Grove - 2-Coil Latching Relay

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Introduction This module is based on 2-Coil Latching Relay. Contrast to the ordinary relay, this latching relay does not need continuous power to keep the state, only a rising/falling pulse is needed to change the work state. Even the power can be removed when the work state do not need to change, making this module especially suitable for low-power projects.


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FeatureGrove Connector Low power consumption Dual Switch Specification

         Item  Min  Typical  Max  Unit  

Working Voltage 4.7 5.0 5.3 VDC Set/Reset Voltage(Max) 4.0 VDC Coil Resistance 151 167 183 Ω Switching Voltage(Max) 35VAC/35VDC / Switching Current(Max) 3 A Set Time(Latching) 4.5(max) ms Reset Time(Latching) 3.5(max) ms

UsageWith ArduinoThe latching relay only draws power during the changing of state. A rising/falling voltage pulse on the signal pin changes it's working state. This is very useful in situations where energy efficiency is important, and also in situations where you need the relay to remember its state.

Let's begin to use it.

Connect the module to D3 port of Grove - Base Shield. The relay hold in "set" status(Comm and NO connected) in default, when there is a rising edge on the SIG pin. It turns the "reset" state(Comm and NC connected). The reference code as show below:

  1. define LatchingRelay 3

void setup() { pinMode(LatchingRelay,OUTPUT);

digitalWrite(LatchingRelay,LOW); delay(1000); digitalWrite(LatchingRelay,HIGH); delay(1000);

} void loop() {

}The relay hold in "reset" status(Comm and NC Connected), when there is a falling edge on the SIG pin. It turns the "set" state(Comm and NO connected). The reference code as show below:

  1. define LatchingRelay 3

void setup() { pinMode(LatchingRelay,OUTPUT);

digitalWrite(3,HIGH); delay(1000); digitalWrite(3,LOW); delay(1000); } void loop() {

}This module consumes little power when working state doesn't change. After setting the relay state, you do not need to supply power for the Latching Relay any more, which makes it especially low power consumption.


Note:

1) Relay is on the "reset" status when being released from stock.

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2) The two-way relay are controlled at the same time. 3) The NO(NC) indicator will flash once when switch to "set"("reset") status. With Raspberry Pi 1.You should have got a raspberry pi and a grovepi or grovepi+. 2.You should have completed configuring the development enviroment, otherwise follow here. 3.Connection


Plug the sensor to grovepi socket D4 by using a grove cable.

4.Navigate to the demos' directory:


  cd yourpath/GrovePi/Software/Python/

To see the code

  nano grove_2_coil_latching_relay.py   # "Ctrl+x" to exit #

import time import grovepi

  1. Connect the Grove 2-Coil Latching Relay to digital port D4
  2. SIG,NC,VCC,GND

relay = 4

grovepi.pinMode(relay,"OUTPUT")

while True:

   try:
       # switch on for 5 seconds
       grovepi.digitalWrite(relay,1)
       print "on"
       time.sleep(5)
       # switch off for 5 seconds
       grovepi.digitalWrite(relay,0)
       print "off"
       time.sleep(5)
   except KeyboardInterrupt:
       grovepi.digitalWrite(relay,0)
       break
   except IOError:
       print "Error"

Resource

File:Latching Relay Datesheet.pdf