CQRobot Ocean: TDS (Total Dissolved Solids) Meter Sensor Compatible with Raspberry Pi/Arduino Board. for Liquid Quality Analysis Teaching, Scientific Research, Laboratory, Online Analysis, etc.

The overall quality of the product appears to be excellent. In a matter of minutes, I was able to connect it to my Raspberry Pi via an ADC. The configuration instructions on their Wiki page, however, are not very clear. I noticed that other CQRobot products' wiki pages included a zipped file containing the test code, but this one did not. I've been trying to figure out the solution for a few hours now.

Julie Middleton

| Aug 11, 2021

This sensor produces an analog signal that can be measured using an ADC port on an Arduino. If you're using a Raspberry Pi, you'll need an external ADC board, which CQRobot sells. The sample code shows how to use it with Python code. Because we have very hard water (between 690 and 700 ppm), I use a very reliable TDS meter. I took four measurements with the water I had on hand 1) no water, 2) 100% water that has been processed through a reverse osmosis filter, 3) 50% filtered with 50% tap water and% The following are the outcomes: 1) Actual 0 ppm = br>br>br>br>br>br>br>br>br>br>br 0ppm (no water) was measured (0. 00V, 20. Actual 26 ppm = 06 C)br>2) Actual 26 ppm = 06 C)br>3) Actual 26 ppm = 06 C) 63 parts per million (reverse osmosis) (0. 14 v, 21. 3) Actual 343 ppm = 56 C)br> A total of 606 parts per million (ppm) were measured (1. 13V, 17. 4) Actual 691 ppm = 37 C)br>br>br>br>br>br>br>br>b 1720 ppm (hard tap water) was measured (2. 50V, 20. 31 C)br>br>As you can see, the results are not in any way consistent. The PPM is calculated using a third order polynomial in the sample code, but there are no details or explanations provided. In addition, the formula includes a temperature adjustment. This value is set to 25 C by default, which is equivalent to a compensation value of 0. I connected a temperature monitor to the circuit and compensated with actual water temperature. I used a waterproof DS18B20 (Dallas Temperature One Wire) sensor and submerged it in the water samples to do this. br>br>Unfortunately, the outcomes were far from accurate. I can't check to see if the code has any errors because there isn't any documentation on how the device works. I believe there are issues with the code because it will not compile as is. It has a misplaced bracket on the line that looks likebr>br>if (millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis analogSampleTimepoint is a variable that represents the time at which a sample 40U) //read the analog value from the ADC every 40 milliseconds br>br>The bracket at the end of this line is obscured by the comment and must be pushed to the next line on its own. After that, the code will function as it should. The presence of this syntax error indicates that the code has not been thoroughly tested. br>br>I'm giving it three stars because it's well-designed. The cables that come with the board are nice, and the board itself is well-made. Because it's an analog device, I'm guessing the code could be tweaked to get a more precise measurement, either by asking the vendor for more information or by performing a calibration on known samples. br>br>Samples could be created in two ways to calibrate this device. br>br>First option: Using distilled or deionized water, carefully weigh out the salt. For each sample, check the sensor's analog voltage output. The relationship between the weight in grams and the ppm value can be calculated using references found on the Internet. br>Option number two: To make samples with different ppm values, mix different amounts of filtered water and tap water and measure them with a TDS meter. For each sample, read the voltage from the sensor, create a linear or polynomial curve, and use that formula in your code to convert the analog voltage to a ppm value. This method is based on the assumption that you have access to a good TDS meter. br>br>In any case, this is a lot of work and may not be worth it unless you absolutely need a TDS meter integrated into your project.

Karen Boone

| May 02, 2021

This TDS sensor impressed me with its quality of construction. It's also simple to set up; simply connect a few cables and immerse the two metal pins (visible when the white cap is removed). This meter read 100 parts per million for my tap water and 111 parts per million for the coffee I brewed with it. The problem is that I have no idea if this is an accurate measurement because I have no idea how much tap water or coffee made with tap water should weigh. All I can say is that the unit gave me different results. I also notice that the code contains an error that is simple to correct. the code; br>br>br>br>br>br>b if (millis() - millis() - millis() - millis() - millis() - millis() analogSampleTimepoint is a variable that represents the time at which a sample 40U) //every 40 milliseconds, read the analog value from the ADC br>should have the moved from within the comment to the right of the 40U)br>like sobr>if (millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() - millis() analogSampleTimepoint is a variable that represents the time at which a sample 40U) //every 40 milliseconds, read the analog value from the ADCbr>It's also worth noting that you can get the voltage reading by uncommenting the following code: //Serial. br>frombr> br>frombr> br>frombr> br>frombr> "voltage: " print("voltage: " print("voltage: " //Serial is a term that refers to a series of events. averageVoltage,2 = print(averageVoltage,2) = print(averageVoltage,2) = print //Serial is a term that refers to a series of events. print("V "), print("V "), print("V "), print Serial to br>tobr> br>tobr> br>tobr> br>to "voltage: " print("voltage: " print("voltage: " Serial is a term used to describe a series of events that happen in a specific order. averageVoltage,2 = print(averageVoltage,2) = print(averageVoltage,2) = print Serial is a term used to describe a series of events that happen in a specific order. print("V "), print("V "), print("V "), print.

Brady Krause

| Jun 04, 2021

This is an intriguing sensor that can be used to determine the TDS level of liquids. Because it outputs data via an analog signal, and Arduino has an ADC port, it was fairly simple to get started right away. Because the data allows you to read the PPM of liquids, I decided to experiment with a few different inputs, including filtered water from my fridge, rain water, and unfiltered tap water. It was interesting to see the PPMs were a little higher in the unfiltered tap water, but I realized I had no way of knowing if the reading was accurate. I believe this is one of those products that requires some sort of baseline validation mechanism in order to be truly optimized for your needs. Anyone who uses this should get some calibrated TDS solution so they can double-check their calibration for personal projects. br>br>In terms of setup, everything went smoothly. I was able to get the sample code to work without difficulty, and I was able to go from container to test in less than 10 minutes. I'd recommend this product, but only with the caveat that you should double-check how well it calibrates.

Hassan Edwards

| Mar 08, 2021