user8126: I'm making a project and i'm trying to send bits from an Arduino to another Arduino with the digital pins. So my setup are 2 Arduino's connected with a jumper.
I connected the grounds and they have both a different power supply.
Now I tried this set-up and as soon as I connect the output pin to the input pin from the other Arduino the voltage lowers from 5V to 2.6V so we can't detect our bits.
Anybody an idea how to solve this problem?
Thanks in advance!
Kind regards,
Manu

user8076: As Harry mentioned better to use some communication lines like UART or I2C or SPI.
If you dont have them available then use digital i/os but make sure their pull up and pull down resistors are correctly configured. If it is input just set as pull up and for output set as output pin. 
Regards,
Pathik

user8075: As you are trying to communicate with two arduinos I will suggest you to use some sort of standard communication protocol such as Two wire interface or I2c. There is the Wire.h library you can use and it has also a reference on the main Arduino site. If you have different necessity and want to carry on with you're methods you need to specify in more depth the connections you have made. As for now I can guess that the output is being connected to ground or some sort of load and that might be the reason you are seeing a drop out of voltage. But it might be also the case that you're output pin is changing so fast that the multimeter is not capable of reading the high state correctly

8126: <p>I'm making a project and i'm trying to send bits from an Arduino to another Arduino with the digital pins. So my setup are 2 Arduino's connected with a jumper.
I connected the grounds and they have both a different power supply.
Now I tried this set-up and as soon as I connect the output pin to the input pin from the other Arduino the voltage lowers from 5V to 2.6V so we can't detect our bits.
Anybody an idea how to solve this problem?</p>

<p>Thanks in advance!</p>

<p>Kind regards,
Manu</p>
 8076: <p>As Harry mentioned better to use some communication lines like UART or I2C or SPI.
If you dont have them available then use digital i/os but make sure their pull up and pull down resistors are correctly configured. If it is input just set as pull up and for output set as output pin. 
Regards,
Pathik</p>
 8075: <p>As you are trying to communicate with two arduinos I will suggest you to use some sort of standard communication protocol such as Two wire interface or I2c. There is the Wire.h library you can use and it has also a reference on the main Arduino site. If you have different necessity and want to carry on with you're methods you need to specify in more depth the connections you have made. As for now I can guess that the output is being connected to ground or some sort of load and that might be the reason you are seeing a drop out of voltage. But it might be also the case that you're output pin is changing so fast that the multimeter is not capable of reading the high state correctly</p>
