Control Electronic MIDI Drum

Here’s a design circuit for a MIDI interface between drum pads and computer or hardware sequencer. Using this circuit you can hit pads with drumsticks and store the MIDI data in real time. This is the figure of the circuit;

 

This circuit is based around the PIC16C84 microcontroller which scans the inputs on RB0 to RB7 and when a high is detected the software transmits the equivalent note-on (and then the MIDI note-off after a short delay) for the required drum sound on the MIDI output on RA0.

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Control Uninterruptible Power Supply Using PIC17C43 Microcontroller

That is a design circuit for Microchip Uninterruptible Power Supply (UPS) reference design with PIC17C43 microcontroller. Here’s the figure of the power supply;

At times, power from a wall socket is neither clean nor uninterruptible. Many abnormalities such as blackouts, brownouts, spikes, surges, and noise can occur. Under the best conditions, power interruptions can be an inconvenience. At their worst, they can cause loss of data in computer systems or damage to electronic equipment.

It is the function of an Uninterruptible Power Supply (UPS) to act as a buffer and provide clean, reliable power to vulnerable electronic equipment. The basic concept of a UPS is to store energy during normal operation (through battery charging) and release energy (through DC to AC conversion) during a power failure. UPS systems are traditionally designed using analog components. Today these systems can integrate a microcontroller with AC sine wave generation, offering the many benefits. The PIC17C43 microcontroller handles all the control of the UPS system. The PIC17C43 is unique because it provides a high performance and low cost solution not found in other microcontrollers.

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Control Centigrade and Fahrenheit Scale Digital Thermometer Using LCD Display

This is a design circuit for Digital thermometers are cool devices as they show temperatures in human readable formats. This digital thermometer project is based on a PIC16F688 microcontroller and a DS1820 temperature sensor, and it displays temperature on a character LCD screen in both Celsius and Fahrenheit scales. I selected PIC16F688 for this project because it is cheap (I bought one for $1.50). DS1820 is a 3-pin digital temperature sensor from Dallas semiconductors (now Maxim) which is designed to measure temperatures ranging from -55 to +125 °C in 0.5 °C increments. Here’s the figure of the circuit;

The firmware I have written is able to read and display the entire temperature range of DS1820. In order to test for temperature measurements below 0°C, I put the sensor inside my freezer. While trying this, don’t put the whole unit inside the freezer as LCD display unit may stop working at the freezer temperature. Similarly, bringing a soldering iron tip close to the sensor can do testing for the higher range temperature values.

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Control The Voltage Regulator

The DC voltage produce by this circuit is depend on the load; the heavier the load (more current to the load) means the capacitor discharge time will be more faster and as a result the DC voltage output level will be drop. The circuit above is called unregulated AC to DC converter; because it could not maintain its voltage output level, this kind of power source could not be use in electronic circuit that required constant voltage level in order to operate properly such as in digital and microcontroller circuit. Therefore we need what is called Voltage Regulator Circuit and at the same time works as the DC to DC voltage step down.

 

The first one is the analog voltage regulator, this type of regulator operate the transistor in its linear region (current gainer). The current supplied to the transistor base lead is depend on the voltage different between the reference voltage and output voltage apply to the error amplifier input; for example when the output voltage is greater than the reference voltage, than the error amplifier will make the transistor to conduct less, this mean the voltage drop across the collector and emitter (Vce) will be increase this will make the output voltage to decrease and vice verse. With output voltage being continuously compared to the reference voltage (close loop feedback) by the error amplifier, this kind of circuit could maintain its voltage output level constantly. The disadvantage of using this type of voltage regulator is the power dissipation (power lost as a heat) on the transistor is high especially when we want to use 5 Volt output from 11.33 volt from the unregulated DC source or drain lot of current from it.

The second one is the most efficient voltage regulator as this type of voltage regulator operates the transistor in its saturate region or known as a switching voltage regulator. The working principal is the same as the analog one, but instead of using the constant current to the transistor base lead; this voltage regulator type use pulse current or known as PWM (Pulse Width Modulation) to the transistor base lead and this make the transistor to turn on and off according to the PWM duty cycle supplied by the error amplifier. Therefore by changing the PWM duty cycle we could change the average voltage drop across the collector and emitter (Vce). The inductor (L) is used to release its energy to the load through the diode (D) when the transistor is turn off; and when the transistor is turn on then the transistor will supply the current to the load and the inductor will store the energy in the electromagnetic form; in other word the inductor and diode will ensure that the load will always get a constant current when the transistor is turn off.

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Control DC to DC Step-Up Regulator

This is a design circuit for the Maxim MAX756 is the sample of easy to use DC to DC step-up switching regulator; this chip is used to increase the typically low input DC voltage 1.1 volt - 1.8 volt to the output DC voltage of 3.3 Volt or 5 Volt at maximum 200mA load (300mA on 3.3 Volt output). This is the figure of the circuit;

This means you could easily power your microcontroller project using just a single AA/AAA battery. This kind of step-up power is widely use on digital and microcontroller circuit that powered by low input voltage battery such as micro alkaline 1.5 volt battery. The basic schematic for 5 volt output from 1.5 volt battery. The output voltage of Maxim MAX756 could be selected from 5 volt or 3.3 volt by putting logical low or high on pin 2 (3/5), it also supply the low output indicator detector to the circuit if needed through the pin 4 (LBO). The following picture shows the Maxim MAX756 IC circuit powering the microcontroller’s board using just 1 AA alkaline battery (1.5 Volt).

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Control PIC Frequency Counter Operating Up To 50 MHz

This is a design circuit for general theory of operation of this circuit and notes on frequency counting. This circuit is based on PIC microcontrollers for the main control unit of the circuit. This is the figure of the circuit;

 

The LCD is used in 4 bit mode interface so you only need 4 data lines and three control lines and it then fits into a single 8 bit port.

The crystal oscillator is simply a crystal and two capacitors connected to the PIC oscillator port at OSC1 and OSC2. The capacitors can both be fixed at the same value unless you want to tune it using a frequency reference. If you don't have an accurate reference then use fixed capacitors. The PIC micro can be any type that has a Timer 1 hardware and and has enough memory to hold the program. The LED is toggled at the end of every gate time to indicate that the processor is alive - so if there is no input signal you can tell that the software is working.

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Control Multiple PIC16F84 Proteus Simulated Projects

Proteus is a software tool that allows simulation of various circuits including microcontroller based ones. You can complete entire project with simulator including hardware and software parts. And only then you can move towards manufacturing real device. This page is dedicated only to PIC16F84 microcontroller projects where you can download ready to simulate about 31 complete project. 

 

Projects include implementation of popular interfaces like LCD, Timers, EEPROM writing, Interrupts, I2C and 1-wire communication, motor control and so on. Each project include Proteus project file and microcontroller hex file that has to be attached to model to start simulate.

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Control MIC 702 Mictronics Circuit

This is a design circuit that can be used to convert a standard LCD interface parallel to serial interface model, use a microcontroller or a dedicated circuit such as the MIC 702 Mictronics you can download the complete data sheet and French by clicking this link. This is a circuit specially designed to transform the parallel interface and LCD display logic integrated asynchronous serial interface standard. This is the figure of the circuit;

 

The MIC 702 is connected directly to the display with which it is perfectly compatible. Notice the connection with only 4 data bits of high weight since the MIC 702 operates in the display mode twice 4 bits. PC side, the connection with the serial output of the PC does not involve any level converter for RS 232 TTL, this role being played by the only resistor R1 22 ohm whose presence is essential. BAUD The tab allows you to choose the operating speed of the circuit between two speeds: 9600 bps up with S1 or S2 with 2400 baud up. The leg POL allows the circuit to interpret the serial data as direct or inverted. As it is in direct RS232 link should be link this foot to ground to indicate the MIC 702 that receives data reversed. Linkage to +5 volts it would receive direct evidence as would be the case if we wanted to use this circuit with a Basic Stamp example.

Subject to use a display not backlit, the total consumption of the circuit is low enough that it can take its power directly from the output control signals to the RS 232. It is the role of diodes D2 and D3 associated with IC1, which is a regulator with low dropout voltage and low consumption. If you insist on using a backlit display, it is possible that consumption of its single backlight exceeds the possibilities of the PC's serial port. You can use an external power supply via the diode D1. A voltage of 9 volts at a flow rate of a hundred mA appropriate.

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Control Driver an RGB LED Using Three Microcontroller Pins

The RGB LED contains three LEDs encased in one shell: Red, Green and Blue (some contain an extra blue led - as blue LEDs generate less output intensity (candela) per mA). It looks like a single white led except that it has four leads - one for the common ground connection and one for each led. This is the figure of the circuit;

This project uses puls width modulation to drive each of the leds in the RGB led. By changing the duty cycle of each PWM signal you can control the average current flowing through each led creating any color you want. The limit is set by the resoelution of the PWM (set at 256 steps per channel). The project relies on persistence of vision to make it appear that the led is continuously driven (the PWM signals must be repeated quickly enough so that you do not see any flicker) at a rate greater than 50Hz (approx). Too slow and you begin to see the led flickering.

By varying the current through each led you can create almost any other color but at close range you only see the individual colors of each LED. To see the 'merged' color view it from a distance or put a diffuser over it. I used a small piece of baking paper - which is transparent enough to let the light through and opaque enough to diffuse the light from the three LEDs. In a proper design you would use a semi-transparent plastic.

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