[LED] with external supply! Help

Hello guys, I'm doing a project for my room and I've a infrared (TSAL6200) which consumes 100mA (Arduino max output supply is 40mA per pin [or 300 mA total]), the question is, how do I external power supply it and send IR commands with arduino for it?

Thanks, Heitor.

You can use a transistor or MOSFET to "boost" the current. [u]Here is an example[/u] of a MOSFET driving a motor. (You'd need a current-limiting resistor and you can use your existing 5V power supply, and since you're not driving a motor you can leave-out the "protection diode" D1 .)

[u]Here's and example[/u] using a transistor to drive a solenoid.

Do you know how to calculate the current limiting resistor? You might try it at 30 or 40mA first. That might be enough. And during project development, it would be a good idea to try it at low power and short distance anyway.

...and send IR commands with arduino for it?

It's just like sending serial data (RS-232, etc.). You should be able to find some examples, but depending on what you're controlling you may have to capture/record transmissions from the existing transmitter in order to figure-out the codes.

If that is all you are doing, you can still use just the Arduino.

Use an NPN transistor as a switch. LED will have access to more current from the 5v line, and you will still control it just the same with the IO pin.

You want to send IR commands, presumable like an IR remote? Those have a carrier frequency of usually 38kHz, which is not trivial to achieve with Arduino. Looking at you question, you might have a long way in front of you.

ElCaron:
You want to send IR commands, presumable like an IR remote? Those have a carrier frequency of usually 38kHz, which is not trivial to achieve with Arduino. Looking at you question, you might have a long way in front of you.

What are you talking about?

DVDdoug:
You can use a transistor or MOSFET to "boost" the current. [u]Here is an example[/u] of a MOSFET driving a motor. (You'd need a current-limiting resistor and you can use your existing 5V power supply, and since you're not driving a motor you can leave-out the "protection diode" D1 .)

[u]Here's and example[/u] using a transistor to drive a solenoid.

Do you know how to calculate the current limiting resistor? You might try it at 30 or 40mA first. That might be enough. And during project development, it would be a good idea to try it at low power and short distance anyway.
It's just like sending serial data (RS-232, etc.). You should be able to find some examples, but depending on what you're controlling you may have to capture/record transmissions from the existing transmitter in order to figure-out the codes.

DVDdoug:
You can use a transistor or MOSFET to "boost" the current. [u]Here is an example[/u] of a MOSFET driving a motor. (You'd need a current-limiting resistor and you can use your existing 5V power supply, and since you're not driving a motor you can leave-out the "protection diode" D1 .)

[u]Here's and example[/u] using a transistor to drive a solenoid.

Do you know how to calculate the current limiting resistor? You might try it at 30 or 40mA first. That might be enough. And during project development, it would be a good idea to try it at low power and short distance anyway.
It's just like sending serial data (RS-232, etc.). You should be able to find some examples, but depending on what you're controlling you may have to capture/record transmissions from the existing transmitter in order to figure-out the codes.

Wow, this MOSFET thing is really confusing, I looked for it in google, I'm still confuse... And about sending IR codes, that's ok, I'm already sending codes to my TV (It's working fine but I want more power on led !!!)

The thing what I was thinking was: Use a 9v 2A supply to supply arduino and 2 rows ( + and - ) of breadboard, the arduino only consumes 1A, the excess would go to my breadboard which should supply a LCD (90mA) which have a simple conection (positive,negative, rx, tx pins) [positive and negative should direcly to external power [with resistors to get 5v]) and supply 4 IR LEDs (0,4A total) but the problem is how to do this LED power supply, the question is, MOSFET, I can only use it with Arduino 5v pin or can I use with an external power supply?

INTP:
If that is all you are doing, you can still use just the Arduino.

Use an NPN transistor as a switch. LED will have access to more current from the 5v line, and you will still control it just the same with the IO pin.

The problem is: I'll have a tons of sensors connected into my arduino, light sensor, rf emissor, rf receptor, presence sensor.................. They will use a good current, that's why I wanna supply the LED with an external supply

Did you say you were going to drop 9v down to 5v with just resistors?
Don't do that.
Either use a proper 5v power supply or get a proper voltage regulator.

INTP:
Did you say you were going to drop 9v down to 5v with just resistors?
Don't do that.
Either use a proper 5v power supply or get a proper voltage regulator.

OK, I can buy a 5v 2a supply, but I still doesn't know how to connect the LED properly...

Hbadotti:
The thing what I was thinking was: Use a 9v 2A supply to supply.

arduino and 2 rows ( + and - ) of breadboard, the arduino only consumes 1A,

the excess would go to my breadboard which should supply a LCD (90mA) which have a simple conection (positive,negative, rx, tx pins) [positive and negative should direcly to external power [with resistors to get 5v]) and supply 4 IR LEDs (0,4A total) but the problem is how to do this LED power supply, the question is, MOSFET, I can only use it with Arduino 5v pin or can I use with an external power supply?
The problem is: I’ll have a tons of sensors connected into my arduino, light sensor, rf emissor, rf receptor, presence sensor… They will use a good current, that’s why I wanna supply the LED with an external supply

  1. Good thinking.

  2. Wrong…I think.

  3. Lost here.

Use a 9volt/1Amp regulated supply with DC plug, and connect it to the DC socket.

The Arduino and sensors will run happily of that 9volt supply if the sensors don’t draw more than ~300mA.

Connect four IR LEDs and a 22ohm resistor in series between the V-in pin and the collector of a 2N2222 transistor. Emitter to ground. Base via a 470ohm resistor to the Arduino pin.
Leo…
IR LED Driver.png

INTP:
What are you talking about?

I am talking about the carrier frequency of common IR remotes, because he wants to send IR commands. What are you asking about?

Hbadotti:
Hello guys, I'm doing a project for my room and I've a infrared (TSAL6200) which consumes 100mA (Arduino max output supply is 40mA per pin [or 300 mA total]), the question is, how do I external power supply it and send IR commands with arduino for it?

Thanks, Heitor.

Note 100 mA is the max continuous current rating. Normal use would be much lower. Try around 50mA.

Weedpharma

weedpharma:
Note 100 mA is the max continuous current rating. Normal use would be much lower. Try around 50mA.

Weedpharma

Not if he wants any range at all on the IR led.

ElCaron:
I am talking about the carrier frequency of common IR remotes, because he wants to send IR commands. What are you asking about?

I'm talking about it being trivial, stupid easy, to send IR commands at those modulated protocols with an Arduino, so I have no idea what you're talking about when you think it's a difficult thing and this guy has a long road ahead of him or whatever fear mongering you were going on about.

ElCaron:
You want to send IR commands, presumable like an IR remote? Those have a carrier frequency of usually 38kHz, which is not trivial to achieve with Arduino.

Yes it is. You simply change the PWM frequency on one of the timers and you automatically have it.

weedpharma:
Note 100 mA is the max continuous current rating. Normal use would be much lower. Try around 50mA.

Weedpharma

It works with 40-30 mA, but I want full range of my LED

Wawa:

  1. Good thinking.

  2. Wrong…I think.

  3. Lost here.

Use a 9volt/1Amp regulated supply with DC plug, and connect it to the DC socket.

The Arduino and sensors will run happily of that 9volt supply if the sensors don’t draw more than ~300mA.

Connect four IR LEDs and a 22ohm resistor in series between the V-in pin and the collector of a 2N2222 transistor. Emitter to ground. Base via a 470ohm resistor to the Arduino pin.
Leo…
IR LED Driver.png

Ok, I got a little confuse when you said “The Arduino and sensors will run happily of that 9volt supply if the sensors don’t draw more than ~300mA.”, these 300mA is included with vin pin or only sensors which’s connected in arduino pins digital, analog and 5v/3.3v pin?

I mean, if I’ve a sensor of 250 mA on arduino 5v pin and have another sensor with 400mA in vin pin, my arduino will damage?

Hbadotti:
I mean, if I’ve a sensor of 250 mA on arduino 5v pin and have another sensor with 400mA in vin pin, my arduino will damage?

There is a reverse voltage protection diode between the DC socket and V-in.
The diode will drop ~0.7volt.
So 9volt on the DC socket gives (9volt - 0.7volt) = ~8.3volt on V-in.
The current capability of that diode is <=1Amp.

V-in goes to the onboard 5volt regulator that has to drop 8.3volt to 5volt.
Power (heat) in that regulator is the voltage it has to drop (8.3-5=3.3volt) times the current it has to supply.
The Arduino (Uno) takes ~55mA. The 5volt load you mentioned takes 250mA. 300mA total.
Power = (8.3 - 5) * 0.3Amp = ~1watt. I think the practical limit for the regulator on an Uno is about 1.5watt at normal room temp if not mounted inside a case. 1watt is a rather warm regulator, but still ok.

Total current through the reverse protection diode is 400mA + 300mA = 700mA, so still ok.

I think you got the 400mA from four strings of 100mA IR LED diodes.
Not needed. All LEDs in series is the same LED drive current, but less strain on the supply.
Do use IR transmitter code. Peak LED current with the values I gave you is about 130mA.
130mA is well within the pulse limit of those LEDs, but over the limit of continuous current.
Leo…

Wawa:
There is a reverse voltage protection diode between the DC socket and V-in.
The diode will drop ~0.7volt.
So 9volt on the DC socket gives (9volt - 0.7volt) = ~8.3volt on V-in.
The current capability of that diode is <=1Amp.

V-in goes to the onboard 5volt regulator that has to drop 8.3volt to 5volt.
Power (heat) in that regulator is the voltage it has to drop (8.3-5=3.3volt) times the current it has to supply.
The Arduino (Uno) takes ~55mA. The 5volt load you mentioned takes 250mA. 300mA total.
Power = (8.3 - 5) * 0.3Amp = ~1watt. I think the practical limit for the regulator on an Uno is about 1.5watt at normal room temp if not mounted inside a case. 1watt is a rather warm regulator, but still ok.

Total current through the reverse protection diode is 400mA + 300mA = 700mA, so still ok.

I think you got the 400mA from four strings of 100mA IR LED diodes.
Not needed. All LEDs in series is the same LED drive current, but less strain on the supply.
Do use IR transmitter code. Peak LED current with the values I gave you is about 130mA.
130mA is well within the pulse limit of those LEDs, but over the limit of continuous current.
Leo…

I really have to study about this, so, If I use this transistor (2N2222), I’ll 5v in V-Pin? With 400 mA?

Hbadotti:
If I use this transistor (2N2222), I'll 5v in V-Pin? With 400 mA?

That does not make sense (to me).

Just connect a 9volt regulated supply to the DC socket.
Then 8.3volt will be available on the V-in pin.

You can use that V-in pin (as power output) to power the string of LEDs.
The transistor switches the LEDs to ground in the rate of the remote signal.
Leo..

That does not make sense (to me)

Ditto.

Avoide the Vin pin for powering things, it does not have any advantages and only has drawbacks in that you limit the current available from your supply.

Grumpy_Mike:
Avoid the Vin pin for powering things...

The V-in pin provides a high enough voltage for a string of four IR LEDs when an external 9volt supply is used.
But you're right. It is also possible to use two strings of two LEDs with two 22ohm resistors, and power them from the 5volt pin. Then they also work when powered from USB.
Leo..