When looking for a new Wi-Fi ready Arduino recently, I was given the choice of an UNO or an MKR. This wasn’t an easy decision so I’m sharing in this guide a summary of the research that I put into figuring out if I should buy an UNO or an MKR.
The main difference between UNO and MKR is that MKR boards are designed for cloud connectivity and Internet of Things projects, while UNO boards are designed for general-purpose prototyping with the widest range of compatibility. MKR boards typically cost between $32 and $38 and mostly include WiFi and Bluetooth. UNO boards cost between $23 and $45 and only include WiFi and Bluetooth on the more expensive boards.
In general, MKR boards are better for use in projects that communicate with the cloud, such as collecting data from sensors and uploading it to cloud services.
While UNO boards are better for projects that involve utilising Arduino shields, such as display panels and motors. This is due to the UNO having a greater shield compatibility than the MKR family. I’ve included examples of good projects for UNO and MKR boards below.
MKR boards are not compatible with many shields due to their lower operating voltage. Most shields are designed for an operating voltage of 5V, which UNO boards operate at. MKR boards operate at 3.3V which means that many shields will not work when connected to an MKR board. I’ve included more details on technical specs below.
I’ve included a full guide below comparing UNO and MKR on the following items:
- Cost comparison between UNO and MKR
- Projects where the MKR is better and projects where the UNO is better
- Technical and feature differences
MKR vs UNO: Cost Comparison
The Arduino MKR family typically costs between $25 and $38; the UNO family typically costs between $23 and $45. The more expensive boards offer more connectivity features, particularly WiFi and Bluetooth, while the cheaper boards can offer a smaller size in addition to the lower price.
Typical costs of Arduino boards in the Uno and MKR families are listed in the table below:
|MKR WiFi 1010||$32.10|
|MKR WiFi 1000||$38.00|
|UNO WiFi Rev2||$44.80|
The more expensive boards in both families (MKR WiFi vs UNO WiFi Rev2) include more connectivity options, particularly WiFi and Bluetooth. The cheaper boards (MKR Zero vs UNO Rev3) do not have as much connectivity.
For using WiFi or Bluetooth, consider the MKR WiFi 1010 or UNO WiFi Rev2.
For general use if saving money, consider the UNO Rev3.
A WiFi shield can be added to an UNO Rev3 later for roughly $10-$20 depending on the manufacturer. It appears as if Arduino no longer offer an official WiFi shield, or at least I couldn’t find one available for sale. They do have a guide on their website about how to use the official WiFi shield if you do manage to find one though; the guide is here.
A Bluetooth shield can similarly be added to the UNO Rev3 and costs roughly $20. Similarly, Arduino used to sell an official Bluetooth shield however it appears they no longer do.
Adding shields to MKR boards can be more difficult due to their lower voltage level. Check to make sure any shields you want to use with an MKR board are compatible first.
Further details on projects and technical differences (e.g. pins and voltage) is included below.
Projects MKR is Better Suited For
The Arduino MKR family is designed for quick prototyping of IoT or audio processing projects. MKR is short for “maker” with Arduino targeting this board to makers and engineers.
Projects that the MKR is good for are typically those that involve cloud connectivity, such as recording environmental data and uplaoding it to the cloud, or interpreting data already stored in the cloud. The MKR family also targets audio processing projects, though this is predominantly with the Zero and Vidor boards (these do not come with as many connectivity options however).
Some interesting projects I found for MKR boards on the Arduino website:
- Gathering environmental data and storing it in the cloud using an MKR WiFi 1010
- A GPS tracker using an MKR Fox 1200
- Cloud controlled pellet smoker using an MKR 1000
Projects UNO is Better Suited For
The Arduino UNO family seems to have a lot of people making home automation projects. I like the UNO for its ability to quickly prototype in a wide variety of applications.
A lot of shields are compatible with the UNO, certainly more-so than the MKR family, so projects that need a lot of interaction between shields and external projects can benefit from using an UNO instead of an MKR.
According to the sales page, UNO is the most used and documented board in the Arduino family.
Some interesting UNO projects I found on the Arduino website:
- Interactive touch screen panel using the UNO Rev 3
- High precision scale, also using the UNO Rev 3
- A 3D printed robot (also UNO Rev 3)
MKR vs UNO: Technical and Feature Comparison
The table below compares the technical features and specifications for the leading boards in each family:
|Uno Rev3||Uno Rev2 WiFi||MKR 1010|
|Clock speed||16 Mhz||16 MHz||32-48 MHz|
|Digital I/O Pins||14||14||8|
|Analogue Pins (Input/ Output)||6/0||6/0||7/1|
The MKR 1010 board has a higher clock speed than the latest UNO series boards. I guess this is what makes it better for audio processing projects (not something I’ve personally done myself). The MKR boards also have more analogue pins.
It seemed like the MKR family was originally designed for the connectivity required for IoT projects (i.e. Bluetooth and/or WiFi) and this was their edge over the traditional UNO boards. However, the UNO family has a WiFi and Bluetooth board available (the Rev 2) which negates this advantage. The MKR family is typically smaller though and has the below-mentioned battery compatibility.
MKR boards also typically have built-in support for charging lithium-ion batteries, including automatic charging and automatic switch-over between the USB and battery power. Recommended battery size is between 700mAh and 1400mAh – the lower end due to the MKR’s fixed charging current and the upper end due to a 4 hour timer on the charging circuit to prevent over charging. Larger batteries can be used but it seems the automatic charging needs to be re-triggered after 4 hours.
UNO boards are compatible with more shields than boards in the MKR family. Most shields are designed for a 5V operating voltage, which is generally incompatible with the MKR family’s 3.3V operating voltage. I haven’t tried using a 5V shield with an MKR board, but I don’t imagine it would work too well (on some shields it may be possible however).
Overall I found:
- MKR is generally best for gathering data from sensors to send to the cloud
- UNO is the go to if you need wider shield compatibility
- For beginners, consider sticking with one from the UNO family (the Rev 3 or the WiFi Rev 2)
For me personally, I went with the UNO WiFi Rev 2. It was general purpose (suitable for someone like me who didn’t have any particular project in mind) and offered great compatibility with shields.
If you want to check out some of the references I used in putting this guide together, check out the links below: