Are you too lazy to feed your pet? We love our pets, but sometimes we also hope to let the pets to automate this. Today we will use Arduino UNO to do an intelligent automatic pet feeding! The main components of the project include an RTC module for tracking time, managing feeding plans, one to monitor food level distance sensors, one is used to distinguish daytime black night Photosensitive sensor, one RFID used to identify pets. All right! let's start!
hardware
Arduino Uno
Temt6000 photosensor
GP2Y0A21YK Sharp Distance Sensor
RFID MFRC522
buzzer
SG90 motor
RTC DS1307
software
Arduino IDE
tool
Bottle (or any food container)
Metal plate 35 × 25 cm
Step 1: Connect the photosensitive sensor
We use SparkFun photosensitive sensor TEMT6000 to test during day and night. The reason is to distinguish between these two, the main reason is because we have to make sure when we need to put food, it takes more time to get intervals between food devices. Temt6000 photosensitive sensors have 3 pins: SIG, GND, VCC. The steps of receiving this sensor on the Arduino board are very simple: VCC is connected to 5V pin; GND pin on the board, then SIG needs to be connected to analog input. I chose A0 pins. The action of the output pin SIG seems to be a transistor, so the brighter the light near the sensor, the higher the voltage output from the pin.
The figure below shows the relationship between the current and illuminance perceived by the TEMT6000. Illuminance is a total optical flux (that is, the visible light emitted by the light source, in an LM unit) divided by the area (m2). In general, 1 illuminance (IX) = 1 / m2. The TEMT6000 can identify typical human visible light spectroscopy and wavelengths between 390-700 nm.
Since the sensor is connected to the analog pin, the resolution of the modulus converter is 10 bits, so its maximum is 1023. For example, when the sensor receives the brightened irradiation from my mobile flash, the value read from the sensor is approximately 1023.
Photosensitive sensor code:
Step 2: Add a distance sensor
To measure distance, I chose an analog sensor (Sharp GP2Y0A21YK) because it is best better than other distance sensors. The working principle is as follows: First, a signal is issued, and when it discovers an obstacle on the road, it will also send back a signal (a voltage value, the voltage value varies from the disturbance of the obstacle), which is converted into distance.
GP2Y0A21YK will be placed above the food container. Before opening the automatic feeding function, you need to measure the remaining space in the bottle (that is, how much food is available). With this distance sensor, the system will detect the food container (or bottle) or empty. The specific work mode is as follows:
Smaller distance: Automatic system will only increase a small part of food;
Medium distance: Your pet will get half of food;
The distance is large: the automatic system will feed all the food.
The distance here represents the distance from the position of the mounting distance sensor to the bottom of the food container. Since the sensor ranges from 10-80 cm, the sensor needs to read the correct distance value above 10 cm above the top of the food container.
How to determine the best fit lines of the sensor:
The relationship between the output voltage of the sensor and the countdown of the measurement distance is approximately linear in the available range of the sensor. You can use this figure to convert the sensor output voltage to an approximate distance, and the method is to create an optimum fitted line, link the counting of the output voltage (V) to the distance (cm). The simple form of a linear equation may illustrate the distance to the reflective object is about equal to a constant scale factor (~ 27V * cm) divided by the value after the output voltage of the sensor. Therefore, an constant distance offset is added and modified the scaling factor to improve the fitting of this line.
Based on the "typical value" of Sharp, the sensor value is converted to a distance (the formula is only applied to the sensor value between 80 - 500):
Distance (cm) = 4800 / (Sensor value - 20)
This sensor can find the distance from the object, which exhibits a very narrow edge, such as a very sharp wall.
Note: The output of the sensor varies from unit to depend on the characteristics of the target (reflectivity, size, motion direction, target alignment).
Code:
Step 3: Determine the time
The RTC DS1307 model will be used to determine the time. A real-time clock system assumes the function of determining the time. This circuit is based on a crystal oscillator having a frequency of 32.768 kHz. The principle is similar to the watch. A crystal vibration-based mechanical resonator can produce an accurate frequency. This frequency is used to track the date and time from the computer.
This is a utility module, even when the system is turned off, the battery provided above can guarantee the continuity of the system.
In order to achieve the best use, you need to add two libraries to the module.
DS1307RTC
time
Connection line (this library is already included in Arduino IDE, so it is easy to add it)
We will run a test code to detect the module. When we upload the program to the Arduino Board, the serial port monitor displays the current date and time. These two libraries have an example code for finding the date and time, called "Settime".
Find the setting time:
Click Arduino IDE → File → Sample → DS1307RTC → Setting time
In the figure below, you will see that the module works normally when the current date and time are displayed.
Here, we will only measure hours of operation. To do this, we need to extract the exact time from the RTC module. This will be done by the RTC simple function named "SetSyncProvider (RTC.get)". After this feature is implemented, you will be able to see the number of hours on the serial port monitor and the value on the distance sensor and the photosensor.
Code:
Our other product:
