CPU/Computer controlled motor switches

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LittleGirl

4 posts

Wannabe Geek

#109466 20-Sep-2012 10:56

Hi, I am working on a robot that is going to run on its own computer programing. However, I do not know how to program a CPU or hardrive for my robot. Furthermore, I am using air muscles and puller systems for the movement of the robot, except I need to control those functions with a computer. However how do you do that?

hellonearthisman

1819 posts

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#688701 20-Sep-2012 11:31

Arduino is what your looking for, it's a simple to use micro-controller that connects to relays so you can control other bits of hardware.

LittleGirl

4 posts

Wannabe Geek

#688726 20-Sep-2012 11:57

Yes I already know about them, however it says on their website that these circuit boards respond to outside occurences? I don't know if I'm being clear, but for example, it responds to light or sound. Also it is supposed to connect to a computer. What about a CPU by itself or some other harddrive/ hardware?
Also can you program those circuit boards?

geocom

594 posts

Ultimate Geek

Subscriber

#688746 20-Sep-2012 12:10

The Arduino is what you want to read analog(Light Temp etc) signals. It has 6 Analog inputs. To connect it to a computer you will need to buy either a Ethernet Shield or buy the Arduino with ethernet.

The other option is you could use a Raspberry Pi as this has ethernet built in and has a 32bit CPU for around the same cost as the Arduino what the Pi is lacking is Analog inputs so you would need to buy some ADC converters to convert the Analog signal to digital or buy a Arduino and attach it by USB.

If you need power go for the Pi. If you need simplicity go for the Arduino.

You will also need something to drive the motors as the Arduino can only output about 40mA and i think the Pi is much the same. That could just be something as simple as MOSFETS to something more complicated like a motor controller. You will need to test the motor under load as they can suck up the power. Which will effect your choice in controller.

Edit yes you program them. The chip is a ATTMega the Arduino is the programming side of things.

Geoff E

floydbloke

3522 posts

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#688747 20-Sep-2012 12:11

Raspberry Pi migth be an option, it exposes GPIO pins and common protocols to interface with other hardware like I2C are also there.

Arduino has inputs as well as outputs, so this also allows you to connect sensors for responding to light, sound etc.

For a less steep learning curve, maybe even consider a Lego NXT.

Did Eric Clapton really think she looked wonderful...or was it after the 15th outfit she tried on and he just wanted to get to the party and get a drink?

Niel

3267 posts

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#688892 20-Sep-2012 15:19

+1 for Lego. For 11 years they made a loss until they came up with Mind Storm, made it hackable, and it became an overnight success (from documentary on Discovery Channel). You buy a basic kit and it contains Bluetooth (and WiFi?) for controlling your robot.

You can never have enough Volvos!

LittleGirl

4 posts

Wannabe Geek

#689145 20-Sep-2012 23:02

Thanks for the advice. I will shop around a bit. But, I don't understand something: do you directly program the different switches like Arduino or do you connect it to another programed computer. Also, does Ardino only connect into computers or does it also connect into CPUs/Circuit boards? I am trying to make the robot compact by including the CPU inside the robot, so that it acts on program and I don't control it manually. However, I am not sure how to do this. So far I just compiled the code in C++ and casted the metal parts of the robot, I am having trouble figuring out how to control the limbs and ect.

geocom

594 posts

Ultimate Geek

Subscriber

#689292 21-Sep-2012 10:53

The ATMega it self is a very basic 8-Bit CPU. Arduino is a language built on top of the ATMega. So it can run stand alone or it can communicate via Serial Communication over USB or you can use Ethernet and control it via TCP/IP. It can also go via wireless such as bluetooth and wi-fi or Zigbee but these will be add on boards.

So on your computer you can create a script to send commands to the Arduino via either method. So on the computer I can start up a serial connection and just send F(or some other key) the Arduino can then tell that you have sent the letter F and then do a task based on that. The Arduino can also send data back so it can tell the computer when the task has been done.

The Arduino has a set of Pin's that are GPIO(General Purpose Inputs Outputs) These pins can be set High and Low so in effect the Pin's on the Arduino are Computer Controlled Switches. The only issues is that they can only output about 40mA which will be far less than the motors will require. To fix this what you need to do is add MOSFET's this will let you put more current into the motors.
More info about this here.
http://bildr.org/2012/03/rfp30n06le-arduino/

There is loads more info about the Arduino on wikipedia
http://en.wikipedia.org/wiki/Arduino
There is also more examples here
http://arduino.cc/en/Tutorial/HomePage
More about the Arduino serial communication.
http://arduino.cc/en/Reference/Serial

Geoff E