KEYESTUDIOLeonardo R3 Microcontroller Development Board with USB Cable Kit for Arduino Project

Overview: I am pleased w/ this purchase. I use it as an "Uno substitute": its useful for prototyping, but I'm unlikely to use as the final MCU in a project. It is 50x70mm, matching the board size of a Genuino Uno.Details and testing:Packaging: Arrived in a Keyestudio display (cardboard) box, inside a 2nd crush-resistant cardboard box. The package includes a serial cable.Appearance: The board has "spiffy" yellow labelling and yellow headers on a black background.Components & electrical testing: The microprocessor, in the 44-pin TQFP form factor, is labelled "Atmel mega32U4, -MU, 2335 PU". On-board voltage regulator is the AMS1117-5v. With a 9-v battery plugged to the barrel jack (or the Vin pin), Vout is 5.04v.Functional testing:(a) Program upload: With a 9-v battery attached, the on-board LED flashed at 1 Hz, implying the "blink sketch" is running and the Bootloader is present. No need to install other software (e.g., QMK firmware). I opened the Arduino IDE, plugged in the serial cable, then checked Tools|Port. The IDE recognized the board as "COM# (Arduino Leonardo)".(b) UART-USB-Serial interface: Unlike some 32U4 boards, this MCU has on-board UART IC, making serial programming easy. I selected Tools|Board|Arduino AVR boards and chose "Leonardo". I created & uploaded a "Hello World" sketch and opened a serial window => success.(c) Analog pins/ADC: The ADC and all analog pins were functional. I created ~2v at the mid-pt of a voltage divider and measured the value returned from the A0 pin. The value was in the expected range (422, corresponding to 2.2v, w/ similar values fr pins A1-A5, as well as, a Genuino Uno).d) PWM pins: I successfully made LEDs attached to PWM pins (3, 5, 6, 9, 10, & 11) fade.e) Memory: successful access to flash [32kb (28.7kb+bootloader)], SRAM (2.5kb) and EEPROM (1kb), confirming the expected values.

You probably won’t be able to figure it out by looking at it but this is a serious little computer. It contains a Nordic Semi nRF51822 ARM Cortex-M0 microcontroller which, for those who don’t know, is quite powerful in addition to containing a BTLE radio. I never thought I’d see this chip on an educational board for 6th graders because it’s usually rather serious stuff that’s more difficult than average to program.Don’t be fooled by the 6th grade graphical programming interface. This thing could be used by embedded systems engineers to prototype a variety of Bluetooth products using any Bluetooth profile that exists, yet Microsoft MakeCode has made it easy enough for kids with no special knowledge to program. (Of course MakeCode can’t be used to do everything you could do with C and ARM CMSIS, but I’m still impressed with what you can do which includes some limited radio communication and extensions built by third parties like AdaFruit.)The only thing I don’t like about it is the edge connector, which is great for working with alligator clips and 3 GPIO pins, but if you need access to the other pins you’re really going to need a female edge connector which will cost you about $10 for the breadboard adapter version. Other small microcontroller boards either have bottom male header pins that will plug directly into a breadboard or they have top female headers that can easily be used with jumper wires.So for the most part this is just great, but I think they really should have tried harder to come up with a breadboardable design that doesn’t require an edge connector. I can think of some ways to get both pin headers and alligator clip pads on the same board. Breadboard connections are essential for going beyond the basics which older kids and adults are sure to want to do if this is their first board.So buy this if you:- Want an easy to code board that uses MakeCode- Want a board with some nice features like the LED matrix and the accelerometer- Want a nRF51822 with Bluetooth capabilityDon’t buy this if you want something you can breadboard and get more advanced with right away. Instead I’d recommend buying an arduino breadboard kit with jumper wires and accessories.The KEYSTUDIO kit is a good one, everything was brand new and as expected. The battery pack is essential if you want to use this primarily with an iPad.

Works perfect, been learning stuff on Uno and wanted try making a sim racing button box so needed something with HID capability. Using this with Simhub made that very easy. This board is perfect for developing HID devices.

Used it for a project for school. It worked perfectly as intended.

keyestudio Leonardo R3 Development Board came nicely packed without any damage.Et has got 23 digital Input/Output ports and 7 PWM ports and 12 analog input ports.This development board is great prototyping tools for the electronic projects and this can be used by connection it to a computer with a USB cable or power it with and AC to DC adapter, And this development board comes with USB Cable

Got this so I could wire an analog joystick to a PC with the Leonardo being seen as an HID. Worked awesome when I flashed it with a program containing the joystick.h library. Came right up as a game controller on Windows.

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Locks up when trying to program. Selected Arduino Leonardo, press upload, leds flash for a bit, then the board does a full reboot releases the com port and comes back, Arduino IDE times out with an error "unknown programmer response"