Arduino UNO R4: Nice upgrade or troublemaker?

After 12 years, the UNO R3 is finally getting an update in the form of two new UNO boards, the Arduino UNO R4 Minima and the Arduino UNO R4 WiFi (that's how Arduino spells it even if the correct spelling should be hyphenated).

As an educator working with students ranging from teenagers to 60 years old, I had to order the new boards as soon as they were available to see how the new versions will fit in my classrooms.

I've been using the R3 (and its clones) for several years with total beginners, so that's the focus of my review: How will they fit in a beginner environment ? What might happen when a total noob starts looking for tutorials? How many migraines will I get because of weird edge cases that newcomers are sometime better at finding than more advanced users ?

Resources used in this video :

- UNO R4 Minima :

- UNO R4 WiFi:

- Components datasheets:
Renesas ISL854102FRZ-T

- Other reviews:

[lgp_yt]

Somehow, this video made 20 times more views than my previous videos, and it made me double my number of subscribers!
So thank you again to everyone who watched, commented and subscribed!

This video was released only a few days after the release of the boards, so let me give some updates:
- I was able to run a debug session on the R4 WiFi using Platform IO without any external hardware

For those who asked for an in-depth review or more code examples, here some nice reviews made by other channels that I've found :

[bumpedhishead]

Please slow down! I understand English is not your first language, but your fast speech & accent are very difficult to follow. You have excellent content - just slow down!

[elreypic]

It seems Arduino is trying to get involved into 32bits world. But, I think it would be very difficult to beat ESP32 and RASPEBERRY PI Pico. They are really cheap and very well documented.

[Lord_zeel]

What confuses me, is the use of an ESP32 for WiFi on these things... when the ESP32 is a more capable microcontroller in its own right. Am I missing some big obvious thing that makes this logical? Or shouldn't they have just used the ESP32 as the main processor?

[DQSoft]

Regarding the LED matrix in the R4 WiFi, it looks fun but I wonder how many projects will use it (specially when the board is inside a box or you use a shield). I think this kind of functionality should be on a shield not in the main board.

[LibangF]

We need a basically 328P refresh drop in chip from Atmel, still 5V, more memory, more ram, higher frequency, maybe better ADC, DAC etc... Uno need this, not that microcontroller from Renesas

[getsmartpaul]

Merci ! I don't speak French ha ha . I wish I could understand your very fast English accent. Thanks goodness for the closed captions. I appreciate pointing out issues in the tutorials that can cause problems.

[IamTheHolypumpkin]

Kind of not a fan. I'm bothered by the change of architecture. For me, I do not associate the brand name with the formfactor but with the Achitecture.

For me Uno means AVR Achitecture. I was already unhappy with the Nano brand switch to ARM (Nano 33 IoT, Nano 33 BLE).

Don't get me wrong I have nothing against using ARM chips.
By now I used 6 Nano 33 IoT Boards for personal projects.

In January made my Arduino Hobby to employment and now work as an Embedded Systems Developer. There I developed with the RP2040 (Raspberry Pi Pico) which too is an ARM chip. But depending on the project an 8bit Achitecture can be superior to a (comparatively) complex 32bit Architecture.

But now generally a great product while not attractive to me, I have more than enough spare controllers to last me a couple years and when I used those up I'll switch to custom PCBs.

[oienu]

For advanced users, a lot of confussion, for beginners, they still will use "digitalRead(1)" so. . . the troubles will start at deprecated libraries using AVR instructions :, D I had to get a Leonardo even when I had a Zero because they didn't work on the Cortex architecture.
About analogWrite I ever had that problem, they should name it pwmWrite to avoid confusions. I like how in mbed they have AnalogOut and PwmOut to be clear what do each.

[lovemadeinjapan]

What I missed in the video is compilation time. In my classroom, compilation time is key. For a Leo, MEGA or UNO it is near instant, compilation for a Microbit is also very fast, Teensy ditto, but for M0/M4 boards is was much slower, and for ESP32 it is unbearable slow (1 minute compilation time!) I do not agree about the confusion with Serial and Serial 1, we use Leonardos for ages, because they have dual UART, which is a must have for GPS, GSM, MIDI and stuff like that. I also hope they kept SPI exclusive to the ISCP header, and no wiring through pins 10-13 as well. Another reason I prefer the Leo over the original UNO: you have extra pins and easier SPI hookup. I also quite often use the 6 extra analog inputs on the LEO, especially for multi-analog-stick gaming projects many students make. I actually dilike USB-C, as the port dies easily in classrooms, and USB-B can be soldered by hand easily, USB-micro is doable as well (1mm spacing), yet USB-C connectors need a reflow machine for repair.

[mkpeker]

While it's still on market, I'll buy myself another Original Uno r3

[racingtogreen]

Haven't started playing with mine yet. Anyone tried this one with Arduino IOT cloud ? Wondering if there is any more success with this board and the cloud agent, which seems to be seriously flawed. I'm not sure if Arduino just isn't into the cloud implementation long term, or if the development is just a little out of their level of ability. This really could be IOT for the masses if they can get on top of the cloud agent issues.

[AttilaAsztalos]

No "revision" should change the hardware capabilities of a thing. "Uno" means "atmega328 based". If they wanted a new chip fine, but they should then have called it "the Trentamila ventisette" or whatever.

[fparisi]

almost all projects in the arduino world require more than enough computing power with the R3. I don't understand the usefulness of this upgrade for the Arduino world, after all if I want to use ESP, I use an ESP... and it costs even less.

[hobbyrob]

it's all nice but let's not make it difficult now please!
for example I can't work very well with that ESP32 OR!!!
a video REALLY needs to show everything step by step and really not skip anything, maybe then it will work with something like ESP32.

I am very happy with the simple old Arduinos!
( And honestly, clones too )

Regards Rob

[jazzboy]

The lack of a crystal has rendered the R4 not useable for my turntable projects that are driven by SimpleFOC. Have several old Unos that work superbly, but i tried an R4 and no joy as the speed of my turntable was nowhere near as accurate as with an old Uno.

[surenbono]

...add piezo & hc-12 (rf) embedded with newer board...

[allanseidel]

I find Arduino released this thing without making sure the reference material thoroughly covers the programming differences between this Renesas RA platform and the platform the UNO R3 uses. Does a library environment for this new platform exist?
For example, try figuring out the interrupts and the available interrupt types. See if the reference document code for interrupts actually compiles or functions as advertised. See if you can get pin change interrupts working. Please show us how if you manage this. I agree this R4 will be frustrating until the public Arduino community catches up with functioning libraries and documentation having functioning code examples.

[carlosevaristocardona]

THANK YOU FOR THIS USEFUL INF. ONLY ONE SUGESTION. SPEAK MORE CLEAR AND SLOW DOWN NO BODDY IS CHASING YOU.THANKS.

[iarnvida]

thanks for the review ! I was really interested in the LED matrix ( for tamagotchi reasons :3 )
Can't wait for your feedback about the future wifi features ;)
btw, excellent video format, love it !!