First of all, thanks for taking the time to read this! I'm completely new to this and need some guidance.
I have a maxbotix EZ1 sonar, arduino uno with prototype shield, and 7 small .13 amp brushless motors. I want to set the sonar sensor up so that when a person walks up the fans turn on and when they walk away the fans turn off. I hope this sounds simple. I don't see very many projects using this many motors, do I need a relay board or a mosfet? This is the fan i'm working with- http://www.ebay.com/itm/Brushless-DC-Cooling-Blower-Fan-40-x-40-x-20mm-4020-12V-/251077716166
Yes either a relay or a MOSFET will do it. 12V, 1A supply is needed (perhaps a bit more
than 1A to allow for switch-on current being somewhat higher, 1.5A ?)
Assume you just want to parallel all the fans and switch them together?
I am not sure about needed any flyback diodes, since these motors have a built-in
control chip that presumably does this already.
Hi, although it might sound trivial but if I was starting 7 fans I would split them into a bank of 4 and a bank of 3.
Then turn the bank of 4 ON first then 0.25 or .5 of a second later start the bank of 3, these brushless fans can be hungry when starting and can be quite a demand on power at start up.
MOSFET switching should be fine.
You guys are awesome. Would it be hard to separate all of them in there own bank so that the first turns on (.25 sec. later) the second one turns on and so on? You think I could use a series circuit without much trouble?
also here is a modified code I used to make it work from the arduino examples!
/*
Conditionals - If statement
This example demonstrates the use of if() statements.
It reads the state of a potentiometer (an analog input) and turns on an LED
only if the LED goes above a certain threshold level. It prints the analog value
regardless of the level.
The circuit:
potentiometer connected to analog pin 0.
Center pin of the potentiometer goes to the analog pin.
side pins of the potentiometer go to +5V and ground
LED connected from digital pin 13 to ground
Note: On most Arduino boards, there is already an LED on the board
connected to pin 13, so you don't need any extra components for this example.
created 17 Jan 2009
modified 9 Apr 2012
by Tom Igoe
This example code is in the public domain.
*/
// These constants won't change:
const int analogPin = A1; // pin that the sensor is attached to
const int FAN = 4; // pin that the LED is attached to
const int threshold = 50; // an arbitrary threshold level that's in the range of the analog input
void setup() {
// initialize the LED pin as an output:
pinMode(FAN, OUTPUT);
// initialize serial communications:
Serial.begin(9600);
}
void loop() {
// read the value of the potentiometer:
int analogValue = analogRead(analogPin);
// if the analog value is high enough, turn on the LED:
if (analogValue > threshold) {
digitalWrite(FAN, LOW);
}
else {
digitalWrite(FAN,HIGH);
}
// print the analog value:
Serial.println(analogValue);
delay(1); // delay in between reads for stability
}
