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541  Using Arduino / Project Guidance / Re: multiple input monitoring on: January 13, 2014, 01:13:16 pm
ah... you're not reading the inputs in that if. You did digitalRead's on the fly in the ones where you set the LEDs, but didn't store those so in the main if where you set the relay, it doesn't know the status. (edit... ie you're checking if the pin number is high, not the value of the pin's input)
542  Using Arduino / Project Guidance / Re: multiple input monitoring on: January 13, 2014, 01:04:49 pm
Presumably  at least one of the LED1-6 is on, so you know at least one input has gone low?
543  Using Arduino / Project Guidance / Re: multiple input monitoring on: January 13, 2014, 12:39:41 pm
Quote
any idea's

Yep... show the whole code so we can see the settings of the pins and so on, and wiring....
544  Topics / Robotics / Re: uArmⅠ:An open source robot arm on: January 13, 2014, 10:08:32 am
I'm struggling to get the longer FF standoffs. But one guy quoted MF too, so that gets screwed into a shorter FF and end up with a FF of the right length.
545  Topics / Robotics / Re: uArmⅠ:An open source robot arm on: January 13, 2014, 06:21:42 am
Fetched my laser cut parts today  smiley-cool

EDIT.... checked that the servos and bearings fit snugly in their holes, which they do, so the cutting is good. The two halves of the gripper tooth together nicely.

Now to gather all the orther little bits-and-pieces.
546  Topics / Robotics / Re: uArmⅠ:An open source robot arm on: January 12, 2014, 09:30:04 pm
I've emailed the local Grainger guy... thanks.
547  Using Arduino / Motors, Mechanics, and Power / Re: 10 pound motor on: January 12, 2014, 02:16:30 pm
Don't forget the mass of the motors and the chassis and so on.....
548  Topics / Robotics / Re: uArmⅠ:An open source robot arm on: January 12, 2014, 01:58:24 pm
Quote
I can't say for certain, but I would bet McMaster-Carr would have every fastener part needed. Between them and Grainger, among a few others..

I'm in South Africa where I don't know of those brands. I've tried a few places. My brother suggested one chain I hadn't thought of, I'll try them. If I can't find the right ones, I'll use a long screw with a tube-like spacer instead.

Re the servos, my HK hobby servos are 4.3kg cm ones with plastic innards. The 10kg cm steel ones would be nice, for sure.
549  Using Arduino / Motors, Mechanics, and Power / Re: 10 pound motor on: January 12, 2014, 01:52:03 pm
You need to research elementary mechanics... gearing and so on.

The size of the wheels makes a difference for example. A motor of given torque with a small diameter wheel will exert a greater force than the same motor with a huge wheel.

If  you need to exert a pull of 10lbf, that's the force you need at the circumference of the wheel. If you have a wheel of say 1" radius, that's a torque of 10 lbf.in. Halve that if you have two independently powered wheels each taking half the load.

EDIT: This might help.... note what they say about start-up torque.

Once you find a motor of the required mechanical characteristics, you then look at its electrical characteristics and choose a driver- an h-bridge maybe- that meets those needs. Then you figure out how to interface that to the Arduino.
550  Using Arduino / Motors, Mechanics, and Power / Re: 10 pound motor on: January 12, 2014, 01:38:28 pm
No motor's really compatible: you always need something in between, maybe just a transistor, but often an h-bridge. In either case, you control the motor with a signal from an IO pin through the intermediary. The transistor or the h-bridge is the part that needs to be compatible.

Also, motors aren't measured in force- they exert a torque: force at a distance. And gearing always helps...  smiley-cool
551  Using Arduino / Programming Questions / Re: Hello Forum need help with if, else on: January 12, 2014, 01:15:37 pm
A number of people here me included will not access dropbox to see your code. You can attach it by going to Additional Options below the typing area though.

My advice is to put some Serial.prints in the different "legs" of the ifs, that way you can see where the logic leads, eg:

Code:
void loop ()

{
   int distanceInchesFront = scanFront();

   if (distanceInchesFront > 1){
   Serial.println("leg A");
   if(distanceInchesFront > objectMid){
 Serial.println("leg B");
         driveForward();              
   }else{
 Serial.println("Leg C");
          driveBackwardTurnRight();
             }
 }
}
552  Using Arduino / Motors, Mechanics, and Power / Re: Motors are beeping instead of turning on: January 12, 2014, 12:52:58 pm
If you're powering the Arduino with 6V that may not be enough and the Arduino itself might not be operating correctly. Although 6V is the minimum, 7V is recommended.

http://arduino.cc/en/Main/ArduinoBoardUno

Quote
The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts
.
553  Using Arduino / General Electronics / Re: Ran out of +5V pins on: January 12, 2014, 10:21:57 am
Well that's a matter of current, and from what I've seen, battery suppliers are notoriously bad at saying how much current a battery can provide. They might give an indication mAh, which is a measure of energy (at least when you multiply by volts), but don't seem to give power, which is what amps tells you (when multiplied by volts.)

If you were using a wall-wart say, it would be simpler since those tell you the current they can supply, and you just need to add up the currents of your components and see if it's less than the supply....

See if you can find current supply figures for your make/s of battery though.....
554  Using Arduino / Project Guidance / Re: I have problem in space... arduino uno on: January 12, 2014, 08:35:36 am
I think we're all having difficulty understanding why you think the sketch is too big. What did it say in the console to make you think that. Please post the actual message.

Last you posted about console messages yesterday says:

Quote
Sketch uses 7,118 bytes (22%) of program storage space. Maximum is 32,256 bytes.
Global variables use 384 bytes (18%) of dynamic memory, leaving 1,664 bytes for local variables. Maximum is 2,048 bytes.

.... we're not understanding why you say the system says your sketch is too big, when it says it's only using 22%.

You were given suggestions about the message you did quote- the avrdude one- which might be to do with communications rather than space, yet you didn't comment on that.

Also, I personally don't understand how you managed to "finish" the project and only then find out it's too big (if it really is...). Do you mean it compiled and ran all through development and then a further addition to the code made it overflow?

We empathise with your position, but to be honest, you're not helping us to help you.
555  Using Arduino / Project Guidance / Re: Using pushbutton to move within modes of LED flashing operations on: January 12, 2014, 05:34:01 am
Look at BlinkWithoutDelay in the IDE....  File > Examples > Digital.

Also look at Nick's state machine tut.
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