Food & Water Salinity Tester Meter circuit

Here is a simple salinometer or salinity tester. Why should use it? You know eating too much salinity not good for health.

But the recognition of salinity may differ. And familiarity with salty flavors. Causing us to eat more salty foods without knowing ourselves.

We may buy a new one of a salt tester. But creating it is pride. And the use of electronic learning time that is very valuable.

LED Electronic Food Salt Salinity Tester Pen-min

Cr: Photo by Matefield

Note: salinometer is Electronic Test types of equipment for measure salt level.


The circuit ideals

Circuit designers have interesting ideas. Unfortunately, if you do not learn it. Of course, keep it simple first.

We know saltwater has resistance same as general water. If we apply a constant current through saltwater and resistors. It causes the differential voltage across the input. So, we use the comparator circuit by an op-amp IC. It is LED Display Level Meters.

The input is sensor or probe in the water or food. Then, Show amount of salinity level with 3 different LED colors, Much, appropriate, less.

How the circuit works

salinity tester meter circuit

The circuit ready running. When we dip the probe into the solution or food.

Then, press switch-S1. And, IC1/1(LM324) amplifies a differential signal.

Next, the voltage output at pin 1.

Because quantities resistance or conductivity of the solution foods has salt component is measured through the probe.

Non salinity

If water or foods with a little salt as an ingredient. The resistance is quite high. So, low current to flow through it.

The voltage comparator circuit has output voltage at pin1 is low voltage. As a result, output at pin 14, pin 8 and pin 7 of IC1/4, IC1/3 and IC1/2(LM324) have all high state. Makes the LED5, LED4, and LED3 not glow.

Find Proper salinity

Water or food, that have salt is very complemented. Resistance is relatively low.
Current to flow through much makes the output signal at pin 1 much into the voltage comparator circuit.

As a result of the output at pin 14, pin 8 or pin 7 of IC1/4, IC1/3 and IC1/2 have stated are high only one or all.

Makes LED5, LED4 or LED3 in order to light up.

LM324 pinoutSee: 4 op-amps inside LM324

Three salinity level

Low level—Use LED5 is yellow. If it lights up to indicate by the amount of low salt in food or water.

Enough level—use LED4 is green. It shows a suitable level of salt in food.

High level—Use LED3 will light red. When the user is represented by the amount of salt in food or water is too much.

Customization and applications

The LED2 and LED1 will light the Showing while running all the time.

By the anode pin of LED2 will have setting voltage about 3.2 Volts. They determined from resistors R7, R8 and R9.

The anode of LED1 will have voltage about 1.6 volts is a constant voltage provides to probe. To use for setting a voltage at VR1.

To determine the operating point of the circuit can be adjusted by changing the resistor VR1 or R7, R8, and R9.

Setting the project may try to dip the probe into water and adjust the VR1 and the LED goes out all.

Or Try dipping the probe into the solution containing salt component.

Then, adjust VR1 to LED5, LED4 or LED3 is lit up by the sort in order of salt.

The probe is made of a conductive metal. Or 6.3-mm mono Jack uses it. Connect the power cord to the point probe.

The test should be dipped in a solution of food. And then wait for about half a minute. The accuracy of the LED display of each test.

Do not forget to press the switch S1.

Let’s build this circuit

This circuit you can assemble them onto Universal PCB Board because simple and cheap.

Appropriate salinity levels in food

How much salt per day is healthy?
The American Heart Association recommends no more than 2,300 milligrams (mg) a day.

Eating very salty foods. Will cause many diseases such as high blood pressure and chronic kidney disease. Which is a top-level health problem Of people around the world. From studies and data collection found that most people with high blood pressure, up to 1 in 4 adults.

By the way, I care about you.


You may like this:
Simple high water level alarm
Automatic water level controller circuits

Related Posts


I always try to make Electronics Learning Easy.

Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments
Close Menu