This is our attempt to make a low power Arduino variation board. Some feature of the board:
- It uses the "breadboard" (ATmega328 on a breadboard (8 MHz internal clock)) as the board option in Arduino IDE 0018.
- Utilizes full SMD components to reduce the cost of assembly.
- Ultra can be powered by either the USB, external DC source, Li-Ion/Polymer or all of them at the same time.
- Runs on 3.3 V rail as most low power interface runs on 3.3 V rail or lower.
- A low power 32.768 kHz is present to allow the board use it as a asynchronous timing source during power safe mode. This removes the need of an external dedicated RTC IC.
- Microcontroller - ATmega328P-AU
- Clock - Internal RC 8 MHz oscillator
- External DC source range - 7.5 - 36 V, 2 A
- Battery - Lithium Ion or Lithium Polymer with temperature monitor for charging
- Battery charging - Maximum 500 mA charge current
- Buck-boost converter stage for usage of input voltage lower than 3.3 V
- On board temperature sensor - MCP9700 connected to ADC7
- Battery voltage monitoring - Connected to ADC6
- USB port protection - 500 mA resettable fuse
- Analog reference voltage with LC filter
- Indicator LED connected to digital pin 13
- Has Arduino standard breakout pins at the bottom side using SMD 2.54 mm headers
- Dimension - 55.88 mm x 68.58 mm
We tested the 1st PCB attempt in terms of functionality and found out that we forgot to supply the MCP9700 sensors with supply, :o. Have yet to measure the current consumption especially during power save mode but we hope it goes near the design specifications.