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46  Using Arduino / Project Guidance / Re: RC Traction control - accurately measuring wheel speed on: June 09, 2013, 04:28:25 am
This week I will try to get some long exposure pictures of this system running at night to that I can see a trace of the traction situation before testing any control algorithms, for now, here is a draft update on the RCArduino traction control project

Duane B
47  Using Arduino / Project Guidance / Re: PWM in on: June 09, 2013, 02:01:38 am
I have managed to use Duane's code, together with GPS to make an autonomous vehicle navigate to a waypoint.
It was very smooth and easy to understand his code before I got to it...
I can take over control at any time by turning on the transmitter.

Got a video ? I will put a link to your project on the blog if thats ok ?

Duane B
48  Products / Arduino Due / Re: Due controlling ESC with PWM. on: June 09, 2013, 02:00:16 am
Why not just use the servo library, its standard, well supported, means you can port code from the 8-bit Arduino's etc ?

This example outputs 8 servo signals and reads them back in using interrupts -

Duane B
49  Using Arduino / Project Guidance / Re: PWM in on: June 09, 2013, 01:52:12 am

   Start here -

   Once you can read the incoming pulse width using the code above, you can add an if statement to turn your camera on and off, but the starting point is the code in the post above - or you could use the dreaded pulseIn function

Duane B
50  Using Arduino / Audio / Re: Groovesizer: auduino with 16-step sequencer on: June 08, 2013, 04:39:45 am

You have almost certainly wired the Pots incorrectly, can you post a diagram of what you think you have done and a picture of how you have done it.

Duane B
51  Using Arduino / Project Guidance / Re: Outdoor IR Beam trigger Issues on: May 27, 2013, 12:42:31 am
This uses a simple IR LED and IR Receiver, it works very well at high speed in the Dubai sunshine.

The key to getting this working was -

1) Spray paint the inside of the receiver enclosure with 'ultra flat' non reflective camouflage paint

2) Fix the received so that it is an inch back from the small opening in the enclosure

This ensures that only direct light is able to reach receiver, all indirect light is absorbed by the non reflective pain before it can reach the detector.

You can find details of all the components etc by following the other posts in the build along.

Duane B
52  Using Arduino / Project Guidance / Re: Slotcar speed controller with display and electronic memory project on: May 20, 2013, 07:50:50 am
   One way of keeping the weight low - as in low down where it helps rather than high up where it does not - is to use PCB as the chassis material. Lot of guys have done this in the past becuase its easy to solder home made chassis together this way. With a bit of though you could design an Arduino chassis.

Lots of examples here -

Duane B
53  Using Arduino / Audio / Re: Bandlimited waveform generation on: May 13, 2013, 03:01:30 am
If your already using a wavetable for your sinewave, why not use it in the calculation as well, thats going to be a lot faster.

If you really wanted to generate a band limited squarewave, you could do the calculation in loop and flag your ISR when the wavetable is ready this way you get what you want reasonably quickly without messing up the audio generation.

Alternativley I have seen that wave shaping can acheive the same result with less computation however I have not yet been able to understand this approach

Duane B
54  Using Arduino / Audio / Re: DDS Lookup table length on: May 13, 2013, 02:57:05 am
I disagree a bit - if your output is 8-bit there is not much point in having higher resolution wavetables.

I assume that you want more than one output channel so even your 8 bit samples end up being around 6 bit resolution by the time they are down shifted into the output resolution.

If you have 12 bit or 16 bit output then yes it makes sense to have longer more detailed wavetables or to interpolate between samples in your tables, but with 8 bits, 256 is optimum.

Duane B
55  Using Arduino / Sensors / Re: How to read a pulse train asynchronously on: May 08, 2013, 12:37:48 pm
Have a look at 'input capture' or turn the interrupt off as soon as you have a reading, process the reading and then turn interrupts back on

Duane B
56  Using Arduino / Sensors / Re: How to read a pulse train asynchronously on: May 08, 2013, 11:18:02 am
Try this -

Duane B

57  Using Arduino / Programming Questions / Re: How can I control the speed of my servos?? on: May 08, 2013, 11:08:52 am
8 != 3

Duane B
58  Using Arduino / Motors, Mechanics, and Power / Re: Changing Servo library frequency? on: May 08, 2013, 05:48:29 am

First you need to choose your pins, look up the attachInterrupt function and let us know which pins can be used on the mega, it is then very easy to modify this code, but first let us know what you have found out about the pins -

Duane B
59  Using Arduino / General Electronics / Re: DAC in arduino DUE on: May 06, 2013, 11:10:52 am
Your not going to get from 2.7 volts to 3.9 volts with just a resistor for help.

Why do you think an op amp is not going to change value when you ask it to ?

Duane B
60  Using Arduino / Motors, Mechanics, and Power / Re: Servo not centering at 90° - after calibration on: May 06, 2013, 10:23:05 am
From memory, the internal tick size of the servo library is 4us so 1000 to 2000 us pulsewidth gives 255 steps even when using writemicroseconds.

As for the calibration i would use the map function with a separate mapping for 1000 to center and center to 2000. If you manually figure out what the center is, you should be good with this approach

Duane B
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