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AC to DC & DC to DC
Solar Cell Circuits
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Light Laser LED
Digital to Analog
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Data Bus Circuits
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Current to Voltage
Frequency to Voltage
RF Converter Circuits
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voltage to frequency
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8051 / 8052
PCB CAD Software
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Remote Control Toy
H Bridge Circuit
Interconnection & Timing
Digital Signal Integrity
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4 Band Resistor
5 Band resistor
6 Band resistor
PIC Microcontroller Circuits
PIC Microcontroller Circuits
3-Wire Serial LCD using PIC12F683
The character data and command from the microcontroller is transferred serially to a shift register (74HC595), and the parallel output from the shift register is fed to LCD pins. 74HC595 is a high-speed 8-bit serial in, serial or parallel-out shift register with a storage register and 3-state outputs. The shift register and storage registers...
PIC16F84A Gas Detector
This is a gas detecting circuit capable of sensing many different types of gases. The sensor used is the GH-312 and from the datasheet it is capable of sensing gases like smoke, liquefied gas, butane and propane, Methane, alcohol, hydrogen, etc. I've used a 9V battery for this project because the sensor requires a 9V input. The output when the...
Flood Sensor with 12F683
The water detection time is less than 10 seconds. Since the microcontroller enters a low consumption state between readings to preserve battery life, this state is always 10 seconds long. If water reaches the probes while being in the low power state it will have to wait until it finishes the sleep state before it can trigger the alarm. Also,...
Security Alarm System (PIC16F877A)
This system uses a Microchip's PIC16F877A as a main controller, LM339 as sensor interface, UM3561 as a tone generator and ?PC2002 as a speaker driver (audio amplifier). LM7805, LM7812 and LM317 voltage regulators are used to obtain +5V, +12V and +3V respectively. Touch tone phone dialing interface. 5W High powerful audio alarm. 2 sensor...
PWM fan controller with PIC 12F675
The temperature sensor U2 needs to be located next to the item being monitored. As the temperature increases the motor duty cycle will increase. D1 and R2 are optical components, they only need to be installed for a visual indication of the current duty cycle. Q1 is a 2N4001 NPN transistor. Resistors are all 1/4 Watt. D1 is a blue LED.
DTMF Phone Dialer with PIC16F690 and NTE1690
The circuit uses a NTE1690 DTMF dialer chip and a PIC16F690 microcontroller. Because this is an IP phone and I cannot just send the DTMF tones over the line, the easiest place to plug in the box is between the phone and the handset. The box has two RJ9 ports at the back - one gets connected to the headset's port on the phone, the other to the...
PIC16F877A Astro Clock
It has 16 timers that can be independently paused and restarted, and can run forward or backward. There are 16 alarms with configurable sounds and actions. Timers can show Earth, Mars, Jupiter, etc. times at the same time. How about sidereal time, Moon phase, Jupiter's Great Red Spot transit time, and anything periodic in general? Simultaneous...
Scientific Calculator Watch
The uWatch comes as a kit of parts. All of the electronic SMD parts on the PCB are pre-assembled. The uWatch is normally in sleep mode and powers down the LCD to save battery power. (approx 3mA LCD on, and 15uA LCD off) To switch the uWatch on press either the MODE key or the RCL/STO key. The uWatch has three "modes": 1) Time/Date display. 2)...
PIC hydro system controller
The ELC presented here has some flexibility, thanks to being software-controlled, but also has its limitations: It's intended for microhydro systems that employ a single-phase synchronous alternator, working at 220-240V, 50Hz, in a power range up to 25 kilowatts, and using up to eight dump loads, some or all of which can be "useful" loads, such...
Spider robot with PIC16F84
To get enough outputs from the PIC chip, a pair of 74HC164 shift registers was used. These need only two lines from the PIC (data & shift) to produce the twelve signal pulses for the servos. A single bit is shifted into the first shift register, then, after a specific delay, it is shifted to the next servo. The second shift register cascades...
Backup Power System with PIC16F870
The PIC16F870 keeps track of battery voltage as well as both charging and discharging currents. It also drives the 4 digit display, and switches the AC and load relays. The basic operation is as follows: While AC power is available, the battery voltage is constantly monitored and topped off as needed. When the AC power fails, the load relay...
Microcontrolled Lab Power Supply
This unit delivers 0 to 20 volts at up to 4 amps in 0.1 volt increments. The entire device runs on a PIC16F870 (about $3 in small quantities). This is basically a switching power supply with the voltage regulation done in software. The PIC used here has analog inputs (used to measure voltage and current) and hardware PWM (pulse width...
5W Chinese PLL FM Transmitter With LCD Printed Circuit Board (PCB)
Here's PLL FM transmitter circuit from china. This circuit uses the familiar 2SC1971 for final power amplifier stage. The PLL controller of the FM transmitter use SAA1057 and PIC16F628 (download HEX file).
Dual DC motor speed control
Here is a design for a DC motor speed control featuring: Efficient PWM H-bridge MOSFET architecture. Supply (battery) voltage range from 4.2 to 13 volts. High current capacity for driving large motors (65 amps max). Input compatible with standard RC hobby receivers. Individual control of 2 motors. Mixing of steering and throttle into "tank like"...
PIC16F627A Touchpad circuit
This board layout was created using the SOIC version of a PIC16F627A without drawing the usual schematic first. Most of the part values are etched on the Layout. The SIP resistor packs I used are 10k ohm, some experimentation with this value may be useful. Three pins are provided for 5 volts, ground, and TTL serial output on a standard...
Line Powered Phone Messager (PIC16C819)
The phone company provides 3 levels of power. With no devices 'off hook' the line rests at 48 volts DC. If you draw any more than a fraction of a milliamp or so, you get the phone company's attention and a dial tone. When the line rings, you get about 100 volts (rms) of AC signal on top of the 48 volts DC for 2 seconds on and 4 seconds off. The...
Phone Call answering machine (PIC16F870)
The PIC16F870 chosen for this project has seval analog channels. One of these is used to capture the DTMF tones and decode the digits. The actual phone connections are made using a 'hacked' 5 line expandor from Radio Shack. This device connects between the phone line, an answering machine, and your phones. When a phone call comes in, the...
3.6 Volt Lithium Ion Battery Charger (PIC12F675)
Lithium Ion batteries pack a lot of power by weight compared to other types. There are 2 things that need to be handled differently than nicad on NiMH. They cannot be used as a direct substitute (even if they look like other AA's) since they run at about 3.6 (or so) volts. They cannot be charged in the same way as nicad or NiMH.
This programmer requires only a basic terminal program capable of uploading an ascii PIC HEX file. It does not matter what operating system or computer (MAC, Win98, XP, Vista, DOS, Linux, etc.) is used to talk to it. All of the software necessary for programming is in the unit's own PIC (16F628) which incorporates a set of programming algorithms...
This device is built around a PIC12F675 (a dandy little part from Microchip). The number of cells (1 to 8) is programmed in using the one button. The cell count is saved in EEPROM the next time you power up the device. Using just one button for all operations is a bit tricky, but easy once you try it a few times. There are 2 types of button...
Incect Robot circuit (PIC16F818)
Very little extra circuitry is needed to do both forword and backword walking sequences along with a few other tricks. The PIC16F818 has a lot of features that work well in this situation. As you can see from the Schematic and Source Listing, position pulses for the 2 servos are generated dirctly from the PIC. Also, the room light level,...
InfraRed Detector (PIC12F629)
This unit uses one TSAL6100 IR/LED emitter from Digi-Key. This IR diode has a narrow (10 degree) radiation pattern at 940 NM. It is driven via 2n2904 transistor for maximum current pulses. The detector is a Vishay TSOP4838 38Khz integrated receiver module. The 38Khz signal for the emitter is generated in software. Here is the idea: Send out a...
Frequency Locked Loop for HF
The principle of operation is quite simple, a counter measures the VFO frequency, the new reading is compared with the previously stored value and an adequate correction is applied consequently. This process has been implemented in the past using several discrete TTL logics, now a single microprocessor can do the job much better, moreover...
Programmable frequency meter
The basic idea comes from the AN592 Microchip application note: "Frequency counter using PIC16C5x". where you may find a simple software wich implements a frequency counter using a PIC microcontroller.I wrote a specifically designed software to improve the counter resolution, to handle the IF mode and value by means of an operating menu, to...
1 GHz Frequency Counter
This very simple counter can be used to measure the frequency of various wireless devices. Applies in reviving the transmitter and its operation as a control monitor frequency. It can be used as a scale to the receiver. Due to the simplicity of the counter should not miss any of the equipment bastlí?e that similar facilities are still owned....
Digital Encoder with PIC16F57
This encoder can transmit the state of up to 16 TTL digital inputs using an RF or infrared transmitter. When enabled, the included modulator automatically generates the 38kHz IR carrier. Containing a PIC microcontroller, the circuit is very flexible. You can decide which transmitter inputs will trigger a transmission. You can control the...
Digital LCD thermometer ( PIC16F871 )
The circuit drives the LCD pins with 50% square waves. Each segment on this LCD is connected to the COM backplane and a separate pin. When a pin is driven in phase with the COM pin, the corresponding LCD segment gets zero voltage, and is off. When a pin is driven in reverse of the COM pin, the corresponding segment gets an alternating voltage,...
Light timer switch with PIC12F629
This is a lamp timer capable of operating two separate relay switches. Outputs can be in three (or restricted to two) states: OFF, delayed ON and constant ON. Delayed ON mode is indicated by the LEDs. The source code is easily customizable for your needs: set your desired delay time or disable constant ON state. press the button once to turn on...
Greenhouse irrigation controller ( PIC16F84 )
This is a simple one-valve irrigation controller made for our greenhouse. The code contains a software real-time clock (RTC) and a multiplexed 8-digit LED display and keyboard you can use in other projects. The operating software is simple, it contains a real-time clock and a day counter. The valve is turned on in regular intervals in the same...
serial LCD interface for PIC
If you are developing applications for the PIC mcu, and miss debugging tools, or don't have enough I/O pins for a parallel LCD interface in your design, this serial interface can help printing debug messages and/or reduce the pin count. This version uses a Hitachi HD44780 compatible LCD module in 4-bit mode.
Water Level control and monitor with PIC12F675
I found some similar circuits but aren't good enough for me. Some circuits measure the water's resistance to determine the level. That is dangerous for drinking water (contamination) or explosive liquids because electricity is in contact with water. The Pressure sensor have a tube. The tube end on the botton of the tank. When the liquid fill the...
PIC16F628 as digital Tachometer
Pin 3 defines the Display type: Common Cathode or Common Anode. Connect this pin to GROUND if you are using common cathode 7-segment led displays. To use common anode displays, connect it to VCC (positive) Pin 4 is the signal input, you can use optical sensors (Fototransistors, fotoresistors, etc), magnetic sensors (Hall effect, reed switch,...
Arduino Projects and Circuits
AVR Microcontroller Circuits
Microcontroller Programmer Circuits
68HC11 Microcontroller Circuits
8051 / 8052 Microcontroller Circuits
255W Valve RF Transmitter circuit
This transmitter of 255W is depended on the coils we put at it to work in both the middle and the short waves. The power in the antenna is 255W and includes 4 states. The first consists of the EF80 that works as a COLLPITS CLAPP oscillator. Frequency selection is done in a somewhat unusual way: Instead of the variable capacitor, it uses a...
Arduino DAC Signal Generator project
Once the circuit gets current, all variables are initialized and the loop function is continually running. Initially all LEDs are off and there is no signal at the output. By pressing the signal switch, the first light that shows the most signal is at the output and the D0-D7 terminals give the appropriate signal which, when passing from the...
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...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial
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In-Circuit Debugger (ICD) with unparalleled speed and flexibility
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Microchip's fourth-generation in-circuit debugger
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Sign of the times: "Free microchip implants in lobby today!"
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