Rain Gauge

created by hek , updated

Here you will learn how to make your own wireless "tipping bucket" rain sensor. You can either print the 3D model yourself or MySensorize some cheap tipping bucket hardware found below.

The principle behind this is quite simple; When it rains a funnel collects water into two tiny "buckets". When one bucket is full it tips out the water and the second bucket starts to fill up. Each tip is registered and this data is transmitted to your controller.

By measuring the funnel opening and bucket size you can calculate the amount of rain that has fallen. Need help calculate your own funnel construction? Have a look here.

The DIY tipping bucket 3D model created by BulldogLowell can be found here.

The example also contains some optional light, humidity and temperature sensors that can be removed if you want to keep it simple.

Big thanks to BulldogLowell and PeteWill for creating and documenting this great project. You can read the background story on the forum.

Demonstration

A video showing how to setup your own rain gauge.

Wiring Things Up

Parts

  • Prototype Universal Printed Circuit Boards (PCB)
  • NRF24L01 Radio
  • Arduino (Pro Mini was used in the example video)
  • FTDI USB to TTL Serial Adapter (if using a Pro Mini)
  • Rain Gauge (Tipping bucket)
  • Capacitors (10uf and .1uf)
  • 3.3v voltage regulator
  • Resistor (270 Ω)
  • Female Dupont Cables
  • Male Dupont Cables
  • Male Pin Header Connector Strip
  • Female Pin Header Connector Strip
  • LED
  • 2 Pole 5mm Pitch PCB Mount Screw Terminal Block
  • 22-24 gauge wire or similar (I used Cat5/Cat6 cable)
  • DHT-22 (optional) - humidity/temp sensor
  • BH1750 (optional) - light sensor

Example

/mysensors/MySensorsArduinoExamples/examples/RainGauge/RainGauge.ino
Last updated by petewill, 16 Oct 2016, "Update RainGauge example to be compatible with v2.0"

/*
 Arduino Tipping Bucket Rain Gauge

 April 26, 2015

 Version 2.0

 Arduino Tipping Bucket Rain Gauge

 Utilizing a tipping bucket sensor, your Vera home automation controller and the MySensors.org
 gateway you can measure and sense local rain.  This sketch will create two devices on your
 Vera controller.  One will display your total precipitation for the last 5 days.  The other, 
 a sensor that changes state if there is recent rain (up to last 120 hours)  above a threshold.  
 Both these settings are user definable.

 There is a build overview video here: https://youtu.be/1eMfKQaLROo

 This sketch features the following:

 * Allows you to set the rain threshold in mm
 * Allows you to determine the tripped indicator window up to 120 hours.
 * Displays the last 5 days of rain in Variable1 through Variable5
   of the Rain Sensor device
 * Configuration changes to Sensor device updated every hour
 * Should run on any Arduino
 * Will retain Tripped/Not Tripped status and data in a power interruption, saving small amount
   of data to EEPROM (Circular Buffer to maximize life of EEPROM)
 * LED status indicator
 * Optional Temp/Humidity (DHT-22 or DHT-11) and Light LUX (BH1750) sensors. To use, uncomment
   #define DHT_ON  and/or #define LUX_ON
 * Optionally send total accumulation of each day's rainfall or send only individual days rainfall totals.
   Uncomment #define USE_DAILY to display individual daily rainfall.  If it is commented out it will display
   a cumulative total rainfall (day4 = day1+day2+day3+day4 etc)

 by @BulldogLowell and @PeteWill for free public use

 */

//#define MY_DEBUG // Enable MySensors debug prints to serial monitor

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

//#define MY_NODE_ID 7 //uncomment this line to assign a static ID

#include <math.h>
#include <TimeLib.h>
#include <MySensors.h>

#define SKETCH_NAME "Rain Gauge"
#define SKETCH_VERSION "2.0"

#define DWELL_TIME 40  // this allows for radio to come back to power after a transmission, ideally 0 

//#define DEBUG_ON  // Rain gauge specific debug messages. 
#define DHT_ON // uncomment out this line to enable DHT sensor
#define LUX_ON // uncomment out this line to enable BH1750 sensor
//#define USE_DAILY // Uncomment to display individual daily rainfall totals in the variables sent to your controller. If it's commented it will add each day to the next for a cumulative total.

#define TIP_SENSOR_PIN 3
#define CALIBRATE_FACTOR 60 // amount of rain per rain bucket tip e.g. 5 is .05mm
#define DHT_LUX_DELAY 300000  //Delay in milliseconds that the DHT and LUX sensors will wait before sending data

#define CHILD_ID_RAIN_LOG 3  // Keeps track of accumulated rainfall
#define CHILD_ID_TRIPPED_INDICATOR 4  // Indicates Tripped when rain detected
#define EEPROM_BUFFER_LOCATION 0  // location of the EEPROM circular buffer
#define E_BUFFER_LENGTH 240
#define RAIN_BUCKET_SIZE 120

#ifdef  DEBUG_ON
  #define DEBUG_PRINT(x)   Serial.print(x)
  #define DEBUG_PRINTLN(x) Serial.println(x)
  #define SERIAL_START(x)  Serial.begin(x)
  #else
  #define DEBUG_PRINT(x)
  #define DEBUG_PRINTLN(x)
  #define SERIAL_START(x)
#endif
//
MyMessage msgRainRate(CHILD_ID_RAIN_LOG, V_RAINRATE);
MyMessage msgRain(CHILD_ID_RAIN_LOG, V_RAIN);
//
MyMessage msgRainVAR1(CHILD_ID_RAIN_LOG, V_VAR1);
MyMessage msgRainVAR2(CHILD_ID_RAIN_LOG, V_VAR2);
MyMessage msgRainVAR3(CHILD_ID_RAIN_LOG, V_VAR3);
MyMessage msgRainVAR4(CHILD_ID_RAIN_LOG, V_VAR4);
MyMessage msgRainVAR5(CHILD_ID_RAIN_LOG, V_VAR5);
//
MyMessage msgTripped(CHILD_ID_TRIPPED_INDICATOR, V_TRIPPED);
MyMessage msgTrippedVar1(CHILD_ID_TRIPPED_INDICATOR, V_VAR1);
MyMessage msgTrippedVar2(CHILD_ID_TRIPPED_INDICATOR, V_VAR2);
//
#ifdef DHT_ON
  #include <DHT.h>
  #define CHILD_ID_HUM 0
  #define CHILD_ID_TEMP 1
  #define HUMIDITY_SENSOR_DIGITAL_PIN 8
  DHT dht;
  float lastTemp;
  float lastHum;
  bool metric = true;
  MyMessage msgHum(CHILD_ID_HUM, V_HUM);
  MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);
#endif
//
#ifdef LUX_ON
  //BH1750 is connected to SCL (analog input A5) and SDA (analog input A4)
  #include <BH1750.h>
  #include <Wire.h>
  #define CHILD_ID_LIGHT 2
  BH1750 lightSensor;
  MyMessage msg(CHILD_ID_LIGHT, V_LIGHT_LEVEL);
  unsigned int lastlux;
  uint8_t heartbeat = 10; //Used to send the light lux to gateway as soon as the device is restarted and after the DHT_LUX_DELAY has happened 10 times
#endif
unsigned long sensorPreviousMillis;
int eepromIndex;
int tipSensorPin = 3; // Pin the tipping bucket is connected to. Must be interrupt capable pin
int ledPin = 5; // Pin the LED is connected to.  PWM capable pin required
#ifdef DEBUG_ON
unsigned long dataMillis;
unsigned long serialInterval = 600000UL;
#endif
const unsigned long oneHour = 3600000UL;
unsigned long lastTipTime;
unsigned long lastRainTime; //Used for rainRate calculation
unsigned int rainBucket [RAIN_BUCKET_SIZE] ; /* 24 hours x 5 Days = 120 hours */
unsigned int rainRate = 0;
uint8_t rainWindow = 72;         //default rain window in hours.  Will be overwritten with msgTrippedVar1.
volatile int wasTippedBuffer = 0;
int rainSensorThreshold = 50; //default rain sensor sensitivity in hundredths.  Will be overwritten with msgTrippedVar2.
uint8_t state = 0;
uint8_t oldState = 2; //Setting the default to something other than 1 or 0
unsigned int lastRainRate = 0;
int lastMeasure = 0;
bool gotTime = false;
uint8_t lastHour;
uint8_t currentHour;
//
void presentation()  {
  // Register all sensors to gw (they will be created as child devices)
  sendSketchInfo(SKETCH_NAME, SKETCH_VERSION);
  wait(DWELL_TIME);
  present(CHILD_ID_RAIN_LOG, S_RAIN);
  wait(DWELL_TIME);
  present(CHILD_ID_TRIPPED_INDICATOR, S_MOTION);
  wait(DWELL_TIME);

#ifdef DHT_ON
  present(CHILD_ID_HUM, S_HUM);
  wait(DWELL_TIME);
  present(CHILD_ID_TEMP, S_TEMP);
  wait(DWELL_TIME);
#endif


#ifdef LUX_ON
  present(CHILD_ID_LIGHT, S_LIGHT_LEVEL);
#endif

  DEBUG_PRINTLN(F("Sensor Presentation Complete"));
}

void setup()
{
  #ifndef MY_DEBUG
  SERIAL_START(115200);  //Start serial if MySensors debugging isn't enabled
  #endif
  //
  // Set up the IO
  pinMode(TIP_SENSOR_PIN, INPUT_PULLUP);
  attachInterrupt (digitalPinToInterrupt(TIP_SENSOR_PIN), sensorTipped, FALLING);  // depending on location of the hall effect sensor may need CHANGE
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, HIGH);
  //
  //Sync time with the server
  //
  unsigned long functionTimeout = millis();
  while (timeStatus() == timeNotSet && millis() - functionTimeout < 30000UL)
  {
    requestTime();
    DEBUG_PRINTLN(F("Getting Time"));
    wait(1000); // call once per second
    DEBUG_PRINTLN(F("."));
  }
  currentHour = hour();
  lastHour = hour();
  //
  //retrieve from EEPROM stored values on a power cycle.
  //
  bool isDataOnEeprom = false;
  for (int i = 0; i < E_BUFFER_LENGTH; i++)
  {
    uint8_t locator = loadState(EEPROM_BUFFER_LOCATION + i);
    if (locator == 0xFE)  // found the EEPROM circular buffer index
    {
      eepromIndex = EEPROM_BUFFER_LOCATION + i;
      DEBUG_PRINT(F("EEPROM Index "));
      DEBUG_PRINTLN(eepromIndex);
      //Now that we have the buffer index let's populate the rainBucket[] with data from eeprom
      loadRainArray(eepromIndex);
      isDataOnEeprom = true;
      break;
    }
  }
  //
  if (!isDataOnEeprom) // Added for the first time it is run on a new Arduino
  {
    DEBUG_PRINTLN(F("I didn't find valid EEPROM Index, so I'm writing one to location 0"));
    eepromIndex = EEPROM_BUFFER_LOCATION;
    saveState(eepromIndex, 0xFE);
    saveState(eepromIndex + 1, 0xFE);
    //then I will clear out any bad data
    for (int i = 2; i <= E_BUFFER_LENGTH; i++)
    {
      saveState(i, 0x00);
    }
  }
  #ifdef DEBUG_ON
  dataMillis = millis();
  #endif
  lastTipTime = millis(); 
  //
  request(CHILD_ID_TRIPPED_INDICATOR, V_VAR1);
  wait(DWELL_TIME);
  request(CHILD_ID_TRIPPED_INDICATOR, V_VAR2);
  wait(DWELL_TIME);
  //
#ifdef DHT_ON
  dht.setup(HUMIDITY_SENSOR_DIGITAL_PIN);
  metric = getConfig().isMetric;
  wait(DWELL_TIME);
#endif
  //
#ifdef LUX_ON
  lightSensor.begin();
#endif
  //
  transmitRainData(); //Setup complete send any data loaded from eeprom to gateway
}

void loop()
{
  if (state)
  {
    prettyFade();  // breathe if tripped
  }
  else
  {
    slowFlash();   // blink if not tripped
  }
#ifdef DEBUG_ON  // Serial Debug Block
  if ( (millis() - dataMillis) >= serialInterval)
  {
    for (int i = 24; i <= 120; i = i + 24)
    {
      updateSerialData(i);
    }
    dataMillis = millis();
  }
#endif
  //
  // let's constantly check to see if the rain in the past rainWindow hours is greater than rainSensorThreshold
  //
  int measure = 0; // Check to see if we need to show sensor tripped in this block
  for (int i = 0; i < rainWindow; i++)
  {
    measure += rainBucket [i];
    if (measure != lastMeasure)
    {
      //      DEBUG_PRINT(F("measure value (total rainBucket within rainWindow): "));
      //      DEBUG_PRINTLN(measure);
      lastMeasure = measure;
    }
  }
  //
  state = (measure >= (rainSensorThreshold * 100));
  if (state != oldState)
  {
    send(msgTripped.set(state));
    wait(DWELL_TIME);
    DEBUG_PRINT(F("New Sensor State... Sensor: "));
    DEBUG_PRINTLN(state ? "Tripped" : "Not Tripped");
    oldState = state;
  }
  //
  unsigned long tipDelay = millis() - lastRainTime;
  if (wasTippedBuffer) // if was tipped, then update the 24hour total and transmit to Vera
  {
    DEBUG_PRINTLN(F("Sensor Tipped"));
    DEBUG_PRINT(F("rainBucket [0] value: "));
    DEBUG_PRINTLN(rainBucket [0]);
    send(msgRain.set((float)rainTotal(currentHour) / 100, 1)); //Calculate the total rain for the day
    wait(DWELL_TIME);
    wasTippedBuffer--;
    rainRate = ((oneHour) / tipDelay);
    if (rainRate != lastRainRate)
    {
      send(msgRainRate.set(rainRate, 1));
      wait(DWELL_TIME);
      DEBUG_PRINT(F("RainRate= "));
      DEBUG_PRINTLN(rainRate);
      lastRainRate = rainRate;
    }
    lastRainTime = lastTipTime;
  }
  //
  currentHour = hour();
  if (currentHour != lastHour)
  {
    DEBUG_PRINTLN(F("One hour elapsed."));
    send(msgRain.set((float)rainTotal(currentHour) / 100, 1)); // send today's rainfall
    wait(DWELL_TIME);
    saveState(eepromIndex, highByte(rainBucket[0]));
    saveState(eepromIndex + 1, lowByte(rainBucket[0]));
    DEBUG_PRINT(F("Saving rainBucket[0] to eeprom. rainBucket[0] = "));
    DEBUG_PRINTLN(rainBucket[0]);
    for (int i = RAIN_BUCKET_SIZE - 1; i >= 0; i--)//cascade an hour of values back into the array
    {
      rainBucket [i + 1] = rainBucket [i];
    }
    request(CHILD_ID_TRIPPED_INDICATOR, V_VAR1);
    wait(DWELL_TIME);
    request(CHILD_ID_TRIPPED_INDICATOR, V_VAR2);
    wait(DWELL_TIME);
    rainBucket[0] = 0;
    eepromIndex = eepromIndex + 2;
    if (eepromIndex > EEPROM_BUFFER_LOCATION + E_BUFFER_LENGTH)
    {
      eepromIndex = EEPROM_BUFFER_LOCATION;
    }
    DEBUG_PRINT(F("Writing to EEPROM.  Index: "));
    DEBUG_PRINTLN(eepromIndex);
    saveState(eepromIndex, 0xFE);
    saveState(eepromIndex + 1, 0xFE);
    requestTime(); // sync the time every hour
    wait(DWELL_TIME);
    transmitRainData();
    rainRate = 0;
    send(msgRainRate.set(rainRate, 1));
    wait(DWELL_TIME);
    DEBUG_PRINTLN(F("Sending rainRate is 0 to controller"));
    lastHour = hour();
  }
  if (millis() - sensorPreviousMillis > DHT_LUX_DELAY)
  {
    #ifdef DHT_ON  //DHT Code
      doDHT();
    #endif
    #ifdef LUX_ON
      doLUX();
    #endif
    sensorPreviousMillis = millis();
  }
}
//
#ifdef DHT_ON
void doDHT(void)
{
  float temperature = dht.getTemperature();
    if (isnan(temperature)) 
    {
      DEBUG_PRINTLN(F("Failed reading temperature from DHT"));
    } else if (temperature != lastTemp) 
    {
      lastTemp = temperature;
      if (!metric) 
      {
        temperature = dht.toFahrenheit(temperature);
      }
      send(msgTemp.set(temperature, 1));
      wait(DWELL_TIME);
      DEBUG_PRINT(F("Temperature is: "));
      DEBUG_PRINTLN(temperature);
    }
    float humidity = dht.getHumidity();;
    if (isnan(humidity)) 
    {
      DEBUG_PRINTLN(F("Failed reading humidity from DHT"));
    } else if (humidity != lastHum) 
    {
      lastHum = humidity;
      send(msgHum.set(humidity, 1));
      wait(DWELL_TIME);
      DEBUG_PRINT(F("Humidity is: "));
      DEBUG_PRINTLN(humidity);
    }
}
#endif
//
#ifdef LUX_ON
void doLUX(void)
{
  unsigned int lux = lightSensor.readLightLevel();// Get Lux value
  DEBUG_PRINT(F("Current LUX Level: "));
  DEBUG_PRINTLN(lux);
  heartbeat++;
  if (lux != lastlux || heartbeat > 10) 
  {
    send(msg.set(lux));
    lastlux = lux;
  }
  if (heartbeat > 10) 
  {
    heartbeat = 0;
  }
}
#endif
//
void sensorTipped()
{
  unsigned long thisTipTime = millis();
  if (thisTipTime - lastTipTime > 100UL)
  {
    rainBucket[0] += CALIBRATE_FACTOR; // adds CALIBRATE_FACTOR hundredths of unit each tip
    wasTippedBuffer++;
  }
  lastTipTime = thisTipTime;
}
//
int rainTotal(int hours)
{
  int total = 0;
  for ( int i = 0; i <= hours; i++)
  {
    total += rainBucket [i];
  }
  return total;
}

#ifdef DEBUG_ON
void updateSerialData(int x)
{
  DEBUG_PRINT(F("Rain last "));
  DEBUG_PRINT(x);
  DEBUG_PRINTLN(F(" hours: "));
  float tipCount = 0;
  for (int i = 0; i < x; i++)
  {
    tipCount = tipCount + rainBucket [i];
  }
  tipCount = tipCount / 100;
  DEBUG_PRINTLN(tipCount);
}
#endif

void loadRainArray(int eValue) // retrieve stored rain array from EEPROM on powerup
{
  for (int i = 1; i < RAIN_BUCKET_SIZE; i++)
  {
    eValue = eValue - 2;
    if (eValue < EEPROM_BUFFER_LOCATION)
    {
      eValue = EEPROM_BUFFER_LOCATION + E_BUFFER_LENGTH;
    }
    DEBUG_PRINT(F("EEPROM location: "));
    DEBUG_PRINTLN(eValue);
    uint8_t rainValueHigh = loadState(eValue);
    uint8_t rainValueLow = loadState(eValue + 1);
    unsigned int rainValue = rainValueHigh << 8;
    rainValue |= rainValueLow;
    rainBucket[i] = rainValue;
    //
    DEBUG_PRINT(F("rainBucket[ value: "));
    DEBUG_PRINT(i);
    DEBUG_PRINT(F("] value: "));
    DEBUG_PRINTLN(rainBucket[i]);
  }
}

void transmitRainData(void)
{
  DEBUG_PRINT(F("In transmitRainData. currentHour = "));
  DEBUG_PRINTLN(currentHour);
  int rainUpdateTotal = 0;
  for (int i = currentHour; i >= 0; i--)
  {
    rainUpdateTotal += rainBucket[i];
    DEBUG_PRINT(F("Adding rainBucket["));
    DEBUG_PRINT(i);
    DEBUG_PRINTLN(F("] to rainUpdateTotal."));
  }
  DEBUG_PRINT(F("TX Day 1: rainUpdateTotal = "));
  DEBUG_PRINTLN((float)rainUpdateTotal / 100.0);
  send(msgRainVAR1.set((float)rainUpdateTotal / 100.0, 1)); //Send current day rain totals (resets at midnight)
  wait(DWELL_TIME);
#ifdef USE_DAILY
  rainUpdateTotal = 0;
#endif
  for (int i = currentHour + 24; i > currentHour; i--)
  {
    rainUpdateTotal += rainBucket[i];
    DEBUG_PRINT(F("Adding rainBucket["));
    DEBUG_PRINT(i);
    DEBUG_PRINTLN(F("] to rainUpdateTotal."));
  }
  DEBUG_PRINT(F("TX Day 2: rainUpdateTotal = "));
  DEBUG_PRINTLN((float)rainUpdateTotal / 100.0);
  send(msgRainVAR2.set((float)rainUpdateTotal / 100.0, 1));
  wait(DWELL_TIME);
#ifdef USE_DAILY
  rainUpdateTotal = 0;
#endif
  for (int i = currentHour + 48; i > currentHour + 24; i--)
  {
    rainUpdateTotal += rainBucket[i];
    DEBUG_PRINT(F("Adding rainBucket["));
    DEBUG_PRINT(i);
    DEBUG_PRINTLN(F("] to rainUpdateTotal."));
  }
  DEBUG_PRINT(F("TX Day 3: rainUpdateTotal = "));
  DEBUG_PRINTLN((float)rainUpdateTotal / 100.0);
  send(msgRainVAR3.set((float)rainUpdateTotal / 100.0, 1));
  wait(DWELL_TIME);
#ifdef USE_DAILY
  rainUpdateTotal = 0;
#endif
  for (int i = currentHour + 72; i > currentHour + 48; i--)
  {
    rainUpdateTotal += rainBucket[i];
    DEBUG_PRINT(F("Adding rainBucket["));
    DEBUG_PRINT(i);
    DEBUG_PRINTLN(F("] to rainUpdateTotal."));
  }
  DEBUG_PRINT(F("TX Day 4: rainUpdateTotal = "));
  DEBUG_PRINTLN((float)rainUpdateTotal / 100.0);
  send(msgRainVAR4.set((float)rainUpdateTotal / 100.0, 1));
  wait(DWELL_TIME);
#ifdef USE_DAILY
  rainUpdateTotal = 0;
#endif
  for (int i = currentHour + 96; i > currentHour + 72; i--)
  {
    rainUpdateTotal += rainBucket[i];
    DEBUG_PRINT(F("Adding rainBucket["));
    DEBUG_PRINT(i);
    DEBUG_PRINTLN(F("] to rainUpdateTotal."));
  }
  DEBUG_PRINT(F("TX Day 5: rainUpdateTotal = "));
  DEBUG_PRINTLN((float)rainUpdateTotal / 100.0);
  send(msgRainVAR5.set((float)rainUpdateTotal / 100.0, 1));
  wait(DWELL_TIME);
}

void receive(const MyMessage &message)
{
  if (message.sensor == CHILD_ID_RAIN_LOG)
  {
    // nothing to do here
  }
  else if (message.sensor == CHILD_ID_TRIPPED_INDICATOR)
  {
    if (message.type == V_VAR1)
    {
      rainWindow = atoi(message.data);
      if (rainWindow > 120)
      {
        rainWindow = 120;
      }
      else if (rainWindow < 1)
      {
        rainWindow = 1;
      }
      if (rainWindow != atoi(message.data))   // if I changed the value back inside the boundries, push that number back to Vera
      {
        send(msgTrippedVar1.set(rainWindow));
      }
    }
    else if (message.type == V_VAR2)
    {
      rainSensorThreshold = atoi(message.data);
      if (rainSensorThreshold > 10000)
      {
        rainSensorThreshold = 10000;
      }
      else if (rainSensorThreshold < 1)
      {
        rainSensorThreshold = 1;
      }
      if (rainSensorThreshold != atoi(message.data))  // if I changed the value back inside the boundries, push that number back to Vera
      {
        send(msgTrippedVar2.set(rainSensorThreshold));
      }
    }
  }
}

void prettyFade(void)
{
  float val = (exp(sin(millis() / 2000.0 * PI)) - 0.36787944) * 108.0;
  analogWrite(ledPin, val);
}

void slowFlash(void)
{
  static bool ledState = true;
  static unsigned long pulseStart = millis();
  if (millis() - pulseStart < 100UL)
  {
    digitalWrite(ledPin, !ledState);
    pulseStart = millis();
  }
}

void receiveTime(unsigned long newTime)
{
  DEBUG_PRINTLN(F("Time received..."));
  setTime(newTime);
  char theTime[6];
  sprintf(theTime, "%d:%2d", hour(), minute());
  DEBUG_PRINTLN(theTime);
}

Datasheets

Shopping Guide

100pcs LEDs
LEDs with assorted colors
1715 available - $1.58   Buy
In stock - $1.77   Buy
100pcs electrolytic capacitors
Assorted values. 0.1uF-100uF. Use capacitors to stabilize power to the radio.
941 available - $4.28   Buy
In stock - $2.09   Buy
10pcs 2 Pole Screw Terminal Block
2 pole screw terminal block. 300V 10A
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Stock unknown   Buy
10pcs Female pin header
2.54mm Single Row Straight Female Pin Header strip
1963 available - $1.58   Buy
In stock - $1.40   Buy
10pcs NRF24L01+ 2.4GHz Wireless Transceiver
This is what enables your sensors to communicate wirelessly across a nominal range of 60 meters.
2252 available - $9.99   Buy
In stock - $7.75   Buy
10pcs Prototype PCB
50mmx70mm
4050 available - $3.98   Buy
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1500pcs Assorted Resistors
1 ohm ~ 10M ohm. 1/4W. +-1%. 75 different values.
1014 available - $8.46   Buy
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20pcs 662K 5V-3.3V Step Down Regulator
Inexpensive regulator for adjusting the power to the radio when using 5V Arduino Pro Minis. Warning! Very small and hard to solder.
532 available - $0.99   Buy
Stock unknown   Buy
40pcs Dupont jumper cables Female->Female 20cm
Cables used for connecting radio and sensors.
2560 available - $0.99   Buy
In stock - $0.88   Buy
Arduino Pro Mini Compatible 5V
This is probably the cheapest module. You can connect 5V sensors directly but for powering the radio you'll also have to buy a step-down regulator
1042 available - $2.03   Buy
In stock - $1.70   Buy
BH1750FVI Digital Light intensity Sensor Module
0-65535 lx. I2C interface.
732 available - $2.66   Buy
In stock - $1.19   Buy
DHT22 Module
Humidity range: 0%-100%RH (±2%RH). Temperature range: -40-80°C (±0.5°C).
835 available - $4.50   Buy
In stock - $2.38   Buy
FTDI USB to TTL Serial Adapter
For the Pro Minis you'll need one of these to program the module from a PC or MAC. Handles both 3.3V and 5V!
3569 available - $6.95   Buy
Stock unknown   Buy
Rain Sensor
Tippling Bucket rain sensor hardware. Output pulses when a bucket has been filled.
122 available - $10.52   Buy
In stock - $9.35   Buy

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