Maximum Arduino connect to computer

Hallo all,

I am Hisar, now my office using arduino mega for store system. We develop the software with our team and using arduino mega to open and close locker at the store. We already done with our first store using 8 arduino mega. Now we expansion to store 2, the total arduino we need is 17 units. Is there any limit arduino to connect to the computer? because when i connect 15 arduino there is no problem, but when i connect number 16 and the operator do the system the computer got BSOD? Please help me to get the solution, is there problem of the computer power supply or anything else?

NB: the computer using 3 USB 2.0 PCI 5 port and 2 USB 3.0 PCIe 4 port.

Thank you in advance Hisar

Why not connect one Arduino Mega to the PC and connect the other Arduinos to it?

What does each Arduino do? Maybe one Arduino could do more than one thing so that you would not need so many.

By the way I have no idea if you might run into USB power problems. Maybe use a powered USB hub?


Hi Robin,

Thank you for your reply. The arduino open and close store locker base on command that our apps give to it. To open and close that locker we using step motor and controled by relay. Simple schema is apps=>arduino=>Relay=>run the motor=>relay=>arduino=>apps. 1 arduino handle 11 locker.

i am so sorry i do not understand so much about this because i am the IT guy and who to make the system with the arduino is our programmer team. What do you mean connect 1 arduino to the PC and another arduino to it? is that possible?

Hisar: What do you mean connect 1 arduino to the PC and another arduino to it? is that possible?

There are various ways for one Arduino to communicate with another.

For example a Mega has 3 spare HardwareSerial ports that could each connect with another Arduino for 2-way communication. Or one of the ports could communicate with several Arduinos if you have system to ensure only one of the others "talks" at any one time. This would also need a little hardware tinkering to prevent the non-talking Arduinos from confusing things because the Serial system keeps the line HIGH when idle.

You can use SPI or I2C to provide two-way communication with one master and several slaves.

You can use wireless (such as the nRF24L01+ modules) to allow one master to communicate with several slaves.


:sob: if we do that so it's mean we need to rework all the wiring. But anyway thank you Robin for your advice, i will say to the team to consider this idea if we still stuck on the BSOD problem.


How are you powering the Arduini? If all the electricity is coming from the computer, for all 17 boards, you could be drawing some serious amperage ...