💤 Deep Sleep

Using low-power mode on your DNS Driveby Kit 🔋

Deep sleep mode allows your wardriving kit to preserve energy when the device isn’t in motion. Your kit automatically shuts off after a couple minutes of inactivity, and wakes up when again when motion is detected!

This lets you attach the kit to a car, a cat, or other similar object for motion-triggered tracking.

Parts #

Other SW-180xxP switches will work, but part 18010P is the most sensitive

How It Works #

The ESP8266 can be placed into a timed deep sleep using the builtinESP.deepSleep(uS) function, or indefinitely with ESP.deepSleep(0). The latter sleeps until the ESP8266 is reset by grounding the RST pin.

Using a shake sensor allows us to short the RST pin to GND when motion is detected without needing any code - but we don’t want to accidentally trigger resets while driving.

We solve this by using digital logic that prevents the RST pin from grounding while the ESP8266 is powered up. This simple circuit uses transistors in a NOT Gate configuration to prevent the RST from grounding if a HIGH current is detected from pin D0. Otherwise, when the ESP8266 is in sleep mode (no current from D0), the NOT Gate allows the circuit to reset.

Code #

Try this really basic Arduino sketch to try this feature out:

void setup() {

  // start Serial
  Serial.begin(115200);
  Serial.println("ESP8266 Started!");

  // set pin D0 HIGH on startup
  pinMode(D0, OUTPUT);
  digitalWrite(D0, HIGH);

  // sleep after 15 seconds
  Serial.println("Sleeping in 10 seconds!");

  unsigned long ptime = millis(); unsigned long ctime = millis();
  while (ctime-ptime <15000) { 
    ctime = millis();
    Serial.println(ctime/1000);
  }

  // SLEEPY TIME
  ESP.deepSleep(0);

}

void loop() {
  //
}