Reason for question: My son is working on a project to build a robot controlled by an arduino uno. This question is more about terminology than process, but since terms are very important at this level, I rather ask some expert advice - I have not found any input on the internet about this!

Question: What is the correct technical name (if any) of the circuit board that acts as the interface between the arduino-uno (a micro-controller) and the motors (the external devices)? According to the definition of a motherboard*, this "interface" circuit board would act as a very basic motherboard, as it would "allow communication" between the components, but it would not contain expansion slots, so should it be called something else?

Background on project: The robot will be very basic. A body will be made of plastic legs and motors for joints; an Arduino-uno will provide the logic for motor movement; and a custom circuit board (hence my question) will act as the interface between the uno and the motors, providing electricity from a dedicated source to the motors.

We are just missing the proper terminology to use for this "interface" board and I cannot find any concrete info online or on books. If I get good terms in this post, then we can do further research on those terms. Thanks.


  • 4
    "interface board" is perfectly fine terminology Commented Dec 1, 2016 at 0:05
  • On Arduino contexts, these are often called shields. I kinda dislike this, because every dev board tries to have its name (HATs, Capes, Shields, etc etc..).
    – Wesley Lee
    Commented Dec 1, 2016 at 0:20
  • 1
    Thanks for the quick responses. I spent at least 6 hours over 4 days reading articles and books for this info with no luck. After researching both terms (interface board and shield), they both seem to work good for our purpose. We will probably go with "Interface Board" just because it is easier to grasp (think marketing), although "Custom Shield" is probably more "correct" when specifically talking about Arduino. Thanks again!
    – TFK
    Commented Dec 1, 2016 at 0:40
  • 1
    No, "custom shield" is nowhere near correct. In the terms of professional EE, "custom shield" means something like this. Don't fall for the cute marketing-to-amateurs slang.
    – Nick Alexeev
    Commented Dec 1, 2016 at 2:18

3 Answers 3


I would call it an "interface" or "driver" board. You don't need to get too hung up on the exact name.

The word "shield" is one of the Arduino-peculiar words (like "sketch" for "code") which now has a generally-understood meaning. That meaning is, something that plugs directly onto the Arduino board, with the pins on the shield matching the sockets on the Arduino board.

Whilst a shield is a quick and easy way of getting started (because you don't need to wire anything) they can have their disadvantages. One being, what if you want two different functions, like a motor driver and an Ethernet interface? Two shields, one on top of the other? What if they both use a certain pin for different purposes?

I made up a radio-controlled car, see photo:

Radio-controlled car

The only shield I used was a generic "put whatever you want onto it" shield, which let me mount some MOSFETs, a radio receiver board, and other components, as required by the design. There is a Uno underneath it, not particularly easy to see. Adjacent on the right is a motor driver board. A LiPo battery is slung underneath.

This kept things reasonably compact, without requiring a specific purpose-made shield which only does one thing.

and a custom circuit board (hence my question) will act as the interface between the uno and the motors, providing electricity from a dedicated source to the motors.

It sounds like your project is similar to my car. Just assemble things in a way that makes sense to you.

  • Thanks. This answers my questions as noted by alex.forencich and wesleylee. Note although I agree with you that we should not get too caught up in the terminology (specially as hobbyist), this is for a judged science fair project where the research paper carries more weight than the built product, so having the correct terminology is crucial. I'll tell my son to call it an interface board and to find a peer reviewed reference from the library (these kids now a days even have to add doctoral references in all research - it's good, but insane at the same time). Thanks again.
    – TFK
    Commented Dec 1, 2016 at 17:36

In the Arduino ecosystem these boards are called 'shields'.

Arduino describes a shield as:

Shields are boards that can be plugged on top of the Arduino PCB extending its capabilities.

For example, there is an Arduino Motor Shield which sounds very similar in purpose to the board that your son is making.


"Interface board" works as a general term, as @alex had mentioned already.

The word "motherboard" would work if it's larger than each of the components that plug into it.

The word "daughter board" would work if it's smaller than what it plugs into.

Please don't use the word "shield" when referring to extension boards, interface boards, daughter boards, and such. The word "shield" in this connection was popularized by Arduino marketing. (More detailed discussion about "shield" in connection with Arduino.)

  • I didn't know this terminology had discussion about it. Makes sense that EEs dislike the term, it doesn't really mean anything.
    – Wesley Lee
    Commented Dec 1, 2016 at 0:57
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    Depending on what is being done, the claim here may be a highly erroneous rant. If the board being designed plugs into the Arduino in the fashion of what are known as "shields" then that is the term that should be used since that is the term everyone recognized for such a board, regardless if they like the term or not. If it has some other physical arrangement, use a descriptive term. Ultimately, making such a board is probably a waste of money anyway - either hand wire it in the Arduino form factor, or replace the Arduino with a more compact and hence cheaper custom circuit. Commented Dec 1, 2016 at 3:25
  • 2
    @ChrisStratton Agreed. If you're specifically talking about a board that's made to plug into the Arduino pinout, calling it an "Arduino shield" is an excellent descriptive term.
    – user7800
    Commented Dec 1, 2016 at 4:49

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