5 Myths Everyone Believes about Arduino (that aren’t true)

Having spent the past 6 years writing code for the Arduino platform, I’ve noticed a trend in myths from both new-comers and veteran users. Here are the Top 5 Myths I see come up on forums, in classes, and on IRC.

1. The Arduino uses its own Language

This myth isn’t helped by the Arduino.cc home page which says

“The microcontroller on the board is programmed using the Arduino programming language.

While it is true that the structure of an Arduino sketch looks unique, it is really just C++ with a tiny bit of preprocessing. Users writing “Arduino Code” are actually writing C++ with, what I call, the Arduino Library. Functions like digitalWrite() are just that, C++ functions.

So while the Arduino Library does a great job of making microcontroller programming very simple, it is not its own language.

2. Pin 13 Has a Resistor

Countless tutorials have lulled newbies into this trap. The very first Arduino board, of which something like 200 were produced, had a LED and series resistor on Pin 13. That’s the only board which did. So you should never never never connect a LED to Pin 13, without a resistor!

Update: Clarification. There *is* a resistor on Pin 13. However, it is only connected to the LED that is in series with it to ground. So that resistor does *nothing* to protect anything you attach to the pin, like your own LED.

3. Commercial products don’t use Arduino

Corollary: “real” engineers don’t use Arduino!

Okay. I try not to toot this horn, but I’m a “real engineer.”  You already know that: it’s in my twitter name and URL. Here’s a top secret piece of information:  I use Arduino. Now it is true. You aren’t going to go to Best Buy or your local big-box electronics store and find any products that have an “Arduino Inside” sticker. However, Arduino is a prototyping platform. You aren’t going to ship an Uno with every product. You might, however, develop a product with an Arduino and embed the ATmega328 inside of it. Or, more likely, you’ll prototype the idea, run it through a crowd funding effort and then redesign.

You have to define what “commercial” means, but there are plenty of products out there that started with an Arduino in the early stages.

Ever hear of 3D printers?

4. analogWrite() is Analog

This one catches a lot of people who don’t really understand Pulse-Width Modulation. With the exception of the “Due”, Arduino boards do not output “analog” signals. (Note, you might want to watch this video on the difference between Analog and Digital.)

PWM signals are actually digital signals, where you change the length of time between the “on” and “off” states.

5. The Header Spacing was a mistake (or it wasn’t.)

If you know anything about the Arduino pinout, you should know that the spacing between pins 7 and 8 isn’t 0.1″ (or 2.54mm). At one point the Arduino web site had this in the FAQ as an “eleventh hour” mistake. Then there was the explanation that it prevented shields being plugged in backwards. Now, I’m not sure if it was intentional, but it is true that a benefit of the spacing is that you can’t plug in a shield backwards.

The perceived downside to this decision is that it makes the board difficult to plug into a breadboard, or a shield into a breadboard. However, magic jumper wires do exist which solve this “problem.”

Okay, so those are the 5 Myths I encounter most.

Question: What other myths have you heard or helped to dispel? You can leave a comment by clicking here.

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62 thoughts on “5 Myths Everyone Believes about Arduino (that aren’t true)

  1. There are many mis-understood things about the Arduino.

    The 5 items listed are some questions I have gotten about Arduinos as well.

    These (and many others) are the type of questions beginners ask, but not those whom have not started the learning process.

    Look at the “myths” proposed:

    1. The Arduino uses its own Language
    2. Pin 13 Has a Resistor
    3. Commercial products don’t use Arduino
    4. analogWrite() is Analog
    5. The Header Spacing was a mistake (or it wasn’t.)

    Items 2,4,5 are asked by those who have started learning about those things, that only someone who has looked at the manual or demo programs.

    Item 1 is Arduinos fault as baldengineer has discussed.

    But item 3 is a ringger !!

    A beginner may ask this question because they think their great idea will make them a million bucks. 😉

    But as I have stated previously, I let those would be entrepreneurs know how hard it is to bring a real product to market.

    Now if item 3 said: “real” engineers don’t use Arduino! , I would agree, that this statement is a myth.

    • Hey it’s not hard to bring a product to market entrepeneurs just like to think it is so they can bang on how great they are. Not hard but lots you need to do other than write code and build Pcb’s.

  2. When millis() rolls over, it is TEOTWAWKI. Magic smoke will be released, the board will reset, the sketch will hang, dogs and cats will sleep together, etc. The fact is, the only limitation with millis() is that it cannot be used to time events that last more than about 49 days.

  3. I think there are some misunderstanding about the role of shields available for Arduino. For example, I hear many friends doubt that Arduino can NOT communicate with a WiFi transceiver without a WiFi-Shield !

    Even though I didn’t try that, I believe that Shields are important but not necessary ! So hope someone explain in what really shields do for Arduino ..

  4. Regarding myth 3.

    I have been involved and designed the programs for a light module for model railway houses. We used a clone of UNO called Brage (Swedish educational version). Small form factor.
    Every house has a Brage inside connected in a group to a Uno with ethernet to a central PC-program controlling over 100 Brage modules for synchronizing the light effects. A simple but yet vesatile system based on Arduino products.

    It’s not a commercial product itself but Its used in the same way. It will be used in a “professional” manner.

    So I think defenitly it can be used in real world applications.

    Yes, I am an enegineer and have worked with programming since late 70’s. Worked as a manager for many years, but I fell in love with Ardunio and was excited over the possibillites to create this application. The whole system was up and running within a week of programming in my spare time.

  5. Myth #6: There is a reason for non-typical, non-rectangular shape (form factor) of the Arduino board.

    Reality: No, there is no special reason, they just wanted to be “different”.

  6. Hello,

    Commenting on Myth 3,

    I consider myself more or less an engineer. I am a PhD student with an electrical engineering background currently in the field of biomedical engineering focusing on surgical robotics. Many times I love to go into the Arduino platform just for proof of concept and prototyping. I have done so for years and have been proud of it. It is feasible and community support is through the roof.

    Although Arduino is open-source and many say it is targeted for beginners, research and industrial engineers do use it thoroughly. My personal board is the Due because of the ARM processor – matter of fact the Arduino Due truly did push me into ARM designs into my custom PCBs. I do believe the Arduino is a viable tool for any engineer. And although your final design may not have the legendary Arduino logo, you can bet your ass that in many final products, there is a good chance it may have used the Arduino as a prototype.