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Project Notes

#423 MakerUno

Checking out the Maker UNO, a feature-packed Arduino-compatible board from Cytron in Penang, Malaysia.


Here’s a quick video of the board in action:



I was recently shown an Arduino-compatible board made by Cytron in Penang, Malaysia called the Maker UNO. I gather it began life as a very successful kickstarter that aimed to produce a better board and associated teaching materials for K-12 education.

It packs quite a few additional features in the Uno form-factor:

  • LEDs on all digital pins
  • a piezo buzzer on pin 8
  • a push-button on pin 2

It uses the CH340G USB-UART chip for USB connectivity, so additional drivers may be required. See LEAP#405 ATmegaSerialProgrammer for a deeper dive on the CH340G.

And a really nice feature is the price - currently listing for RM15 (~$3.60 USD).

It also looks pretty spiffy to boot:




The full schematic is available from Cytron:


Here’s a re-drawing that focuses on the details of the digital pin features. In particular, note:

  • LEDs are indirectly driven with low-side n-channel MOSFETs
    • presents a high impedance to the pin, so its normal function is largely unaffected
    • a high-value (3.3MΩ) pull-down resistor ensures the gate doesn’t float
  • The piezo buzzer on pin 8:
    • connected in addition to the LED
    • switched with an NPN and 1kΩ base resistor
    • has a manual SPDT switch that can be used to disable the buzzer
  • Push-button on pin 2:
    • with resistor that pulls the pin low when the button is pressed
    • should be used with INPUT_PULLUP pin mode
    • pin 2 supports hardware interrupts, so allows interrupt-driven coding rather than polling of the button state
    • connected in addition to the LED (the LED will normally be on, and go off when the button is pressed)


Code Demonstration

The MakerUno.ino sketch is a simple demonstration of the features, requiring no additional components:

  • steps through the digital pins (except 2 and 8), lighting the LED
  • plays a tone proportional to the pin number
  • on a falling interrupt from a button press, reverses the order that it is cycling through the pins/tones

Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.