Push button to control RGB ledstrip

Projects General Guidance
1

I am having trouble connecting a push button to my arduino nano without it interfering with my power supplie. The project is very simple. While I push the button, the RGB led strip turns on and when I release the button the led turns off. It all works fine while plugged in my laptop but when I connect it to a 9V battery via the VIN and GND the led strips never turns off and I cant figure out where to connect the button for it to work properly. Here is the code and a schematic of my circuit I took from this website https://www.instructables.com/Driving-RGB-LED-strips-off-an-Arduino/#discuss

my button is currently plugged into D7 and the ground next to the VIN

int bLed = 9;
int gLed = 10;
int rLed = 11;

int buttonPin = 7;
int buttonVal;

int dt = 800;

void setup() {

  pinMode(buttonPin, INPUT);

  pinMode(bLed, OUTPUT);
  pinMode(gLed, OUTPUT);
  pinMode(bLed, OUTPUT);

  digitalWrite(buttonPin, HIGH);

  Serial.begin(9600);

}

void loop() {

  buttonVal = digitalRead(buttonPin);

  while (buttonVal == 1) {

    buttonVal = digitalRead(buttonPin);

    analogWrite(bLed, 255);
    analogWrite(gLed, 255);
    analogWrite(rLed, 255);

    Serial.println(buttonVal);

  }

  analogWrite(bLed, 0);
  analogWrite(gLed, 0);
  analogWrite(rLed, 0);

  Serial.println(buttonVal);


}

Screenshot_136
Screenshot_1361368×890 203 KB

2

How is the switch wired ?

1 Like
3

Instructables are crap. Never use then unless you know more that the author and can spot his mistakes.

Can you show a photograph of how you have wired the button in the circuit. I bet it is not like you described, it looks like it is putting a short across the power supply.

4

arduino 1
arduino 11920×2560 227 KB

5

arduino 2
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6

That is very odd. I hope the 9V battery is not the small PP3 type used in fire alarms, they can’t supply enough current.

Check your wiring again.

1 Like
7

it is wired to the ground next to the VIN and D7

arduino 2
arduino 21920×2560 382 KB

8

Try:

pinMode(buttonPin, INPUT_PULLUP);

Wires should be soldered to terminals.

2 Likes
9

thx for the tip I tried using INPUT_PULLUP but I still have the same problem, it works very well when plugged into my laptop via the micro USB then when I disconnect it and plug in my 9V battery it turns on when I push the button and never turns off

10

As mentioned the battery should not be a PP3 type.

Print the value of the state read from the switch.

Measure your voltages with a DMM.

1 Like
11

Unfortunately, I do not have a DMM, when I print the value they come out right but the arduino is plugged into the serial port of the computer. as soon as I disconnect it, it stops working properly. Do you think I should consider connecting a pull up resistor ?

12

Assume you are using a MOSFET, what is the part number ?

A MOSFET gate should have a 10k gate resistor to GND.

13

Screenshot_137
Screenshot_137722×863 169 KB

14

Your switch should be wired as S3 in the schematic offered to you.

You should have changed the code to INPUT_PULLUP.

You should look for a LOW when the switch is closed.

1 Like
15

An IRFZ44 is not the MOSFET that you should be using.

You should use a logic level MOSFET like IRLZ44.

Your MOSFET should be similar to the circuit, the motor and kickback diode would be replaced by your LED strip.

MOSFET_low_side_driver
MOSFET_low_side_driver666×528 3.58 KB

1 Like
16

I made a mistake, I am actually using logic level IRLZ44 , I looked up the wrong data sheet. I am trying to add a pull-up resistor like shown on the schematic you offered but I am having trouble. the S3 circuit only includes a single LED so I am unsure of how to hook it up. I tried my best to wire it properly but I cant seem to figure it out. My guess is that the problem comes from the wiring of the button and not the program nor the transistor but I could be wrong, I dont have alot of experience with this.

17

2022-01-12_16-17-27
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18

My guess is that you have got the wiring to to power wrong. There is no reason why this should not work when powered by a battery, unless it is not wired correctly.
You did not answer about the type of 9V battery you have. Please tell us.

19

Frankly, just don't use "Vin". :grimacing:

Use a 5 V power supply - a USB "phone charger" is generally inexpensive and available. If you connect it to the USB port, that will be exactly the same as powering it from the laptop, but a better way is to connect the regulated 5 V to the "Vcc" pin (and of course, ground).

What is most peculiar is your reluctance to confess what it is you actually mean by a "9V battery"! :roll_eyes:

1 Like
20

I am was using a pp3 9V battery but I realise this wasnt an appropriated power source. Although by using the Vcc Pin it seems to work just fine :slight_smile: !! thanks for the help, I will use a usb charger like recommended.