#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:

Notes

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:

Construction

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

• Maker Uno - Cytron listing
• Cytron
• ..as mentioned on my blog