Inclinometer with 17 Segment BarGraph Display

This project is an inclinometer based on the ADXL203/ADXL103 accelerometer chip and the Arduino microcontroller ATMEGA328. The device measures tilt and displays it on a 17-segment bar graph display. The ADXL203 provides an analog value, which is read by the ATMEGA328’s ADC A0 and displayed on the LED bar graph. The project also includes an optional on-board buzzer and driver circuit, which can be used to create an alarm at a certain degree of tilt. This feature is not populated on the board by default but can be added if required. On-board solder jumpers J1 and J2 are provided to select the X-Axis or Y-Axis of the ADXL chip since the chip has 2 axes. Users may additionally use single-axis chip ADXL103 instead of ADXL203 dual axis.

The buzzer circuit can be connected to either the D3 or D11 pin of the microcontroller, using a 2.2K 5% SMD resistor (R22 for D3 or R13 for D11). The recommended buzzer is a 12mm – 5V type, and the transistor Q1 is a BC847 SOT23-3.

Arduino Programming

The board features a 4 x 2 pin connector for bootloader and Arduino programming. Users can refer to the provided link for more information on Arduino programming and bootloader installation for the ATMEGA328 chip.

https://docs.arduino.cc/built-in-examples/arduino-isp/ArduinoToBreadboard/

Arduino code is available for testing the board, although it is noted that the code may not be entirely accurate. Users are encouraged to experiment and modify the code to suit their specific application requirements.

When the board is kept at a zero-level position, the D9 blue LED is turned on. As the PCB is tilted, 8 LEDs follow the tilt in one direction, and 8 LEDs follow the tilt in the other direction.

Overall, this project appears to be a simple and effective inclinometer solution, suitable for applications such as vehicle leveling (e.g., RVs, motorhomes, and platforms). The optional buzzer feature adds another layer of functionality, allowing users to set alarms at specific tilt angles.

Features

• Power supply: 5V DC @ 100mA
• On-board Tilt Sensor ADXL203
• 17 x LED bar graph display
• 4 x 2 Pin Connector for Arduino Programming
• Easy mounting with 2x3mm mounting holes
• 3 x Blue LEDs, 6 x Red LEDs, and 8 x Green LEDs
• PCB Dimensions 94.93 x 22.38 mm

Connections

• CN1: No Use
• CN2 Programming Connector: Pin 1 = VCC, Pin 2 = D11, Pin 3 = D12, Pin 4 = D13
• CN3 Programming Connector: Pin 1 TX, Pin 2 = RX, Pin 3 = Reset, Pin 4 = GND
• CN4: Optional – No Use
• CN5: Optional- No Use
• Power Input: Pin 1 of CN2 = VCC, Pin 4 of CN1 = GND can be used to power the board or use CN4 or CN5 to power the board

Arduino Pins

D3=LED01, D3=LED02, D5=LED03, D6=LED04, D7=LED05, D8=LED06, D9=LED07, D10=LED08, D11=LED09, D12=LED10, D13=LED11, A1=LED12, A2=LED13, A3=LED14, A4=LED15, A5-LED16, D2=LED17

Schematic

Parts List

Gerber View

Photos

ADXL203 Datasheet

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