Arduino Industrial 101 I/O's problem.

Hi, i'm experimenting some issues with my Arduino Industrial 101. I couldn't find good info about the board, but it seems to have 20 I/O pins (7 on header). What are the "on header pins" used for? I have tried to use the D0-D7 pins to turn on and turn off a 8 channels 5V relay, but i don't understand how they work. When i write them as HIGH, the relays connected to pins D1 and D2 turn on at the same time, and the only pin that "works" correctly is the D1, i don't know why. The D2 pin turns on too. But, the others don't turn on even when i use the digitalWrite function and put them to HIGH. I expect someone knows how this board works and if there is a solution to make the I/O's work fine.

Thank you. Greetings!

Hi, What is an Arduino Industrial 101? Where did you get it? Link to info??

OK, I see this on Adafruit:

The Arduino 101 is very new, and uses a completely new core chipset! Many libraries won't work with it, it's currently recommended for makers & engineers who want to try out the latest and greatest!

@Guille2812, please do not cross-post. Other thread removed.

@Guille2812, please stop cross-posting. Other thread removed.

terryking228: Hi, What is an Arduino Industrial 101? Where did you get it? Link to info??

OK, I see this on Adafruit:

Thank you! Here is the info about the board:

I just want to use the I/O pins as outputs, but the D pins (i supposed the D is "digital") don't seem to work properly. At least, i don't know what to do or where the real digitial I/O's are. I need 8 outputs for my project, but i think i might fix it with only 6. The board is so new that i can barely find info or examples using it.

Thank you again. Greetings!

Hi, Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.,148850.0.html then look down to item #7 about how to post your code. It will be formatted in a scrolling window that makes it easier to read.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

We need to see how you are using the relays ans what their specification is.

You cannot drive the relays directly from the pins, the spec of the 101 tells you they are limited to 40mA.

Thanks.. Tom.. :)

Hi, I'm using a 8 cannel 5V relay from Elecfreaks. Here is the info about it:


The realys are limited to 20mA, so i think that is not the issue. The schema The code is ok, it is just using the digitalWrite() function when the board receive a command by Serial connection, but i tried with an Arduino Micro and it works fine. The problem that i have is how to use the Industrial 101 board. I don't know how can i use the digital I/O pins. About the relays... I'm just connecting the 5V from the Arduino to the VCC in the relays, the same with the GND to the GND, and, finally, each digital pin configured as an output to the different channels in the relay. Am i doing something wrong?

Thank you for the answer! Greeting.

That Arduino uses 3.3volt logic.

The relay module is designed for 5volt TTL logic.

Not going to work. Leo..

Hi, That relay is probably the problem.

There are some relay boards that have optical isolation and need very little current to operate that will work with 3.3V signals from Arduino. They still need a separate 5V supply to run the relay board. See the schematic diagram and info HERE.

DISCLAIMER: Mentioned stuff from my own shop...

Hi, Thank you both of you for the info. It is weird because with an Arduino Micro it works great and i thinked the Industrial 101 would also have a 5V logic, but i'm not pretty sure. I'll try to make the diagram that @terryking228 posted. Thank you again!


On the industrino do you have to put links in to connect the I/O ports of the processor to the outside world connector on the prototyping area ? The links , I think , are left open in case you want to add parts in the prototyping area before output reaches the outside world

The board is normal 5v logic so the digital said should drive the relays .

The board is normal
5v logic so the digital said should drive the relays .
Processor: Atheros AR9331
Operating Voltage: 3.3V

Picture of one driver on that relay board.
VCC must be 5volt for a 5volt relay, so base drive can’t be 0/3.3volt.