ph2_dupont

pH sensor

The pH sensor is a smart solution for projects that work with measuring the acidity or alkalinity of solutions. It allows for easy connection via dupont wires and instant reading of pH values using the micro:bit in the MakeCode environment. Try measuring the pH of water, compare different liquids or track changes over time while learning the basics of programming, electronics and chemistry in a fun way.
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Description

The pH sensor is a simple input module that allows for precise measurement of the acidity and alkalinity of solutions. It is ideal for water experiments, chemistry experiments or ecological projects. Thanks to the Dupont wires, you can easily connect it to the micro:bit via the MB2 expansion board and use it in the MakeCode environment.

Specifications

Signal conversion board

  • Power voltage: 3,3 - 5,5 V
  • Output voltage: 0 - 3,0 V
  • Probe connector: BNC
  • Signal connector: PH2.0–3P
  • Measurement accuracy: ±0,1 pH at 25°C
  • Module dimensions: 42 × 32 mm (1,66 × 1,26 in)

pH probe

  • Type: Laboratory
  • Measuring range: 0 – 14 pH
  • Temperature range: 5 – 60°C
  • Zero point: 7 0,5 ±
  • Response time: <2 min
  • Internal resistance: < 250 MΩ
  • The cable length: 100 cm
  • Service life: Depends on frequency of use

Components

pH_sensor3
pH sensor

BBC MICRO:BIT V2.2
mb2 photo front
Expansion board MB2

LCD display (IIC)

Dupont wire 20 cm

Connection

pH sensor – micro:bit

  • Blue wire: Connect the sensor signal output to pin P0 on the micro:bit. This pin is used to read the measured values.
  • Red wire: Connect the power wire to the 5V pin. The sensor requires a higher voltage than the standard 3,3V to function properly.
  • Black wire: Connect the ground (GND) to the GND pin of the micro:bit.

LCD display – micro:bit

  • VCC: Connect the 3V3 output of the micro:bit - it provides power to the display.
  • GND: connect to the ground pin of the micro:bit (GND).
  • SCL: connect to the SCL pin of the micro:bit – this is the clock signal for communication over the I2C bus.
  • SDA: connect to the SDA pin of the micro:bit – it is used to transfer data between the micro:bit and the display.

Always make sure the micro:bit is disconnected from power before connecting any devices to avoid damaging the electronics.

ph_dupont

Program

Program for probe V1

For the sensors to function properly, calibration is necessary. The procedure for performing the calibration can be found at manufacturer's website or in the enclosed instructions.

Program for probe V2

For the sensors to function properly, calibration is necessary. The procedure for performing the calibration can be found at manufacturer's website or in the enclosed instructions.

In conjunction with the microbit, the V1 probe can only be used for measurements up to pH < 12 (12 is the maximum value). Exceeding this limit may damage the microbit.

Tasks

Task 1: Measuring the pH of various liquids

Connect the pH sensor according to the diagram and observe the readings on the display. Prepare several different liquids – for example, tap water, lemon juice, soapy water or mineral water. Record their pH and determine which ones are acidic, neutral or basic.

Task 2: Recording pH change over time

Place the probe in a liquid and observe if its pH changes over an hour. For example, in aquarium water or a pot of plant water. Record the readings every 10 minutes.

  • Have there been any pH changes? What could have caused them?
  • Is the environment stable, or does the pH value change significantly?
  • Try to draw a graph of pH changes over time.