Gravity: Analog Dissolved Oxygen / DO Sensor Meter Kit for Arduino (แท้จาก DFRobot)

INTRODUCTION

This is a dissolved oxygen sensor kit, which is compatible with Arduino microcontrollers. This product is used to measure the dissolved oxygen in water, to reflect the water quality. It is widely applied in many water quality applications, such as aquaculture, environment monitoring, natural science and so on. You may also check Liquid Sensor Selection Guide to get better familiar with our liquid sensor series.

There’s an old saying regarding to keeping fish, “Good fish deserves good water”. Good water quality is very important to the aquatic organisms. Dissolved oxygen is one of the important parameters to reflect the water quality. Low dissolved oxygen in water will lead to difficulty in breathing for aquatic organisms, which may threaten their lives.
We launched a new opensource dissolved oxygen sensor kit, which is compatible with Arduino. This product is used to measure the dissolved oxygen in water, to reflect the water quality. This sensor kit helps you quickly to build your own dissolved oxygen detector.

The probe is a galvanic probe, no need of polarization time, and stay available at any time. The filling solution and membrane cap is replaceable, leading to the low maintenance cost. The signal converter board is plug and play, and has the good compatibility. It can be easily integrated to any control or detecting system.

This product is easy to use with high compatibility. With open-source code and detailed tutorial provided, this product is very suitable for your water projects in detecting the dissolved oxygen concentration for the aquatic organisms.

 

Arduino Dissolved Oxygen (DO) Sensor Connection Diagram

SPECIAL INSTRUCTION:
Due to the International Import and Export Policy, the corrosive solution (acid & alkaline solution) is not allowed to deliver by air transportation. The filling solution is not included in the kit. You have to purchase it from local shop or deploy the solution by yourself, refer to WiKi FAQ-Q4. It can’t work without filling solution! Please be caution with the purchase!

Note:
1. The filling solution is 0.5 mol/L NaOH solution. You need to pour it in the membrane cap before use. Please be caution with the operation because the solution is corrosive. Please wear gloves! If the solution accidentally drops onto the skin, wash your skin with plenty of water immediately.
2. The oxygen permeable membrane in the membrane cap is sensitive and fragile. Be caution when handling with it. Fingernail and other sharp objects should be avoided.
3. The DO sensor will consume a little oxygen during the measurement. Please gently stir the solution and let the oxygen to be distributed evenly in the water.

FEATURES

Dissolved Oxygen Probe：
1. Galvanic probe, no need polarization time
2. Filling solution and membrane cap is replaceable, low maintenance cost

Signal Converter Board：
1. 3.3~5.5V wide-range power supply, compatible with most Arduino microcontroller
2. 0~3.0V analog output, compatible with all microcontrollers with ADC function.
3. Gravity interface, plug and play, easy to use

SPECIFICATION

Dissolved Oxygen Probe

• Type: Galvanic Probe
• Detection Range: 0~20mg/L
• Response Time: Up to 98% full response, within 90 seconds (25℃)
• Pressure Range: 0~50PSI
• Electrode Service Life: 1 year (normal use)
• Maintenance Period: Membrane Cap Replacement Period: 1~2 months (in muddy water); 4~5 months (in clean water) Filling Solution Replacement Period: Once every month
• Cable Length: 2 meters
• Probe Connector: BNC

Signal Converter Board

• Operating Voltage: 3.3~5.5V
• Output Signal: 0~3.0V
• Cable Connector: BNC
• Signal Connector: Gravity Analog Interface (PH2.0-3P)
• Dimension: 42mm * 32mm

DOCUMENTS

• Product WIKI
• More Documents

SHIPPING LIST

• Galvanic Dissolved Oxygen Probe with Membrane Cap x1
• Spare Membrane Cap x1
• Signal Converter Board x1
• Gravity Analog Sensor Cable x1
• Waterproof Gasket x2
• Screw Cap for BNC Connector x1
• Plastic Dropper x2

A1: You can pump air into water for about 20 minutes to saturate the water with oxygen to obtain 100% dissolved oxygen standard liquid.

Q2: How to make zero dissolved oxygen water ? 
A2: Add sodium sulfite (Na2SO3) into water until it is saturated. This can consume all the oxygen in the water to obtain the zero dissolved oxygen liquid. 

Q3: How to store the probe ?
A3:
1. Short time (over night to a week ): dip the probe into purified water or deionized water to prevent the filling solution from evaporating. Disconnect the probe from the main instrument every time when it is not in use. 
2. Long time: (over a week): unscrew the cap from the probe and wash the electrodes core (cathode: platinum, anode: lead) and wash the cap with purified water or deionized water. Dry all the components with tissue. Screw the cap back to the probe without adding any filling solution to prevent the anode from being consumed. Put all the components back into the package.

Q4: How to make 0.5 mol/L NaOH solution?
A4: You need to purchase the NaOH solution first, and add 1~2 drops glycerinum to the NaOH solution for every 100mL. Only by adding the NaOH solution into the probe can it be ready for use. 

Q5: What problems would I usually meet ? How to solve it ?
A5: 
1. If the readings of zero dissolved oxygen liquid is not zero or close to zero, you can polish the cathode of the probe.
2. If the readings is not within normal range or the readings drifts, please check the membrane on the cap. If there are cracks, holes or contaminations on the membrane, please change the cap.

Q6: How to deal with probe electrode corrosion?
A6: You can try to use a brush to clean the rust on it and replace the electrolyte inside. The service life of the electrode is about 1 year. After the service life is exceeded, the entire electrode probe needs to be replaced, which cannot be repaired.