long time it takes for a little robo-car to take one round. You can then try to improve the code, and time it again.

 

If you make the car like this:

One sensor (Could also be infra-red or whatever) looks ahead, another looks to the right. Then code could be something like this:

main:

If something in front, turn left, go to main.

If something closer than 30 cm to the right, turn left, go to main.

if nothing in front and something closer than 70 cm to the right, drive ahead, go to main.

If nothing to the right closer than 70 cm, turn right, go to main.

 

A car is racing your home!

It can be timed how long before passing by the same line again and again.

But a single car is just test-labs, no?

 

Now take 2 cars with the excact same setup as above, let's say a red car & a blue car. Now it get's interesting!

If red car is behind blue car, what does it do?

Well.. Something (blue car) is in front, so we turn left to take over.. until nothing is on the right, so we pull back.. That is trying to take over!

At a point the blue car is turning left because there is something in front.

Then the red car will have the inner track..

 

What is actually going on, is that one car is behind, but is "strugeling" to take over.. when it is in front, the other will fight to get ahead.. and we have a full race :D

You can take Red & Blue and place them next to each other, next to the wall; They will both drive full speed ahead, until a turn, where the inner car will have advantage. But then..

Wall Racers are born, ladies and gentlemen.. I had these 2 cheap RC cars with crap maneuvering abilities, and thought of what I could do with them. Crap - but still; They sort of drive like cars - not like differential steered robots.

It has ben quite simple, have experimented with AZ8222's instead of motor drivers. And just a Picaxe on a standard board, simple and fast.

Of course, when turning angle is not enough to avoid obstacles, maneuvers with reverse and 3-point turns must be done. But this is why we have a microcontroller, and it is not spoiling the fun - on the contrary :)

 

Finds the hidden racing track in every room.. and races it!

  • Actuators / output devices: 2 motors each
  • Control method: autonomous
  • CPU: Picaxe 28X
  • Operating system: Picaxe
  • Power source: 4 CC cells
  • Programming language: Picaxe basic
  • Sensors / input devices: SRF05
  • Target environment: any room

This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/robot-wall-racers

Good idea! Maybe an IR
Good idea! Maybe an IR receiver in the front of each and an IR LED in the back of each would help with overtaking.

No guys - you don’t get the

No guys - you don’t get the beauty in the math :slight_smile:

If any extra, all we need is a bumper at the back to ensure it knows if it is reversing into something when doing a 3-point turn.

So far it is just theory - I had the idea late last night. But I might get the time to build them later today if all goes well - so we will see if it works as I hope :slight_smile:

/ Fritsl

hey frits you know what! you
hey frits you know what! you just entered the toy car challenge. =) i think

Not only that - I am going

Not only that - I am going to win it! =) I think!

:smiley:

/ Fritsl

"Toy" That’s exactly what it is

Hehehe. What do you think you’re going to win with that tiny little thing? THIS will (eventually) do the same thing, but outside in the big bad world!

MinesBiggerThanYours.jpg

God created the integers; all else is the work of man - Leopold Kronecker

"The same thing"? My "Wall

"The same thing"? My “Wall Racing-concept”?.. or “just drive around and avoid obstacles”?

/ Fritsl

Looks like fun. Too bad
Looks like fun. Too bad those SRF05 are so expensive! I chopped some of my old RC toys that didn’t work apart and harvested some high RPM motors. I never realized RC toys could be so fun! I may try to take the board out of it and integrate the radio control with a PIC board… Backwards of what you have done, but still similar :wink:

CrisTheCarpenter did a

CrisTheCarpenter did a similar project, I remember :slight_smile:

/ Fritsl

R/C

I’ve had a R/C remote send an input to a PIC. It’s dead easy. The waveform output by the R/C receiver is IDENTICAL (surprise, surprise) to that required as the input to R/C servos which is so well dcouemnted all over the web.

God created the integers; all else is the work of man - Leopold Kronecker

Haha!

No. I was having a laugh. I’ve not considered an entry for this competition, although I probably should. I could use those tracks.

God created the integers; all else is the work of man - Leopold Kronecker

nice pictures =D greath
nice pictures =D greath project!!!

Oh man, these robots, like

Oh man, these robots, like all of your robots, look so fun. One MORE idea I want to play with :slight_smile: The speed, I think, is the big think that makes these appealing. My attempt at controlling an R/C car with a microcontroller didn’t work very well, because it couldn’t process the input from the sensor fast enough to react in time. But these can aparently react even when driving at full speed, and that makes them really fun :slight_smile:

Dan

Photos and Controllers

It helps that Frits appears to be bloody brilliant at macro photography!!

My experience the first time I tried this (with my car above) was that I had no way of reversing a 10A 7.2V motor! I couldn’t find a suitable H-bridge and I was (as ever) on a budget that didn’t allow an electronic speed controller. I should have stuck with the mechanical controller and driver the servo. In the end I used a DPDT relay but I didn’t understand the concept of waiting for the motor to stop before reversing direction. Yes, there were sparks.

I am using 4 DPDT relays as

I am using 4 DPDT relays as well. TheCowGod showed e that they could be used to revert current (thanks), and I use another to turn the motors on/off.

I Know that 2 of the relays has one set too many pins etc, but yadayada. It was what I had :smiley: See pictures here: http://picasaweb.google.com/fritslyneborg/WallRacers

To both of you; I think the challenge is the programming. My initial attempt did bang and crash a lot, SRF05’s where torn off etc… So I took my own medicine, just started with driving ahead and stopping before a wall, then… and then…

I would never be able to “just program this”. One thing, example; I discovered that it takes a 20 miliseconds (20 ms!!) yank to one side JUST before reversing, and then turning etc to make a skid turn come out right (skid to the right side).

My first code did not have that kind of details, but then I programmed layer upon layer of things that works…

It also helped me to insert a potentiometer before the rear motor, and film the behavior - all to analyze / get slow motion… Because there is no way in hell I would be able to figure out how to create the code else. These things just fly around, gives a large impact on a wall (they are heavy now), continues to flip out afterwards … and it is impossible to remember “what went wrong”.

But with these tricks it was quite easy, spend perhaps 2-6 hours of programming & testing to get it completely right, and it was easy & doing well from first (simple) line: Stop before wall.

This approach also makes it drive “like a person”, IMHO.

/ Fritsl

Rgarding the photos

Regarding the photos, I tried to give my knowledge here:

https://www.robotshop.com/letsmakerobots/node/466

/ Fritsl

Coding Nuts
See, I’d love the coding. I’d be thinking: If I know my distance over time, then I know my speed. If I have three samples of distance, I know my acceleration. Couple of laps to measure the braking constant of the rubber against the wood floor and try to create an algorithm that “learns” when to brake without hitting the wall andlearns when to “yank”.

Wow! My code is only 210

Wow! My code is only 210 bytes :smiley:

Am optimizing, will make walkthrough!

/ Fritsl

Awesome, I love the idea,
Awesome, I love the idea, the implementation. gimme more :slight_smile:

very very nice,good stuff

very very nice,

good stuff always rise from simple ideas.