Hi,

To save myself from typing I have added two relevant links to my signature. Read the first one and watch the second one.

If your project is going to be a big one, you will need a better regulator than the 7805, its good for an amp, you might need several amps as your project grows.

Duane B

Hi,

One last question to eliminate power, you do not mention how your servos are powered, are they also on separate power ? If not the addition of the motor shield the components of which take some power from the arduino maybe just enough to take it over the edge.

Duane b

rcarduino.blogspot.com

hi,

Are you sure it's the interrupt not a power issue ? The effect would look similar in your case.

Have a read of this

http://rcarduino.blogspot.com/2012/04/servo-problems-with-arduino-part-1.html

Then watch this, it's about servos, but the same applies to motors

http://rcarduino.blogspot.com/2012/04/servo-problems-part-2-demonstration.html

Duane B

rcarduino.blogspot.com

or, don't take anything apart, don't reinvent the wheel and just do it this way -

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

Duane B

rcarduino.blogspot.com

Everything in Arduino can have at least one viable answer apart from - is Arduino object orientated ?

Duane B

Hi,


Read this

http://rcarduino.blogspot.com/2012/04/servo-problems-with-arduino-part-1.html

Then watch this

http://rcarduino.blogspot.com/2012/04/servo-problems-part-2-demonstration.html

Then get the batteries.

If there is anything that you don't understand, I would be interested to know what it is, I think I have everything covered, but maybe not.

Duane B

rcarduino.blogspot.com

Hi,

I think this is a nice reference to have around, its the guide that oomlout supply with thier Arduino kits -

http://oomlout.com/products/ARDX/ARDX-experimenters-guide-WEB.pdf

Duane B

rcarduino.blogspot.com

Hi,
   Let us know if the power circuit resolves your problem, I think it will, your external power is still limited by the Arduino onboard regulator and may not have such a high current capacity in the first place.

Duane B

The investment on day one is inversely proportional to the chance of the project ever getting finished.

ie.

I bought ten servos XYZ sensors, a Mega and four brushless speed controllers. I need help getting my project to work.

Hi,
   Your recommending a sensor that you cant get to work ?

   You can buy very low cost emitters and detectors, to detect black you want to emitter and detector, to detect ambient, you dont need the emitter.

see here for one example -

http://proto-pic.co.uk/infrared-emitters-and-detectors-pair/

Duane B

rcarduino.blogspot.com

Hi,
   This is probably a power problem,

see here and here for why and how to fix it -

http://rcarduino.blogspot.com/2012/04/servo-problems-part-2-demonstration.html

and how to fix it -

http://rcarduino.blogspot.com/2012/04/servo-problems-with-arduino-part-1.html

Duane B

rcarduino.blogspot.com

Hi,
   Its likely that you circuit does not have enough power, watch this, its what is happening to your Arduino -

http://rcarduino.blogspot.com/2012/04/servo-problems-part-2-demonstration.html

This will also give you some background, it applies to servos but the approach to power is just as relevant to motors -

http://rcarduino.blogspot.com/2012/04/servo-problems-with-arduino-part-1.html

Duane B

rcarduino.blogspot.com

Hi,
   Not really. I assume the 7.4V batteries are NIMH or LIPO, if so its a really good starting point, what is the mah rating its usually a number in the 1000's written all over the battery ?

In an ideal situation you would have two circuits, one is the 5V logic circuit, the other is a power circuit which in the case of servos can be 4.8 to 6 volts - don't try and power the Servos directly from the 7.4 it could damage them.

Looking at the Ardumotor, it takes the motor power from the VIN of the Arduino, this is before the Arduino on board regulator so is not current limited by the regulator. The Ardumotor take logic power for the onboard circuits from the Arduino 5V, this is after the regulator so not going to deliver the amps you need for the Servos.

The voltage coming from vin will be too high for the servos so dont use this directly.

One quick solution is to pick up a regulator of the type used in RC Models, these are able to deliver 5 or 6 volts from a 7.4 volt battery and will also give you 2 amps or more for your servos.

This will allow you to use a single high capacity NIMH or LIPO to drive your project, connect the servos to the battery through the regulator suggested above and keep everything else as you currently have it.



Duane B

rcarduino.blogspot.com

On the positive side, many members strike a commendable balance between giving the answer and giving the information to find the answer. In the short time that I have been around the forum I have never seen it formalised anywhere, it just seems to be the spirit of the forum, its great, keep it up.

Duane B

Thanks,
    I really need to settle down and just work on the LapTimer and the Traction control. I was waiting for some components but have then now so no more excuses - apart from being in Lebanon and my kit is all in Dubai.

Duane B

rcarduino.blogspot.com