Show Posts
Pages: 1 ... 33 34 [35] 36 37 ... 225
511  Using Arduino / Project Guidance / Re: 12v Relay Module on: January 15, 2014, 07:17:12 am
correct.. (see reply 5 - shows 1/2 of our board) 


It can't be half, that's what I asked above. You show 3 pins and say "x2" at the bottom- that would make 6 pins and there are only 4
512  Using Arduino / Project Guidance / Re: 12v Relay Module on: January 15, 2014, 05:03:25 am
scetch...

But there are only 4 pins... 2 marked 12v and 2 marked Gnd. I agree there should be 2x 5V input pins, but I don't see them on the pic in the link.

Looking at the pic of the underside of the board, it looks to me as if one of the inputs takes 12V to both relays, and the other one on the other end of the inputs takes the input signal to both transistors.

So it might be that both relays get switched together?
513  Using Arduino / Project Guidance / Re: 12v Relay Module on: January 15, 2014, 04:50:32 am
Yeah but going by their narrative in the one link, there should be a 12v input to drive the relay coil AND a 5v input to "tickle" the transistor....

Follow the traces on the board to see where the transistor base comes out...
514  Using Arduino / Project Guidance / Re: 12v Relay Module on: January 15, 2014, 04:16:16 am
Hmmmm deleted my previous comment....

It's not clear from the pic where the 5V IO goes....
515  Using Arduino / Project Guidance / Re: Reversing DC motor with Arduino Leonardo and L298N on: January 15, 2014, 01:34:10 am
Sorry... maybe this is clearer...

Each motor is controlled by 3x 298 pins: 1x Enable and 2x Input. The enable is PWM'd on one of your Arduino outputs. The 2x inputs are given opposite polarity on 2x Arduino outputs, say high and low digitalWrites respectively. That gives a + and - on the motor outputs, and let's say that's "forward"... and those + and - are pulsed for speed according to your PWM input.

So to "reverse" direction, you need to swing the Arduino output digitalWrites to give low and high (as opposed to high and low) on the inputs to the 298... that in turn comes out the other side as - and + as opposed to + and - and turns the motor the other way.

516  Using Arduino / Project Guidance / Re: Reversing DC motor with Arduino Leonardo and L298N on: January 15, 2014, 01:15:18 am
(The 2x inputs per motor are just reflected back out on the respective 2x outputs, just at the right voltage and current for the motor. So there are 3x pins per motor: the enable and two inputs. PWM the enable, and have direction polarity on the inputs = direction polarity on the outputs but PWM'd)
517  Using Arduino / Project Guidance / Re: Reversing DC motor with Arduino Leonardo and L298N on: January 15, 2014, 01:11:39 am
See my EDIT above...

There should be 2 pins to a motor, which I didn't explain well.

There should be two Arduino -> 298 signales per motor too... 5/7 and 10/12... those you need to switch from high/low to low/high
518  Using Arduino / Project Guidance / Re: Reversing DC motor with Arduino Leonardo and L298N on: January 15, 2014, 01:05:41 am
Add something along these lines to your code.

Code:
if (sensor1 == low && sensor2 == low) {
// do whatever digitalWrite magic you need to reverse the motors.
}

Reverse should just be a reversal of the IO pins' polarity to the motor.

EDIT... shouldn't all 4 outputs from the 298 be connected?- 2 & 3 to one motor, 13 & 14 to the other. Those are the polarity you reverse.... high/low becomes low/high
519  Using Arduino / General Electronics / Re: How does wire length affect commponents on: January 15, 2014, 12:52:48 am
Good question and I don't know the answer. Only posting here so I'm in the loop when answers appear... I have an LM35 also, but it's just on the 200-300mm wire the breakout board came with.

I guess one could easily measure the voltage at the end of a long wire and see if it's still 5V as supplied. Then measure the signal voltage for a stable temperature and see if it's the same with a short and long wire?
520  Using Arduino / Project Guidance / Re: What kind of sensing could I use? on: January 14, 2014, 09:15:44 pm
Didn't we do this a year ago or so?

Must say it rings a bell, but I cba to search.
521  Using Arduino / Project Guidance / Re: Autonomous Vehicle - what components? on: January 14, 2014, 01:19:49 pm
Hell yeah, if you have budget, go for that. The intelligence part is the difficult bit, so making it easy on yourself from the building pov makes good sense to me.
522  Topics / Robotics / Re: Code to control 4Wheels robot on: January 14, 2014, 01:11:40 pm
Quote
We got 4 motors , and we need to know how to connect them with the Arduino Uno and then how to do the code
Well you didn't say what the motors are, so I'll assume they're DCs not steppers or servos.

So have a look at these tutorials as a starting point: simple transistor or IC h-bridge.
523  Using Arduino / Project Guidance / Re: Autonomous Vehicle - what components? on: January 14, 2014, 12:49:30 pm
Yes it would make sense to get a chassis with the motors and wheels. Some have a plastic or metal chassis with lots of holes and slots cut in, so it's easy to attach stuff with small screws and even cable-ties. The holes make it easy to pass wiring around the parts too.
524  Using Arduino / Programming Questions / Re: hall effect tachometer problem on: January 14, 2014, 12:32:37 pm
Just as a matter of interest, and probably not germane to your problem, I read on the forum that it's better to use a falling edge with the interrupt pin pulled high. I made these changes to that code recently, when I measured the speed of a cpu fan using its third wire.

Code:
   pinMode(2, INPUT_PULLUP);
   //attachInterrupt(0, rpm_fun, RISING);
   attachInterrupt(0, rpm_fun, FALLING);
525  Using Arduino / Project Guidance / Re: Autonomous Vehicle - what components? on: January 14, 2014, 12:26:14 pm
Quote
The L298 solutions are pretty much all that I have found so far........I also understand a 4 x AA battery to power the system isn't enough for some people :S

Check the specs for L298s- you'll see they have a voltage drop of (I speak from memory) 2V minimum, rising to 3-4 at higher currents, so if you start with 6 you don't have much left to drive the motors. But they are ok as long as you throw enough volts at them.....
Pages: 1 ... 33 34 [35] 36 37 ... 225