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1561  Using Arduino / Project Guidance / Re: Measuring tiny intervals on: February 21, 2012, 10:52:13 am
Hi,
    With regards to the smallest interval that Arduino can measure, I saw that at the hardware level timer1 has an 'input capture' facility that I would expect to be much faster and more accurate than calling micros().

    I have not used it myself but I have had it at the back of my mind to experiment with it, so if no-one else comes up with anything, I will have a go at using this to measure very short intervals and post my code/experience over the weekend.

If you want to have a go for yourself, its in the ATMega328 datasheet in the 16 bit timer section and I am sure there are examples for using it if you search around.

Duane B

rcarduino.blogspot.com
1562  Using Arduino / Installation & Troubleshooting / Re: OptiLoader Help ! on: February 21, 2012, 09:23:29 am
Hi,
   I think that in my case I had one or more pins connected wrong, I have since managed to program 3 out of 6 ATMega8's I am assume that for the 3 I can't program I have locked myself out by sending junk to set the fuses while the wiring was not correct.

Let me know if you find out its down to something else, good luck,

   Duane B

rcarduino.blogspot.com
1563  Using Arduino / Sensors / Re: Problem with IR receiver and Arduino Uno on: February 21, 2012, 06:40:09 am
Hi,
   Its possible that you IR Receiver and IR Transmitter are in different ranges. The receiver I use is tuned to signals around 40Khz, but from what I have seen others may be above or below this range.

   A simple way to check whether you IR Receiver is working is to create a standalone circuit with the receiver connected to an LED.

There is an example circuit using a few AA Batteries an LED and a Resistor here, there is also lots of useful background information -

http://www.ladyada.net/learn/sensors/ir.html

Duane B

rcarduino.blogspot.com
1564  Topics / Robotics / Re: Need help with RC and arduino on: February 21, 2012, 12:47:01 am
Hi,
   People have pointed you to good resources, however you do have to do some work yourself. Here are some pointers to get you going

1) If you use the code from here - http://rcarduino.blogspot.com/2012/01/how-to-read-rc-receiver-with.html

It should print the RC Input value to the serial monitor, have you done this ?

2) If yes to 1) after then after the line Serial.println(nThrottleIn);  you can add some code to turn one LED on if nThrottle in > 1500 and the other LED on if nThrottle in < 1500.

Over to you,

Duane B.

rcarduino.blogspot.com
1565  Using Arduino / Programming Questions / Re: Interrupts from IR Receiver? on: February 20, 2012, 01:48:48 pm
Hi,
   I am able to access it directly, however it may be cached on my machine. I don't want to clear the cache to find out so lets see if the OP can have a look for us.

Duane B.

rcarduino.blogspot.com
1566  Using Arduino / Programming Questions / Re: Interrupts from IR Receiver? on: February 20, 2012, 11:42:56 am
Hi,

something like this ?

http://www.ladyada.net/learn/sensors/ir.html

Duane B

rcarduino.blogspot.com
1567  Topics / Robotics / Re: Need help with RC and arduino on: February 20, 2012, 05:01:44 am
Hi,
   You also do not indicate if you are using hobby quality of toy quality radio control systems. In the case of toy quality, the signal is on or off, in the case of hobby quality, its mostly empty space with short pulses, you would need very different code depending on which it is.

See here for details of hobby quality signals - http://rcarduino.blogspot.com/2012/01/how-to-read-rc-receiver-with.html

Duane B

rcarduino.blogspot.com
1568  Using Arduino / Motors, Mechanics, and Power / Re: Servo sweep speed controlling with rc transmitter on: February 19, 2012, 02:27:06 pm
Hi,

EDIT : Rewrite of a previously confusing response.

  At the moment your code is inside out for what you want to achieve. You should move you if statements inside a single loop. At the moment you use if to check a condition and then get into a fixed loop, you should turn this around to that you check the condition inside the loop. This will also allow you to deal with the special case of <5 which I assume means stop sweeping, return to center now and then stay there.

Duane B

1569  Using Arduino / Programming Questions / Re: ISR() External Interrupt Accuracy on: February 19, 2012, 12:25:56 pm
Hi,
   You could speed up your ISR by using direct port access instead of digitalWrite, see here -

http://www.arduino.cc/playground/Learning/PortManipulation

Duane B

rcarduino.blogspot.com
1570  Using Arduino / Programming Questions / Re: servo's presence on startup hangs sketch on: February 19, 2012, 12:21:57 pm
Hi,
    You definitely don't want one on the 5V, but it might be worth trying a 1K resistor on the signal wire.

Duane.
1571  Using Arduino / Programming Questions / Re: servo's presence on startup hangs sketch on: February 19, 2012, 11:17:37 am
Hi,
    This is worth a quick shot, connect the servo signal wire to Arduino through a resistor, try 330 Omhs, it may well not be the problem, but its one more thing you can easily eliminate.

    Sorry for asking this, but you have got a shared earth between the Arduino and Servo ?

Duane B.

rcarduino.blogspot.com
1572  Using Arduino / Motors, Mechanics, and Power / Re: New to Arduino question about motor control on: February 19, 2012, 10:21:06 am
Hi,
    This is the post I thought you might find relevant - basically using set zones within the throttle signal to trigger a mode change or initiate a preset sequence of actions, such as panning some turrets to a set point -

http://rcarduino.blogspot.com/2012/01/how-to-read-rc-receiver-with_25.html

Duane B

rcarduino.blogspot.com
1573  Using Arduino / Motors, Mechanics, and Power / Re: New to Arduino question about motor control on: February 19, 2012, 09:04:11 am
Hi,
   You can control many servos from a single Arduino, you can also modify servos for constant rotation in case you wanted to be able to rotate your turrets through more than a complete rotation. To do this all you will need is an external power source for the servos, I am assuming that you boat uses nimh, nicad or Lipo batteries like my cars do, in which case they will provide all of the power you need.

Have a look at my blog for lots of posts regarding reading from rc receivers, controlling servos and on that might be of particular interest to you regarding a cheat for adding extra channels.

Duane B

rcarduino.blogspot.com

1574  Using Arduino / Programming Questions / Re: servo's presence on startup hangs sketch on: February 19, 2012, 04:20:30 am
Hi,
   Have you tried using the servo with external power ? it might be that with all of your other hardware connected there is too much current draw during start up. The current demands of the hardware may be less after an initial draw at start up which is why your servo then works.

   Just an idea, but it should be easy for you to test with a 9v battery, just make sure that the servo has a common ground connection with you Arduino.

Duane B.

rcarduino.blogspot.com
1575  Using Arduino / Project Guidance / Re: Using ServoTimer2 and ServoDecode with 8MHz Arduino on: February 18, 2012, 01:34:27 pm
Hi,
    Are you reading the signal directly from the transmitter or from a port on the receiver ?
   
    As for the cars, you can have a lot of fun with a Tamiya M03, small, fast enough, tough to break, and simple enough that a child can help with some of the building.

See here for a few of my own M03's and some advice you won't ever get a hobby shop -
http://rcarduino.blogspot.com/2012/02/newbie-advice-and-new-take-on-everyday.html

Duane B.

rcarduino.blogspot.com
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