Monday, September 27, 2010

Rangkaian Radar Pompa Air (Kontrol Ketinggian Air)

Radar Pompa Air (Kontrol Ketinggian Air)

By means of a Relay, employed to drive a water pump, this circuit provides automatic level control of a water reservoir or well.
Skema Rangkaian Radar Pompa air

  • The two steel rods must be supported by a small insulated (wooden or plastic) board.
  • The circuit can be used also with non-metal tanks, provided a third steel rod having about the same height of the tank will be added and connected to the circuit's negative ground.
The shorter steel rod is the "water high" sensor, whereas the longer is the "water low" sensor. When the water level is below both sensors, IC1C output (pin #10) is low; if the water becomes in contact with the longer sensor the output remains low until the shorter sensor is reached. At this point IC1C output goes high, Q1 conducts, the Relay is energized and the pump starts operating.

Now, the water level begins to decrease and the shorter sensor will be no longer in contact with the water, but IC1C output will be hold high by the signal return to pin #5 of IC1B, so the pump will continue its operation. But when the water level falls below the longer sensor, IC1C output goes low and the pump will stop.

SW1 is optional and was added to provide reverse operation. Switching SW1 in order to connect R3 to pin #11 of IC1D, the pump will operate when the reservoir is nearly empty and will stop when the reservoir is full. In this case, the pump will be used to fill the reservoir and not to empty it as in the default operating mode.

List Component
  • R1,R2: 15K 1/4W Resistors
  • R3: 10K 1/4W Resistor
  • R4: 1K 1/4W Resistor
  • D1: LED
  • D2: 1N4148 Diode
  • IC1: 4001
  • Q1: BC337 NPN Transistor
  • SW1: witch
  • RL1: Relay with SPDT 2A @ 230V switch, Coil Voltage 12V


Wednesday, September 01, 2010

Rangkaian ON OFF Sleep Timer Switch

ON/OFF Sleep Timer Switch

This timer was designed mainly to switch off a portable radio after some time: in this way, one can fall asleep on the sand or on a hammock, resting assured that the receiver will switch off automatically after some time, saving battery costs.

Rangkaian ON OFF Sleep Timer SwitchSkema Rangkaian ON OFF Sleep Timer Switch

R1 and C1 provide a very long time constant. When P2 is momentarily closed, C1 discharges and the near zero voltage at its positive lead is applied to the high impedance inputs of the four gates of IC1 wired in parallel. The four paralleled gate outputs of the IC go therefore to the high state and the battery voltage is available at Q1 Emitter. When P2 is released, C1 starts charging slowly through R1 and when the voltage at its positive lead has reached about half the battery voltage, the IC gate outputs fall to zero, stopping Q1. This transistor can directly drive a portable radio receiver or different devices drawing a current up to about 250mA. Connecting a Relay across the Emitter of Q1 and negative ground, devices requiring much higher voltage and current operation can be driven through its contacts.

Pushing on P2 for 1 to 5 seconds, the circuit starts and then will switch off after about 35 minutes. This time delay can be varied by changing R1 and/or C1 values. P1 will stop the timer if required. LED D1 is optional and can be useful to signal relay operation when the load is placed far from the timer.

List Component
  • R1: 10M 1/4W Resistor
  • R2: 4K7 1/4W Resistor
  • R3: 1K 1/4W Resistor
  • C1: 220µF/ 25V Electrolytic capacitor
  • D1: LED
  • D2: 1N4148
  • IC1: 4011 Quad 2 Input NAND Gate CMos IC
  • Q1: BC337
  • P1,P2: SPST Pushbuttons
  • RL1: 12V Relay

Skema Rangkaian Elektronika