18
/ Concept to Creation: Practical Applications for Smart, Connected and Secure IoT Solutions
RN4870 & RN4871
BLE Modules
HARDWARE SETUP
Here is where things get complicated. There are a lot of external
parts in this project, so get ready. We'll be using the pins
configured in the Mouser Electronics Github in Watchdog/.
atmelstart/atmel_start_config.atstart. It is best practice
to have the board disconnected from power while wiring. It's
recommended that we mount the BMI160 and the RN4870 on a
breadboard if able.
Power
Power needs to be supplied to the BMI160, the RN4870, and
the Vibration motor; everything else can be handled by pins. If
you are using the MIKROE-2543, 3.3V and GND are marked on
the board.
Vibration Motor
The vibration alarm is the second most important external
component (behind the RN4870). The motor cannot be powered
by an output pin on the board, as they are current limited, so we
will use a transistor to give it more juice.
SAM C21 Xplained Pro
Evaluation Kit
• ATSAMC21J18A Microcontroller
• Embedded Debugger with USB interface
• Application examples in Atmel Software
Framework
LEARN MORE
• Fully qualified Bluetooth
®
smart module
• ASCII Command Interface API over UART
• Scripting engine for hostless operation
LEARN MORE
LEDs
The LEDs are to help the user understand what the band is
doing. We are using three green LEDs and one RGB
mounted to the breadboard.
BMI160
We need to communicate with the BMI160 to configure motion
events and interrupts. We will be using I
2
C to communicate with
the module.
RN4870
The RN4870 uses UART to communicate with external devices.
The pins for the RN-4870-SNSR are different than the pins of
the MIKROE-2543.
CONCLUSION
The prototype is now complete. Just plug it in, run the code,
and you're off. Watchdog solves a rather small problem. Many
people would argue that parents should just pay more attention
to their children. I can see the reasoning behind that. Most of
the time, parents are paying attention; but no mistake happens
intentionally; and when it comes to kids, anything that helps
avoid mistakes is welcome.
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