Liquid-Level Monitoring Using a Pressure Sensor – Bar-Graph Display

Rajkumar Sharma
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Tested
SKU: EL140979
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This project allows users to monitor the liquid level on a Bar-Graph display. The liquid level is measured using a pressure sensor, the sensor is placed on top of the tank and is connected to an open-ended tube that is submerged in the water tank. The amount of water in the tank creates a proportional amount of pressure on the sensor via the trapped air in the tube. The pressure sensor produces an equivalent output voltage. This voltage is monitored by the ADC of ATMEGA328 microcontroller and displayed on a bar-graph of 16 LEDs connected to the I/O pins of the microcontroller. The project is based on an Arduino-compatible microcontroller. Example code is written using Arduino IDE and is provided below. This project can measure water levels up to 100 cm (1m). Users may use other LED colors. Trimmer potentiometer PR1 is optional for other applications, turn full CW.

MPXV5010DP pressure sensor from NXP is used to measure the liquid level. This is an analog pressure sensor and the output of this sensor is 0.2V to 4.7V which is proportional to the applied pressure range of 0-10kPa (0 to 1.45PSI). We have used MPXV5010DP which has dual ports, but a single port sensor can also be used.

Features

Power Supply 5V DC
16 LEDs Display the Liquid Level
Liquid Level Measurement up to 100 cm
2 x 3 mm Mounting Holes
PCB Dimensions 111.71 x 28.89 mm

The MPXV5010DP series piezoresistive transducers are state-of-the-art monolithic silicon pressure sensors designed for a wide range of applications, particularly those employing a microcontroller or microprocessor with A/D inputs. This transducer combines advanced micromachining techniques, thin-film metallization, and bipolar processing to provide an accurate, high-level analog output signal that is proportional to the applied pressure. The axial port has been modified to accommodate industrial-grade tubing.

Arduino Hardware

Arduino Code is available as a download and the code can be uploaded using Arduino UNO. The user will be able to display a 100cm water level, divided by 16 LEDs. The user can map analog value vs 16 LEDs as per requirement.

The Arduino-compatible board contains a few optional components, and the same hardware can be used for other applications as per user requirements.

Applications

Temperature Monitor
Humidity Monitor
Voltage Monitor
LED Light Effects
Gaming
Battery Level Monitor
Current Monitor
Tilt Monitor
Light Monitor

Connections and Other Details

CN1: Pin 1 = Sensor Input Arduino A0, Pin = GND
CN2: Pin 1 = VCC 5V DC, Pin 2 GND
LED D2 to D16 LEDs, Bar-Graph
D1 LED: Power LED
R22, R23: Sensor, Optional (Not used in this application), NTC, LDR, or any other sensor
SW1: No Use, Optional

Schematic

Parts List

BOM	QNTY	REF	DESC	MANUFACTURER	SUPPLIER	SUPPLIER PART NO
1	2	CN1,CN2	2 PIN MALE HEADER PITCH 2.54MM	WURTH	DIGIKEY	732-5315-ND
2	3	C1,C4,C5	0.1uF/16V CERAMIC SMD SIZE 0805	YAGEO/MURATA	DIGIKEY
3	2	C2,C3	22PF/25V CERAMIN DISC THT	YAGEO/MURATA	DIGIKEY
4	1	C6	10uF/25V ELECTROLYTIC	YAGEO/MURATA	DIGIKEY
5	16	D1 to D16	LED GREEN 5MM	KINGBRIGHT	DIGIKEY	754-1263-ND
6	1	PR1	10 TRIMMER POTENTIOMETER	BOURNS	DIGIKEY	3362P-103LF-ND
7	17	R1 to R17	1K OR 470E 5% 1/4W THT	YAGEO/MURATA	DIGIKEY
8	1	R18	10K 5% THT 1/4W	YAGEO/MURATA	DIGIKEY
9	1	R19	1M 5% 1/4W THT	YAGEO/MURATA	DIGIKEY
10	1	R20	1E 5% 1/4W THT	YAGEO/MURATA	DIGIKEY
11	5	SW1,R21,R22,R23,R24	DNP		DIGIKEY	DO NOT INSTALL
12	1	U1	ATMEGA328 DIP28	MICROCHIP	DIGIKEY	ATMEGA328-PU-ND
13	1	Y1	16MHZ	ECS INC	DIGIKEY	X1103-ND
14	1	SOCKET FOR ATMEGA328	28 DIP NARROW SOCKET	ON SHORE TECH	DIGIKEY	ED3050-5-ND
15	1	D17	RED LED 3MM	KINGBRIGHT	DIGIKEY	754-1895-ND