Introduction: Simple Water Level Detector Using a LM555 in Astable Mode:
- One LM555
- Two 330 Ohms resistors
- One red LED
- One green LED
- One 10 nF capacitor
- One 100 uF capacitor
- One 1 KOhms resistor
- One 100 Ohms resistor
- Wires for connections
- 9 volts battery
- 9 volts battery connector
- Cutting pliers
- Transparent glass
Step 1: Diagram Circuit
1. Connect in the protoboard the following circuit:
Step 2: Connect LM555
2. Connect LM555 terminal 1 to GND.
Step 3: Connect LM555 Terminals
3. Connect LM555 terminals 4 and 8 to the 9 volts battery positive terminal.
Step 4: Connect LM555 Terminals
4. Connect LM555 terminals 2 and 6.
Step 5: Connect
5. Connect one terminal of R1 to LM555 terminal 7.
6. The other terminal of R1 should be left free for one of the open terminals connection.
Step 6: Connect
7. Connect R2 between LM555 terminals 6 and 7.
Step 7: Connect
8. Connect the other terminal of R2 to the possitive terminal of C1.
Step 8: Connect
9. Connect the negative terminal of C1 to GND.
Step 9: Connect LM555 Terminal
10. Connect LM555 terminal 5 to a 10 nF capacitor.
Step 10: Free Terminal
11. Then connect the free terminal of the 10 nF to GND.
Step 11: Connect LM555
12. Connect LM555 terminal 3 to R4.
Step 12: Connect
13. Connect the negative terminal of D2 to R4.
Step 13: Connect
14. Connect the positive terminal of D2 to the 9 volts battery positive terminal.
Step 14: Connect
15. Connect R3 to GND.
Step 15: Connect the Free Terminal
16. Connect the free terminal of R3 to the negative terminal of D1.
Step 16: Connect D1 Positive Terminal
17. Connect D1 positive terminal to the 9 volts battery positive terminal.
Step 17: Connect
18. Connect the free R1 terminal to one of the open terminals.
Step 18: Place
19. Place the other end of the terminal with tape at a specified level of the glass.
Step 19: Place the Other
20. Place the other open terminal with tape at the bottom of the glass.
Step 20: Connect the Other End
21. Connect the other end of the open terminal to the positive terminal of the 9 volts battery.
Step 21: Turn the Circuit On
22. Turn the circuit on by connecting the 9 volts battery.
Step 22: The Green LED
23. The green LED will turn on indicating the circuit/device is on.
Step 23: The Red LED Will Start to Flash
24. Pour water into the glass and, once the water level reaches the higher open terminal, the red LED will start to flash.
When the open terminals aren’t closed the red LED D2 will be off. It is intended for the open terminals to be closed with a determined water level. Once the water lever reaches the desired quantity, the water will close the open terminals (or this part of the circuit) and, as the LM555 is configured in Astable mode, the LM555 output (terminal 3) will send a continuous squared wave form into D2 which will make the red LED to flash at a determined frequency. The frecuency of the squared wave is determined by the values of R1, R2, C1 and the impedance of the water.