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Many of you are making your projects using this fabulous board linkit one board. I am not sure that you are aware of this fact or not but this linkit one digital as well as PWM pin have a very less current output. It is much much less than a arduino board. 2 led connected to its digital pin glow very dimly. So in this instructable I would be telling you how to increase the current output of linkit one board.

Step 1: Gather Parts

Here is the part list:

  • Linkit one
  • TIP31C
  • LEDs
  • Breadboard
  • Jump cables

Step 2: Making a Row of Led

A single led can be glow easily with a linkit one board. But multiple led will either not glow and if they will glow then very dimply. So we have to make a row of leds to check whether we are able to glow that row brightly thus succeeding in our purpose. I chose the two power rails of the breadboard to connect leds. The leds of first rail will be connected to the board using TIP31C and that of second rails directly to the board. Put at least four leds in each rails of the breadboard and proceed to next step.

Step 3: Connect TIP31C

Tip31C is a basic NPN transistor. It is used here to switch the current of the main power supply with the likit one digital pin's current. Make sure that it switches current not voltage. Current and volatage are different things. You can find this transistor very easily in the market. To connect it to your board, do the following things:

  • pin 1-----Linkit one digital pin 11
  • pin 2-----Led line gnd
  • pin 3-----Linkit one gnd

Connect the positive of first the rails to positive of linkit one board and positive of second rail to digital pin 5. Connect negative of second rail to gnd of the board.

Step 4: Upload the Code

Here is the code by which you can check the difference:

int led1=11;

int led2=5;

void setup()

{

pinMode(led1,OUTPUT);

pinMode(led2,OUTPUT);

digitalWrite(led1,HIGH);

digitalWrite(led2,HIGH);

}

void loop()

{
}

Step 5: END

Now you would be able to see the difference between the two rows of led. The first row would be glowing brightly and the second will be glowing dimly. This thing also works with PWM so you can also use it with PWM projects. Hope you like the instructable. For any query comment below.

<p>I don't see any resistor. Do you want to destroy your output ?</p>
There is no need of using resistor because output of linkit one is 3.7v. Its not like arduino whose output is 5v.
<p>It's not a question of voltage but current. Your MCU output is connected to the transistor base without limiting resistor, this is like putting a diode directly on the output.</p>

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