The Gravity Analog Dissolved Oxygen Level Sensor for Arduino from Graylogix is one of the most popular and best Dissolved Oxygen Sensors that are available in the market. The Analog dissolved oxygen sensor kit from Graylogix is compatible with Arduino, ESP8266, ESP32, STM32 microcontrollers & Raspberry Pie. The 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, etc.
Dissolved Oxygen Calculation:
Dissolved oxygen concentration levels may be expressed as milligrams per liter (mg/L) or parts per million (ppm). 1 mg/L is equal to 1 ppm. Dissolved oxygen saturation is expressed as a percentage. The D O Sensor kit has a signal converter board with a BNC connector which can directly be connected to Galvanic Probe. The Signal converter board basically amplify the minor voltage difference to a readable signal that can be detected by Arduino. The signal converter board is plug and play and has good compatibility.
The sensor tip should be covered by a membrane cap where a solution needs to be filled. (Check out the video for more details on assembling the DO membrane and filling the membrane cap with KCL solution) The oxygen-permeable membrane in the membrane cap is sensitive and fragile. Use caution when handling it. It can be easily integrated into any control or detecting system.
Note: Fingernails and other sharp objects should be avoided in order to protect the DO membrane from getting damaged.
Preparing of the Dissolved Oxygen Level Sensor Probe:
For a new dissolved oxygen probe, 7.5% KCL solution should be added into the membrane cap first as the filling solution. To do that follow the following steps.
- Remove the membrane crown,
- Place the DO membrane on the cap and fix the crown to the electrolyte tube covering one side of the membrane.
- Make sure that there is no wrinkles in the membrane and that is does not get punctured or damaged.
- Unscrew the membrane cap from the probe and fill about 2/3 volume of the cap with KCL solution.
- Make sure the probe is in a vertical position with respect to the horizontal plane.
- Carefully screw the cap back to the probe. It would be nice if a little bit of solution overflows out of the cap to ensure the probe is fully filled with KCL solution and there are no air bubbles in it.
- 7.5% KCL solution acts as good electrolyte in DO Probe. Presence of any other salt in the electrolyte solution may damage the probe.
- The electrode tube should not contain any air bubble, if it is present it will cause fluctuations in the readings.
Check out the data sheet for the calibration process and sample code for Arduino.
Technical Specifications of Dissolved Oxygen Level Sensor:
|Range||0 to 20.0 ppm|
|Accuracy||+/- 0.2 ppm to +/- 1 count|
|DO Sensor||Amperometric Gold/Silver Membrane type|
|Power||9 Volts battery|
|DO Electrode||1 No|
|Signal Converter Board||1 No|
|Instruction Manual||1 No|
|DO Membranes||1 Set (4 Nos.)|
|Potassium Chloride Crystals||2 grams|
More details about D O Sensor can be found from How2Electronics.com