Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
Metal Detector Circuits
Liquid Sensing Circuits
Light Sensing Circuits
Voltage Detector Circuits
Air-Gas Detection Circuits
Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
Free Energy Circuits
AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
Analog to Digital
Data Bus Circuits
Voltage to Pulse
Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
Voltage to Current
voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
Interconnection & Timing
Digital Signal Integrity
Transmitters & Receivers
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
PIC Microcontroller Circuits
PIC Microcontroller Circuits
Sound amplitude meter
I made this project as a test to improve a technic to read analog values without analog-to-digital converter. (ADC) I ended with this "sound meter". It may not work perfectly, it needs some improvement but works anyway. It have the feature of "auto-calibration", so it detects the signal, amplify it and measures it. Because the "auto-calibration"...
Security Lock with keypad and LCD (PIC16F84A)
Finally I was able to control an LCD Hitachi display and a 12-key matrix keypad with only one 16F84 or 16F628. In a near future, I will be able to control a full QUERTY-type keyboard and a LCD display. The biggest improvement on this projects was the compatibility with the Microchip PIC 16F84 and the 16F628, also the 16x1 or the 8x1 LCD Hitachi...
ON/OFF button using Microcontrollers
Using a switch to power up your microcontroller projects may not be a good idea if you need to "wake" the PIC during some events. For example: A metal detector sends a pulse indicating a car is ready to enter into a garaje, so the user needs to type a password to open the garage door or just slide the access card. You may leave the...
Led Clock using PIC16F84
Using only 2 capacitors, 3 resistors, 4 seven-segment Display, 1 xtal, 2 switches n.o. and 1 Microcontroller PIC, you can build this Digital Led Clock. you can use common anode or common cathode display, just select the display type. Here is the pinout information: Pin 3 defines the display type. If you will use common cathode display, connect...
LCD digital Clock using PIC16F628
The reason why I'm using a LCD display is because it allow me to display many characters and it doesn't need to be "refreshed" as 7-segment Led displays. Also, the interface requieres less I/O pins. For this project I used a 16x1 LCD Display with 4-bits interface.
Rotating Message board using PIC12F629
A simple rotating display. Just spin and enjoy. While the "Air display" is rotating, it writes the message on the air. Because the "persistence of the vision", you will be able to read the message. The operation is super simple and you don't need an user manual. Press the button to turn it on. Press the button to change the message and press the...
Video Switcher with PIC16F819
This device uses the second method (which, if you don't already know, requires about 100 times less parts), but adds motion detection to switch cameras. The usual way to detect motion is to store a complete video frame and then look for changes on successive frames. Again, a lot of trouble can be saved by only sampling 64 locations on the...
PIC16F84 Solar Charger
The previous version of this device used pulse width modulation (pwm) to control the power from the five solar panels to charge the battery bank. Under full sun conditions the MOSFETS got a bit warm and the whole unit radiated a lot of RFI. This design uses a set of relays - one for each panel. If the controller decides the battery voltage is...
Remote IR controller
This unit provide 2 way IR communications using a numeric keypad and an LCD display. Data is sent and recieved in ASCII with no regard to what the data means to any particular device. The ASCII data still needs some form of encoding. For this I chose 10-pulse coding of 38Khz IR using a nifty 99 cent receiver chip , TSOP4838 The transmitting is...
Phone digital answering machine
This unit is an upgrade of the previous phone call interceptor. Instead of using an answering machine to provide the outgoing message and recording functions, it uses the ISD4004 (from Windbond Electronics). The ISD4004 records up to 8 minutes of audio. I use the first several seconds for outgoing message prompts. The remaining time is used to...
Color organ with PIC16F84
Flash-back to the 60's with this 5 channel unit with up to 100 watts per channel. This unit uses a PIC16F84 with an 8 bit A/D. The signal from both stereo channels is combined and digitized. Each of 5 frequency bands is processed using a 16 point FFT. Then the level of each channel is output as PWM (pulse width modulation) to a set of solid...
Capacitor discharge ignition system ( PIC 16F615 )
This device uses a PIC12F615 to implement a capacitor discharge ignition system. When the switch (button) is closed, the PIC sends pulses to the IRF644 MosFet creating high voltage pulses to charge the 1.0 uf/250 volt capacitor. The voltage is read back via a 1M/10k divider until 200 volts is reached. Then the SCR (mislabeled triac above) is...
Signal Generator 20KHz
This fucntion gernerator IC is specified to work to 20 MHz. So far, this unit works nicely to 50KHz. Since I seldom need signals higher than that, it has taken up a happy home on my workbench and further development is iffy at best. There are two basic approaches to controlling the frequency in this type of device. One way is to adjust the...
Phone Line Simulator with PIC16F819
Creating projects that connect to the phone line can be a real chore without some device like this. It generates the 48 volts DC for the on-hook condition, the 100 volts AC for the ring signal, and the 20 milliamperes DC for the off-hook condition. To use the device, a phone is connected to the left jack. When it is picked up (off-hook), a ring...
PC interfaced Security System
Creating a modular, networked, home control system was greatly simplified by using common 4-wire phone cable with stake-on connectors. The cable feeds both power and network signals to the various modules. Each module is made on a single sided circuit board with RJ-11 connectors (for the network / power) along with other connectors as needed....
Fan Controller with PIC12F675
This device acts as a variable speed control for the heater blower in a car. It takes its power directly from the existing wiring and connects with just 2 wires. It will also work for any 12 volt device up to 10 amps. A PIC12F675 provides all of the necessary functions. It reads the (10k) linear potentiometer and generates appropriately timed...
Furby robot using PIC16F819
There are several websites documenting the original Furby circuit board. I decided to replace the original circuit entirely and replace it with a PIC based controller. The mechanism of the Furby itself was designed around micro- controllers. It has one motor that runs the eyes, mouth, and ears in sequence. Two sensors are provided from the...
A Talking Fish using PIC16F819
These items were sold nationally several years ago. The fish would sing, open its mouth, turn its head, and flap its tail. After removing the back panel, all of the existing electronics were removed leaving only the 3 servo motors, speaker and photocell. The reworked insides are shown here. Wires from each of the motors and from the photocell...
Talking Frog Box using PIC16F870
This device 'listens' to a conversations and then interjects words and phrases at inappropriate times. I got this box at a local thrift store for $1.50 (special, this week only). It has a nice hinged top and a place to insert a panel with a designed glued to it. Ok, so I found this frog on the net and dug up the Egyption boarder from somewhere...
Video title generator
Want to add video to your next project? This device uses a PIC16F819 and not much else. Getting 20 characters to a line is possible by using the SPI port to generate video. Neat trick, eh? The character set is limited to upper case and a few punctuation marks and uses a 'folded data table' to store the image data in the space available. Input to...
Magnetic Card Reader with PIC12F675
The reader mechanism shown was purchased from All Electronics for $1.50. The unit provides the magnetic head on a spring mechanism along with low level head signal amplifiers and data slicers. Three signal lines comming from the unit provide card presence, clock, and data. When actively reading a card, it draws about 50ma of current at 5 volts.
Car Controller using PIC16F870
Our present car controller runs on a single PIC16F870 micro and provides functions for remote door locks, headlight reminder, and car finder. It is constructed using wire-wrap to allow for future expansion and is mounted using Velcro on the passenger side of the center console. The downside of this design is that changes to the system require a...
autodetects baud rate circuit MAX202 and PIC16C54
The popularity and easy access of RS-232 ports lend them to many communication projects. You can use a port as is” or as a tiny parallel port when the exchange uses only control lines. Before the asynchronous serial-data transfer between two devices can take place, you must ensure that both devices are configured to the same data format and...
LED SignBoard with PIC 16F84A
The pins RA3 to RA0, are used as outputs driving each column LED. The pins RB0 to RB7 are used as outputs driving signal for each column LED. The 74HC154 (Decoder 4 to 16) is the chip that decodes the signal into a binary digit dekaexapsifio. In the left figure all the pins of the door at a reasonable RA 0 (Low), in which case only the output 0...
8 LED Effects using PIC16F84A
Five pins RA0 to RA4 are used as inputs. The pins are connected to the 5V average resistance 10K (Pull-up). So when no switch is not depressed all the pins have a high potential (HI +5 V). When one of them is pressed then the foot is connected to get a low potential (LOW 0V). When a switch is pressed, then the phenomenon of 'Bounce' (Debaunce),...
Count Down Timer with PIC16F84A
The choice of material to read or drive is the definition of three digits (Bit), RA0, 1,2 PORTA of the PIC at the entrance of 74HC138A. To select a material for reading or driving an output of 78HC138 is '0 '(Low), forcing the transistor (2SA1015) to conduct and thus is the material with the feet of PORTB. This function ensures that there will...
The SCHAER+ programmer is a programmer for PIC18 family from a PC parallel port (LPT). It is derivated from the SCHAER programmer I used to download my projects in PIC1684. The SCHAER+ programmer should be improved to use a USB connection, without any external power supply... The SCHAER programmer I'm currently using allows me to program chips...
A/D converter 16Bit with LCD and PIC18F2550
The analog to digital converter (ADC) is a commonly required in most of the projects. Analog voltage measurement can be done using the ADC hardware built in together in a PIC. The picture below show a simple setup for measuring the voltage through the adjustment of the potentiometer. PIC used in this example come with a 10 bit ADC. In the...
Auto Baud Rate with PIC18F2455
Most of the newer PIC come with the EUSART module which have the function for auto baud rate detection. The features allow a person to set the baud rate at runtime by sending the character "U" or 0x55 to the PIC. With ABDEN (auto baud rate enable) bit set and using BRG clock as a reference, each rising edge occurring on the RX pin is taken as a...
PWM controller with PIC18f2455
The use of pulse width modulation (PWM) is common for the use of controlling power to a particular electrical device. Motor speed control, LED contrast control, power supplies are some of the example usage of PWM. 18 series PIC always come with a CCP module which is capable of generating PWM. The picture below shows an example of using the...
Timer and Interrupt
There are 4 timers in PIC18 which are timer0 to timer3. Timers are used when precise timing event need to be generated. Timers are usually used in conjunction with interrupt to keep the timing accurate. This guide will show an example of using timer0 to count a timer for every second. The circuit used for this example is the same as the circuit...
Programmable Sound Generator
The AY-3-8910/8912 is a register oriented Programmable Sound Generator (PSG). Communication between the processor and the PSG is based on the concept of memory-mapped I/O. Control commands are issued to the PSG by writing to 16 memory-mapped registers. Each of the 16 registers within the PSG is also readable so that the microprocessor can...
Arduino Projects and Circuits
AVR Microcontroller Circuits
Microcontroller Programmer Circuits
68HC11 Microcontroller Circuits
8051 / 8052 Microcontroller Circuits
Recording circuit of phone conversations using PC
This circuit is used to record telephone conversations on your landline telephone. All you will need is this small circuit and subscription of your PC. There are few times when we forget what we said or told us. So we need recording. Sometime, not many years ago, recording of this kind of conversation was done with a small tape recorder. The...
FM Micro-Transmitter Bug Surveillance Circuit
The transmitter we recommend to build is quite simple. It can even be built by a beginner. However, unlike the ease of construction and its small size, it is almost certain that it will impress you with its outstanding performance. Its autonomy is 12-15 hours, with a 9 volt battery and its range is from 100 to 300 meters depending on the...
Construction of 50Watt 8Ω two-way Hi-Fi Speakers
The presented speakers are distinguished for their small dimensions and their extraordinary sound. Our home space is often limited and prohibitive for large speakers. This limitation does not mean that we will stay without high Sound Quality. Its design is simple, low cost and is easy to construct. Speaker types are too many and are designed in...
GSM modem circuit with Wavecom WMOi3
Modems are devices that connect either remote devices to a computer, or two or more computers to each other. Their connection is usually wired. The GSM modem we present is wireless. It can connect two computers, a computer with the internet or even be the central unit for a data acquisition system. Generally the construction is a GSM phone...
1W UHF Linear Amplifier with BLW33
This circuit is an amplifier for small transmitters operating in the UHF band, specifically in the 450-800MHz range. The amplifier works in class A and we used the well-known Philips BLW33 transistor for its manufacture. The construction, although simple, can be said to be quite critical due to the high frequency singularity. To achieve this, a...
8W Amplifier with TDA2003 circuit
Many times a small amplifier is needed to meet the needs of small spaces. This amplifier can be either mono or stereo, with this circuitry you can comfortably drive two small speakers. To build the amplifier you do not need anything but a few materials and a small power supply. The power of the amplifier, although low power, will solve many...
FM Linear Amplifier 400mW
This amplifier is intended for amplifying low signals from oscillators in the FM band. It does not have frequency regulators with variable capacitors and coils, it has a wide range and moderate power capable of driving several linear amplifiers. The whole construction is based on the two low-power 2N4427 transistors, which are designed for the...
50 Watt Hi-Fi power amplifier circuit
SGS Thomson's integrated TDA7294 is a high-frequency acoustic power amplifier, with true high-precision specifications, suited for all relevant applications. Its main feature is much higher output power than is usual in amplifiers with similar distortion performance. According to its manufacturer, the output stage of this 15-pin integrated can...
RF Remote Control Switch Rx-Tx circuits
This circuit consists of a 2048 radio remote control transmitter and the corresponding wireless receiver with very high reception sensitivity and low consumption. The combination of the two above gives a high-reliability remote control, ideal for security systems, alarms, automation, etc. At home, in the car and elsewhere. Using the wireless...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial
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