Show Posts
Pages: [1] 2 3 ... 17
1  Using Arduino / Sensors / Re: Reading car OEM pressure sensor on: May 20, 2014, 03:03:52 am
I actually got it sorted with a 100ohm resistor and it is working beautifully.

Thanks for your help, much appreciated. I may come back to you for power supply stuff smiley

Actually I've bought a couple of ready made switching regulator from ebay. As soon as they arrive I will test them.

Thank you.
2  Using Arduino / Sensors / Re: Reading car OEM pressure sensor on: May 16, 2014, 10:01:33 am
Anyone?
3  Using Arduino / Sensors / Re: Reading car OEM pressure sensor on: May 14, 2014, 12:48:33 pm
I've tested the sensor on the bench with a clean power supply.

Issue #1 doesn't exists on the bench, no erratic readings.

Issue #2 however still exists, when the output of the sensor is connected to the Arduino we read 3 volts. When I connect my voltmeter also we read 2.2 volts both on the voltmeter and the Arduino, which is correct. I then disconnected the voltmeter and put a 100ohm resistor from GND to the analog input and that corrects the readings. Is this correct what I've done?

Thanks.
4  Using Arduino / Sensors / Re: Reading car OEM pressure sensor on: May 11, 2014, 09:28:52 am
Did some tests. Actually the voltage regulator closest to the jack on the Arduino doesn't get nearly as hot as the actual L7809 regulator!

So I measured the current between the output of the L7809 and the Arduino when nothing is connected to the board. This is about 76mA (0.076A). And the regulator outputs about 8.87v. So from my calculations at room temperature of about 20'C the voltage regulator gets to around 53'C!

With an LCD connected (from 4d systems) to the board, then the current increases to 100mA (0.1A). So at room temperature of around 20'C the voltage regulator gets hot at around 64'C.

Best is to use a switching regulator rather than a voltage regulator?
5  Using Arduino / Sensors / Re: Reading car OEM pressure sensor on: May 09, 2014, 04:19:58 am
Thanks again. I shall do some extensive tests and see what's what. I may even try and remove the sensor from the car and power it up with a clean power supply to see if it's the car environment or not.

While we're talking about the voltage regulators etc. I use the output from the voltage regulator mentioned and connect to the jack of the Arduino to power it up. This makes the voltage regulator closest to the jack super hot. To avoid this is it better to power the Arduino via the VIN pin with an L7805 instead?

Thank you.
6  Using Arduino / Sensors / Re: Reading car OEM pressure sensor on: May 08, 2014, 08:47:46 am
Thank you ever so much for the advice. I will for sure connect to the 'scope and check.

Something else came to my mind; I use an L7809 voltage regulator to power up the Arduino in the car. I use a diode for reverse polarity on the input pin and a ceramic 100nF capacitor on the ground pin and the voltage output. Do you think this could be my issue with having noise on the Arduino side? Or Arduino has enough capacitors etc to make the readings on analog input pins clean?

Thanks.
7  Using Arduino / Sensors / Re: Reading car OEM pressure sensor on: May 08, 2014, 04:03:46 am
Have you got your grounds connected appropriately ?

Yes, grounds are connected appropriately.
8  Using Arduino / Sensors / Re: Reading car OEM pressure sensor on: May 08, 2014, 04:03:13 am
Have you looked at the output on an oscilloscope?  It's possible the output is PWM and your integrating voltmeter is showing you the waveform average, but your ADC is reading high or low values or somewhere in between, depending on the when the SAH takes its snapshot.

I haven't tested with an oscilloscope, but I am 100% sure the output from the sensor is analog output.
9  Using Arduino / Sensors / Reading car OEM pressure sensor on: May 07, 2014, 02:47:12 pm
Hi everyone,

I am trying to read the signal output out of the stock turbo (boost) pressure sensor, which is also connected to a stock analog boost gauge that came with my car.

The sensor is a 3 wire sensor; 12v supply, ground and signal output. The signal output varies from 0-5 volts. I know what voltage corresponds to what pressure reading so that's fine.

For example when there is power to the sensor the analog gauge reads 0 PSI and voltmeter reads 2.3 volts.

The issues are as follows:

1) With the gauge connected to the sensor, I try to also read the signal output from the sensor with an Arduino analog input pin, the readings however are very erratic. They jump from 2.3 volts to 3.3 volts erratically and not stable at all.

Voltmeter reads the voltage as a stable voltage of 2.3 volts.

2) When I disconnect the gauge completely and apply power to the sensor it really should read 2.3 volts at 0 PSI but it reads more like 3.5 volts, that's about 1 volts more! This measurement is taken using my voltmeter.

Any ideas on first of all  how to rectify the erratic readings and then any ideas why the voltage doesn't read correctly without the gauge connected?

Any help is much appreciated.

Thanks.
10  Using Arduino / Microcontrollers / Arduino Mega 2560 Driver Install Change Name on: November 24, 2013, 04:51:44 pm
Hi everyone.

On Windows  7 for example,  when for the first time one plugs their Mega 2560 board to their computer a little pop up appears telling you that it's installing  the drivers.

On this pop up it says "Arduino Mega 2560", can this be changed at all? Maybe by burning the bootloader to the board again?

Any help is appreciated.

Thanks.
11  Using Arduino / Motors, Mechanics, and Power / Re: EasyDriver stepper motor driver not fast on: September 17, 2013, 09:26:24 am
Anybody?
12  Using Arduino / Motors, Mechanics, and Power / Re: EasyDriver stepper motor driver not fast on: September 12, 2013, 01:51:31 am
Yes you're right, I was typing in a hurry.

The Easydriver board is powered with the Arduino via +5v and GND pins. No power to the PWR IN pins. I've tried the same code with a power supply via PWR IN pins but the stepper motor doesn't move at all.
13  Using Arduino / Motors, Mechanics, and Power / Re: EasyDriver stepper motor driver not fast on: September 11, 2013, 09:48:08 am
Yes the clip is what the code does. It's working fine but I need it to go faster.

The wiring diagram is exactly like in this link:http://bildr.org/2011/06/easydriver/

I'm going to try it with a12v PSU to see what happens.
14  Using Arduino / Motors, Mechanics, and Power / Re: EasyDriver stepper motor driver not fast on: September 11, 2013, 04:23:49 am
Here is a clip of it on the cluster. It goee about 270 degrees.

https://www.youtube.com/watch?v=hrXkIfIyvt8&feature=youtube_gdata_player

It's only getting power from the arduino.

It's a car stepper motor so theoretically should go pretty fast. I haven't got much info on it.

I've tried longer periods of up to 5 seconds without any luck.

Thanks.
15  Using Arduino / Motors, Mechanics, and Power / EasyDriver stepper motor driver not fast on: September 11, 2013, 12:48:36 am
Hi.

I have been using the bildr's tutorial for Easydriver stepper motor driver to run a stepper motor on my car cluster.

bildr.org/2011/06/easydriver/

It works fine to go back and forth but only at speeds of up to 0.3. For example:   rotate(4200, 0.3);

If I make it any faster "rotate(4200, 1);" , you can see that it tries to move but it doesn't at all! I need it to move as fast as possible. Is there any solutions at all?

Here is the code:

Code:
#define DIR_PIN 2
#define STEP_PIN 3

void setup() {

  pinMode(DIR_PIN, OUTPUT);
  pinMode(STEP_PIN, OUTPUT);
}

void loop(){

  //rotate a specific number of microsteps (8 microsteps per step)
  //a 200 step stepper would take 1600 micro steps for one full revolution
  rotate(1600, 1); //reverse
  delay(1000);

  rotate(1600, 1);
  delay(1000);
}



void rotate(int steps, float speed){
  //rotate a specific number of microsteps (8 microsteps per step) - (negitive for reverse movement)
  //speed is any number from .01 -> 1 with 1 being fastest - Slower is stronger
  int dir = (steps > 0)? HIGH:LOW;
  steps = abs(steps);

  digitalWrite(DIR_PIN,dir);

  float usDelay = (1/speed) * 70;

  for(int i=0; i < steps; i++){
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(usDelay);

    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(usDelay);
  }
}

void rotateDeg(float deg, float speed){
  //rotate a specific number of degrees (negitive for reverse movement)
  //speed is any number from .01 -> 1 with 1 being fastest - Slower is stronger
  int dir = (deg > 0)? HIGH:LOW;
  digitalWrite(DIR_PIN,dir);

  int steps = abs(deg)*(1/0.225);
  float usDelay = (1/speed) * 70;

  for(int i=0; i < steps; i++){
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(usDelay);

    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(usDelay);
  }
}
Pages: [1] 2 3 ... 17