I am extremely new to electronics and stuff, I was trying to design a water level indicator.
In Proteus, all the LED indications are working perfectly, but for some reason my buzzer won't work.
\$\begingroup\$
\$\endgroup\$
9
-
\$\begingroup\$ So your question is? \$\endgroup\$– Marcus MüllerCommented Jun 18, 2017 at 5:02
-
\$\begingroup\$ Why that buzzer is not working \$\endgroup\$– Danial AhmedCommented Jun 18, 2017 at 5:04
-
\$\begingroup\$ Well, we don't know your buzzer, so it'll be your task to check whether it works without your circuit and narrow down the problem. \$\endgroup\$– Marcus MüllerCommented Jun 18, 2017 at 5:05
-
2\$\begingroup\$ So this is a simulated buzzer, not a real one. It is described as a "DC buzzer" in your picture - perhaps polarity matters - try exchanging the connections to the buzzer. \$\endgroup\$– Peter BennettCommented Jun 18, 2017 at 5:46
-
2\$\begingroup\$ R1,2,3 are too low. Q1 should have one of those too. What is the loop of conductor in the bottom of the water tank supposed to be doing? Without Q1's base resistor, I would expect its base-emitter diode junction to load the battery to 0.7v, or to blow the transistor up. With the resistor, I would expect all LEDs and buzzer to be 'on'. Hint, 'didn't work' is not a problem description. 'Stays on all the time', or 'drops battery voltage to 0.7v', is a problem description that tells us what it is doing, aiding debugging. \$\endgroup\$– Neil_UKCommented Jun 18, 2017 at 6:50
|
Show 4 more comments
1 Answer
\$\begingroup\$
\$\endgroup\$
3
First of all
I'm going to talk about the power phase of your circuit. Look at the picture below 
This means that all the red lined tracks are short circuited (connected); thus all these npn transistors will work on their ON State which means; green, yellow, red, and the buzzer are going to be pulled up (ON State). So you have to add a switching device to determine on which level you have to power up each LED and when the buzzer will be pulled up also. And in your case you can use water level sensor.
Secondly
You have to determine the working mechanism of your circuit, which means when the level is going to rise from the green state to the yellow state, do you want the green LED to be still pulled up or you want to turn it off? this situation is going to determine if you have to add another components to your circuit or not.
Consider that you have decided to turn the green LED off (in our case), you have to make a truth table for cases you wish to light each LED On individually. We have three input levels and a buzzer. we will consider that the buzzer will be pulled up with the red LED. Also you have to know that when the level exceeds the green level and starts to enter in the yellow region you still have your green level sensor pulled up since water is rising from level to level. This understanding makes us familiar with cases we want the LEDs to be turned on and we also are able to draw our truth table.
You will find that the green LED will only turned ON when the green level sensor is ON and the yellow and red one is Off.
The yellow LED is ON when green and yellow sensor are ON and the red one is Off
The red LED and buzzer are both ON when green, yellow, and red are all ON.
-
\$\begingroup\$ Thank you for your reply. "this situation is going to determine if you have to add another components to your circuit or not.". I want it to remain on. \$\endgroup\$ Commented Jun 25, 2017 at 17:52
-
\$\begingroup\$ So when the Yellow sensor reads a signal "water has reached its level" the Yellow LED is forced to be on, and note that the green sensor still reads a signal that water is available, due to water emerges from bottom to top sequentially, I mean from green to yellow to red. \$\endgroup\$ Commented Jun 26, 2017 at 19:22
-
\$\begingroup\$ You dont have to add any other components except level sensors to enable LED lights according to the actual water level \$\endgroup\$ Commented Jun 28, 2017 at 22:15