PIC Microcontroller

Digital Clock Timer schematic

This clock timer uses a PIC16F628 microcontroller to display 3 and 1/2 digit time and control an external load. The clock includes a calendar with leap year and optional daylight savings adjustments. The timer output can be set from 1 to 59 minutes and manually switched on and off. The clock also has a correction feature that allows an additional second to be added every so many hours to compensate for a slightly slow running oscillator. The oscillator uses a common 32.768 KHz watch crystal and the frequency can be adjusted slightly with the 24pF capacitor on the right side of the crystal...

IR 4 channels remote control with PIC12F629

The circuit above illustrates using the IR receiver module along with a PIC12F629 microcontroller to decode 5 individual IR remote control keys so the circuit will only toggle one of the 4 outputs when a particular key is pressed. The 5th key is assigned to the master clear function that toggles off the 4 outputs. Works with most hand held IR remote controls that send a single data stream. However, some remotes send multiple groups of data and only the first set of 40 bits or less will be recognized. This may result in the circuit responding to more than one key, or a single key may control more than one toggle switch...

Auto-Phone dialer for alarm security system

The circuit consists of a small PIC microcontroller, assembly program, and a few other parts to detect a switch closure from an open door, window, or manual push button and then dial the cell phone number, and transmit a steady tone to indicate the source of the call. The circuit uses the pulse dialing system to interrupt the line connection a number of times to indicate each digit. Pulse dialing (the oldest form of dialing) works by actually disconnecting or "hanging up" the phone line a number of times to indicate each digit. For example, the digit "5" would be dialed by disconnecting and reconnecting the line 5 times in short intervals of about 100mS. ..

PIC Programmer schematic RS232

In the article you will find a description of the universal PIC programmer, which suggested the involvement of Jens Madsen Dyekjar [ http://www.jdm.homepage.dk/newpic.htm ]. Program allows districts PIC12C5XX, 12C67X, 16C55X, 16C61, 16C62X, 16C71, 16C71X, 16C8X, 16F8X, serial EEPROM 24Cxx. It allows to program the microcontroller directly involved (ICSP) and other adapter series programmable components, such as ISO cards. When I needed some time to program the PIC microcontroller, I decided to build a programmer. This solution seemed more operative than I repeatedly asked someone on the programming of their friends...

NiCd/NiMH Battery Charger

Here we use the PIC16711. Rechargeable battery capacity is rated in mAH (milliampere-hours). The total capacity of a battery is defined as "C", that is it can supply C mA for 1 hour, or 2C for 30 minutes etc. Charge rates can vary from trickle charges to keep the battery 'topped up' of 3.3% of C to 5% of C, a slow current charge of 10% of C to 20% of C or a fast charge of 50% of C to 100% of C. Slow charges are not meant to be continually applied, and since NiCd/NiMH batteries are about 66% efficient, they normally last about 8-15 hours. Fast charges such as 100% of C should be terminated after about 1.5 hours, providing the battery is flat to begin with. Once a battery is fully charged, the battery produces gas creating a high internal pressure, and a sudden rise in temperature. ..

Power LED mood Lamp

A good way to mount the circuit board is to use a hot glue gun to "mold" the circuit underneath the lamp housing. There is plenty of space there for your board. At the next photos you can see the circuit board mounted on the small 31cm IKEA Mylonit Lamp. It's clear that current changes as colors are changing. As you can see the max current needed is 232mA. You should keep in mind that this depends on the led you have and the power resistors you choose. As a conclusion a power supply rated at 5V/500mA will be sufficient. The schematic used is shown in the next image. It's as simple as it shows. Take care on the correct transistor mount and correct polarity of power source...

Digital Volt and Amp Meter

The PIC Microchip Processor must be programmed before it will function as a Volt & Amp meter. There are many internet sites and PIC programmers that you can use. I used a Microchip MPLAB ICD 2 during the project. You might need to made changes to the circuit to accommodate a different type of programmer, do read the programmers instructions carefully. The circuit relies on the internal analogue to digital converter (ADC) of the PIC Microchip Processor. The accuracy is dependant on scaling the input voltage for the ADC for all three measurements. The good news is that both the PIC's which can be used for this project have 10-Bit resolution ADC units which should work adequately in most circumstances...

Fish Tank Lights and Temperature Detector

When the tank is cleaned the fish are removed and placed in a small amount of the tank water. The problem is that fish don’t like rapid temperature fluctuations. I guess a simple in tank or stick on thermometer would have done the trick but what is the fun in that? If the unit just did temperature monitoring it would have been such a waste of processor capability, so I thought adding colored lighting would be a great addition. Uses 16 high power LED’s, 4 red, 4 green, 4 white and 4 blue. The tube that the LEDs are mounted in is a section of 3/4 inch PVC conduit. LCD Display to display the mode the unit is in and show the temperature. Liquid sealed temperature to read the water temperature. One button to change between modes. Photocell to turn off the lights when there is adequate room light. This is wired and calibrated but this function has been remove to allow the lights to remain on all the time...

Clock using analogue multimeters ( PIC16F628A )

The Multimeter Clock consists of three multimeters, the first meter displays hours, the second displays minutes and the last displays seconds. A 16F628A PIC microcontroller keeps track of time and outputs a calculated current to each meter to display the current time. The user enters the time by pressing three time adjust buttons. The first button increments the hours, the second button increments the minutes and the third button resets the seconds. Once the time has been entered the microcontroller will keep track of time from there. An interrupt fires every 10th of a second to increment a 10th second counter. Another routine checks to see if we have at least one full second of time, if we do the current time is incremented by a second...

Gear clock using PIC 16f628A

The heart of the clock is a PIC 16f628A microcontroller (PDF). This microcontroller has an internal oscillator however an external 20MHz crystal oscillator is being used since it will have to accurately keep track of time for weeks and months. The microcontroller is interfaced to two buttons and one motor. The interface is very simple, it consists of two buttons. When the left button is pressed the clock advances time using the motor. When the right button is pressed the clock decrements time using the motor. The only issue is when you need to correct time by many hours you would have to keep the button pressed for a long time. ..

The Button Code is a system that allows a single button to act as a keypad. The user enters a 4 digit code into the system using button taps. The button can be placed where the public can access it since like a keypad there are many combinations to keep guessers from activation the system. When the correct code is entered a form-C relay is activated (Normally Open and Normally Closed relay contacts). When activated it can either activate for a programmed time or simply toggle the output whenever the correct code is entered...

PWM Fan Controller schematic

The heart of the PWM Fan Controller is a PIC 12F675 microcontroller. This microcontroller is reading the analog output of a LM35 temperature sensor using a ADC (analog to digital converter) . The resulting digital value is converted to a temperature and a fan is powered proportionally to how hot the sensor is. The sensor is mounted against the hard drive chassis so it is measuring the actual drive temperature and not just the air temperature inside the housing. ..

Talking Yoda head

The talking Yoda head consists of a Yoda mask and a microcontroller system to achieve the desired operation/effect. The basic operation of the project was specified as follows: The head was to be placed inside a closed box. Upon opening the box, the light sensor sends a signal to the microcontroller which, in turn, activates the ISD1000A to play message number one. The audio output is fed back into an A/D converter and processed in the microcontroller to make the mouth mechanics move via servo control. When the box is closed again, message 2 is played. Upon reopening of the box, message 3 is played and then message 4 is continually played until the box is closed again. When the box is closed again, the system resets and prepares to play message 1 again when the box is reopened...

38KHz or 40KHz signal generator

The small 8-pin PIC12C508 is pre-programmed to generate our 38KHz carrier frequency by simply pulsing I/O-pin GP1 (shown above). The PIC will generate either 38KHz or 40KHz, depending on the state of GP3 when power is first applied. If you connect GP3 to ground, then apply power to the circuit, the frequency will be 40KHz. This was implemented for people using the older 40KHz style infrared detector modules. The default is 38KHz with pin #4 (GP3) left floating or (not connected to anything), Pin #7 (GP0) is to inhibit (stop) the carrier output. When GP0 is connected to ground, the PIC will halt generation of the carrier frequency. ..

DMX PC Keyboard Interface

This is the Design for a DMX512 to computer keyboard interface. It sits in line on the computer keyboard and on the DMX 512 chain. Decoding The Lighting data and if one it's set channels is set above 1/2 value this unit will output a sequence of keyboard keys to the connected PC. It is primarily designed to be used with PC connected to video projectors, where the lighting controller may require control of a presentation on the video screen but the PC for the presentation is located in a different location to lighting control. This unit allows a presentation to be controlled form a standard DMX lighting desk. The DMX Keyboard interface has 6 Channels that can be selected to any group of addresses from 1 - 512 in the DMX Universe. ..