Show Posts
Pages: [1]
1  Using Arduino / Project Guidance / Re: Newbie Needs help!!! on: April 09, 2013, 12:41:32 pm
Have a look at this thread from yesterday. It seems to need some work still, but should be adaptable to use a Hall sensor.

It will give you the rpm, which you can convert to speed. Then the difference between two successive speed measurements, and the time between them, will let you get the deceleration....


Thank you for the reference. I am having a bit of trouble making sense of all of the programming and lingo that is taking place on that forum, but it will be useful, I'm sure! This is the programming I came up with when I was thinking of using a reed sensor. I have not completed it because I simply got lost and was not sure what to do next... Maybe you have some advice?

Code:
//calculations
//tire radius ~ 7 inches
//circumference = 2*pi*r=~43.6 inches
//max speed of 5mph=~88inches/second
//max rps=~2

#define reed A0//pin connected to reed sensor

//storage variables
int reedVal;
long timer;// time between one full rotation
float mph;
float radius = 7;// tire radius (in inches)
float circumference;

int maxReedCounter = 100;//min time of one rotation (for debouncing)
int reedCounter;

void setup(){
 
  reedCounter = maxReedCounter;
  circumference = 2*3.14*radius
  pinMode(reed, INPUT);
2  Using Arduino / Project Guidance / Re: Newbie Needs help!!! on: April 09, 2013, 12:37:43 pm
From 5mph, it may be stopping so quickly that you'll need multiple magnets on the wheel to establish the deceleration in tim to light the leds.

How would you go about telling the Arduino that there are multiple spots being measured?

If a MIDI keyboard can measure key velocity, why not a brake pedal?
Surely you want to know the intent, not the outcome, which could depend on other factors like recipient ad surface condition.

That's a very good point. How would you go about doing this if you were just to measure the pressure in the brake pedal?
3  Using Arduino / Project Guidance / Re: Newbie Needs help!!! on: April 09, 2013, 12:09:59 pm
2rps not 20
Thanks! Looking back, I'm not sure how I even managed that mistake!!
4  Using Arduino / Project Guidance / Re: Newbie Needs help!!! on: April 09, 2013, 12:08:53 pm
I had a similar thought in the beginning, but since in real life brake pedals wear out and sensitivity is different from car to car it seems more realistic to use the actual rate of deceleration to decide how many LEDs would be illuminated.
5  Using Arduino / Project Guidance / Re: Newbie Needs help!!! on: April 09, 2013, 12:00:46 pm
//tire radius ~ 7 inches
//circumference = 2*pi*r=~43.6 inches
//max speed of 5mph=~88inches/second
//max rps=~19.8


I am more or less trying to make a brake light that will illuminate the brake lights with more intensity if the brakes are slammed. I have an idea, but just cannot figure out how to do the programming!
6  Using Arduino / Project Guidance / Re: Newbie Needs help!!! on: April 09, 2013, 11:50:11 am
The wheel is literally the wheels to a power wheels childrens toy and it will be going as fast as 5MPH
7  Using Arduino / Project Guidance / Newbie Needs help!!! on: April 09, 2013, 11:41:50 am
Hello Arduino world!

I am trying to do a project and failing miserably in the Arduino aspects! I would like to have LEDs be controlled by how quickly an object is decelerating. I was hoping to use a hall effect sensor to measure the speed by having the sensor toggle every time a magnet did a full rotation on the wheel. Could anyone help me with where to begin and go with this?

Thanks so much!
8  Using Arduino / Project Guidance / Re: LEDs controlled by speed-- Programming help!! on: April 04, 2013, 09:31:28 pm
I guess a better question would be how to increase the power to an Arduino Uno? My understanding is an 6volt (or whatever power source) to the LEDs to a resistor and then a transistor. That would then be connected to the pin on the Arduino board and then to ground? Would this solve my abilities to power more than one LED or should I be able to do it without the external power source?
9  Using Arduino / Project Guidance / Re: LEDs controlled by speed-- Programming help!! on: April 04, 2013, 08:51:18 pm
Success! To do a fade with many LEDs do you suggest parallel over series? If I want them to fade at different levels should I program it to different pins and then have them dependent off of if statements?
10  Using Arduino / Project Guidance / Re: LEDs controlled by speed-- Programming help!! on: April 04, 2013, 07:56:28 pm
I apologize that it came off that way! I do want to learn and understand this programming, I simply need to learn as much as I can through this programming rather than learning properly through all of the tutorials since I have less time that could be desired for a newbie!

That link you provided is very helpful, thank you!

When you said PWM is that comparable to 'fading'? I was under the impression to use an AnalogWrite for that function rather than a DigitalWrite. Would you advise one being better than the other?

Again, I really appreciate you responding and any advice you could give! Thank you!
11  Using Arduino / Project Guidance / LEDs controlled by speed-- Programming help!! on: April 03, 2013, 07:32:58 pm
Hello,

I am working on a project that will allow LEDs to represent brake lights. I would like the LEDs to light up dependent on how quickly the car is slowing down. The LEDs would light up in a vertical ascending pattern. Light deceleration would illuminate the first strand of LEDs, medium deceleration would illuminate the first and second strand of LEDs, and hard braking would illuminate all three strands of braking. If it is possible I would also like to have the third strand of LEDs flash after all three strands have been lite if the brakes were to be slammed.

I intend to calculate speed using a hall effect sensor or optical sensor and have them measure the circumference of the wheel of the car (in this sense a power wheels kids toy). I had wanted to use an accelerometer, but was having trouble finding an affordable one that would measure such small increases and decreases in speed since the power wheels only goes 5 miles an hour.

I am having a lot of trouble with the programming, could anyone help me out?? This is my first time trying to do any programming and I am under time constraints so cannot spend too much time learning all of Arduinos functions.

Thank you!!!
Pages: [1]