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Topic: Decoding Radio Control signal pulses (Read 35 times) previous topic - next topic

ardudillo

Very nice tool thanks a lot. One quick question, in the first post you 're talking about "an RC receiver that provides access to the pulse stream". What manner of beast is this? I 've played a bit with RC at various stages and I don't think I 'ever seen a receiver that offered anything except a normal servo plug for each channel. Is it a feature that I perhaps have missed? Do most manufacturers make them? How do I go about getting one? What do I ask for?

mem

dakkar, sorry I missed your post, I hope my reply is not too late.

> I really didnt think that a 1 volt power differential would make a difference, clearly I was wrong.  
Did you have the receiver ground connected to Arduino ground?
Powering the receiver from the Arduino volt supply is best because this ensures that the voltage on the Arduino pins is not too high.

>In my research I noticed people putting a 220ohm resistor in (the input), Is that necessary?
No but its no bad thing. Although all the receivers I have looked at drive the servo outputs at a logic level suitable for direct connect to arduino, using a resistor provides an additional degree of protection.

>I am also using a 10k pull-up per the suggestion and in both cases  
A pull-up should not be required in this application but the Arduino internal pull-up value is high enough that it should not be a problem if you have this enabled.

mem

#102
Dec 31, 2009, 04:36 am Last Edit: Dec 31, 2009, 04:39 am by mem Reason: 1
ardudillo, I have never seen a receiver that provided this signal out of the box. The thread  suggests a number that can be modified by soldering a wire onto the receiver circuit board.

This post mentions one that is cheap and easy to modify: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1248474405/13#13

Here is another receiver that has been discussed in earlier posts : http://www3.towerhobbies.com/cgi-bin/WTI0001P?I=LXGZT0&P=8

Heyarnold

I have this library working with my VEX controller now and was hoping to use it to contol motors with an H-Bridge.  

How would I create a PWM singnal for the H-Bridge?  

I tried using the ServoTimer2 library (it works very well too!) but it isn't suitable PWM for an H-bridge.   Any way to modifiy the ServoTimer2 library to do what I want?    Ideally, I would like to contol both servo motors and H-bridge together. :)

mem

Heyarnold, you control PWM for things like an H-Bridge using the standard arduino analogWrite function. Bear in mind that the decode library uses timer1 and  servoTimer2 uses timer2 so you only have pins 5 & 6 available for analogWrite on a standard Arduino board.

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