It is a very simple data logger project based on PIC12F683 microcontroller. The microcontroller reads temperature values from a temperature sensor on a regular interval basis and stores them into its internal EEPROM memory. The recorded temperatures can be later transferred to a PC through serial interface. I originally published this project on electronics-lab.com last summer. I thought this could be a very good learning project for beginners, and so I am posting it here for Embedded Lab’s readers too.
Tag Archives: PIC12F683
This project describes a motion sensor alarm based on a Passive Infra-Red (PIR) sensor module. There are many vendors that manufacture the PIR sensor modules and almost all of them are pretty much the same in function. They have a single output that goes high (or low, based on specification) when the motion is detected. In this project, a PIC12F635 microcontroller continuously monitors the output from the sensor module and turns a buzzer on when it goes active.
Certain crystalline materials have the property to generate a surface electric charge when exposed to thermal infrared radiation. This phenomenon is known as pyroelectricity. The Passive Infra-Red (PIR) sensor module works on the same principle. The human body radiates heat in the form of infrared radiation which is maximum at about 9.4 um. The presence of human body creates a sudden change in the IR profile of the surrounding that is sensed by the pyroelectric sensor. The PIR sensor module has an instrumentation circuit on board that amplifies this signal to appropriate voltage level to indicate the detection of motion.
This article describes how to play a melody with microcontrollers. A melody consists of notes that must be played with proper timing gap. Every note has a specific frequency. So if you know the notes that you want to play, then first find out the frequencies of those notes. After that, you can program a microcontroller to generate those frequencies at one of its port with proper timing intervals. You can listen the melody on a piezo buzzer connected to the port pin. This project describes the notes and frequencies to play the popular birthday tune.
This one chip data logger uses PIC12F683 microcontroller to read temperature from a DS1820 sensor and store it inside its internal EEPROM memory. The process is repeated in every 1 sec, 1 min, or 10 min interval as selected by user. The stored values can be transferred to a host PC through serial port. The serial communication uses a transistor based TTL to RS232 Level converter circuit to transfer data to PC.
This logger can store up to 254 temperature measurements in its internal EEPROM. Each data is 8-bit and the temperature resolution is 1 degree C. With three tact switch inputs, the user can control Start, Stop, Send, Reset, and Sampling time set operations. The hardware and firmware is available for free.
HD44780 based LCD displays are very popular for embedded projects because they are cheap, easy to interface, can display characters, consume power lot less than seven-segment displays, and most of the present day compilers have in-built library routines for them. However, the only disadvantage is that they require at least 6 I/O pins of microcontroller. Well, you may ask, isn’t that less than what seven-segment displays require? Yes, that’s true but there are circumstances where you don’t have left enough pins for LCD display. For example, if you are going to design a temperature sensor based on a PIC12F683 microcontroller, which has just 6 I/O pins, you won’t have pins for interfacing a LCD. One solution for cases like that is to use serial LCD’s. Serial LCD’s available in the market cost more than double of HD44780 based standard one. The serial LCD’s still have the standard LCD module but it has an extra built-in driver module that receives data/command from a host microcontroller in serial format and convert it to appropriate parallel format suitable for HD44780 driver input.