Bumper Bot Schematics

[Arkorobotics]

Well recently I bought a breadboard and a bunch of different Transistors, Resistors, and Capacitors. Does anyone know the schematics for a robot that has bumpers and when it hits a wall it backs up turns 45 degrees and moves forward again? I am sure it is possible with very few of these things, and with no IC. If anyone has links or ideas please help.

P.S. - I don't want to program it, I want it to be pure electronics.

[Bill_Hancoc]

I know one that uses a photoresister to sense light to follow a line but thats not exactely what you want...but it is pure electronics.
Its in a book i have if you want i can try to find a link to it somewhere

[Arkorobotics]

I know one that uses a photoresister to sense light to follow a line but thats not exactely what you want...but it is pure electronics.
Its in a book i have if you want i can try to find a link to it somewhere
Sure I will take anything.

[John Gutmann]

That will be kinda hard because whether your using continuous rotation servos or a motor controller you will still need a PWM signal and the signal will need to be on a a certain level for a certain amount of time. It is a lot harder to do with pure hardware then you think.

I would say start with something simpler.

[Arkorobotics]

That will be kinda hard because whether your using continuous rotation servos or a motor controller you will still need a PWM signal and the signal will need to be on a a certain level for a certain amount of time. It is a lot harder to do with pure hardware then you think.

I would say start with something simpler. Simple, any idea?

[Bill_Hancoc]

There isnt really a shematic online since it is copyrighted material but i would suggest going and buying the book "Robot Building for beginners" by david cook

it is very detailed and explains how to build it....the website is www.robotroom.com and the bot you build in that book is "Sandwich" is case you were wondering

[John Gutmann]

Simple, any idea?

Something simple as in maybe something that goes torwards the brightest light. hae 2 photoresistors and then the more light the slower the motor moves that way when one side is in light and the other is in a shadow it turns to get them both in the light.

Or......you could always learn to program. doing simple things liek that really isn't that hard.

[sanddrag]

If you can get your hands on a book called Robot Builder's Bonanza I think you'll enjoy it. :)

[Matt Krass]

If you can get your hands on a book called Robot Builder's Bonanza I think you'll enjoy it. :)

Agreed, I own that, along with the aforementioned David Cook book. All kinds of fun electronic circuits for behavior control in both of David Cooks books, most don't require anything more complicated than 555 timers, voltage regulators and comparators for example. The second book does have a few chapters on "upgrading" discrete component robots to use microcontrollers should you decide later to go that route. Gordon's Book has a lot of small mechanisms and techniques for building robots out of simple things. They make a great pair.

[henryBsick]

I am pretty sure I could whip you out a schematic for such a bot with digital logic gates and a 555 IC timer.=, but I don't think I can do one with what you said you have. I will give it a thorough thinking when I am on the drive through at the bank tomorrow.

[bear24rw]

Check this link out
http://www.instructables.com/id/E6PN27M4CPEP286H58/?ALLSTEPS

[Arkorobotics]

Check this link out
http://www.instructables.com/id/E6PN27M4CPEP286H58/?ALLSTEPS

THIS IS PERFECT!! I couldn't have asked for anything more. It's simple and takes no programming (though I love programming).

THANK YOU soooo much.

"Mousebot is a simple bot that uses two "eyes" to sense light and then turns towards the light. A single large "whisker" is mounted on the front of the mouse to detect collisions. A collision with a wall will cause the mouse to reverse and turn then take off in another direction. This project is pretty cheap, if you have a mouse to use the other parts can be obtained for less than ten dollars."

[FIRST JerseyKid]

Something simple as in maybe something that goes torwards the brightest light. hae 2 photoresistors and then the more light the slower the motor moves that way when one side is in light and the other is in a shadow it turns to get them both in the light.

Or......you could always learn to program. doing simple things liek that really isn't that hard.

I designed and built my own custom curcuits and used sensors to make an RC h2 car, from radio shack, to follow the brightest light.

I used a pic18f4620. I amplified the reading with op-amps. And used ref voltages to spread the 10 bit adc evenly across the calibrated light.

If anyone would like the source code or get more info on this email me at FirstJerseyKid@comcast.net

[woody]

You might consider googling "BEAM robotics"; this stuff is fairly simple and generally doesn't use any micro-controllers. Here's a few links to get you going:

http://costaricabeam.solarbotics.net/Circuits/Vores_Main.htm
This has several solar and battery powered light seeking robots.

http://costaricabeam.solarbotics.net/Circuits/Others_Main.htm
The "edgebot" circuits here are similar to what you're looking for, i believe.

http://members.tripod.com/robomaniac_2001/id120.htm
This is a tutorial to build a simple robot using only a few switches that is capable of following a wall, etc.

Regarding the use of PWM signals, its really not necessary. First, you can obviously just remove the controller from a servo and use outputs from some circuits to directly drive the motor. If you need greater current capacity, you can use a chip such as the 74AC245 ("Octal Tri-state Bus Transceiver") as a simple motor driver. You can use one chip to drive 8 outputs, or you can wire sets of inputs and outputs together to deliver greater current. For example, one chip could be used to drive two motors wherein two sets of four inputs were wired together and their outputs were also wired together. If you need still more current capacity, you can stack chips on top of each other (be sure they have the same orientation), which essentially wires all the corresponding inputs and outputs from the two chips in parallel.

This may sound confusing, but if you poke around and do some reading it will all make sense soon enough.

Hopefully this helps. Enjoy your project!

[Cuog]

for all sorts of robotics related stuff, also check out this guy's books: http://robotroom.com
Check out "sandwich" it is the most basic line-follower he has

[John Gutmann]

http://www.parallax.com/detail.asp?product_id=27312 I forgot about this item at the time of my first post. All nice and ready make for you liking.

[Al Skierkiewicz]

Ara,
A real simple solution it to have a simple monostable multivibrator. It can be built with two transistors a few resistor and a capacitor. The object is that the circuit remains in one state until it is triggered, i.e. one transistor is high and one is low. Then when a trigger arrives, the transistors reverse, i.e. the first transistor goes low and the second goes high. The length of time this state remains is dependent on the capacitor and resistor in the timing circuit. Use one of the transistors to drive a DPDT relay. The relay is wired so that in one state it feeds voltage to a motor in a normal manner and in the other state it reverses the voltage to one motor. Use a switch on the front of the car that will close when the car bumps into something. Wire the switch as the trigger, and calculate the length of time a wheel motor needs to reverse to get 45 degrees of rotation. Use that calculation in determining the timing components.

A 555 timer can be wired as a monostable and is almost as simple and cheap as a two transistor monostable MV.