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SCR bridge control – I am using a PIC18F4520 to control an SCR bridge. I am getting correct firing pulses but Proteus on my PC can’t simulate 4 SCRs at the same time. It gives me a GMIN stepping error. I am attaching my circuit in PDF format. I am also attaching Proteus Simulation and a document which I referred to make the circuit. Can anybody tell if my circuit is correct and will it work in hardware? Read more

Differents tasks with one-button push – Can somebody tell me how to perform two different tasks with one push button; i.e, if the push button is pressed once, it performs task A. If the button if pressed the 2nd time, it should perform task B and it should wait till the button is pressed again. I am using 89c2051 and Assembly language. Read more

SIM808 (ATE0) echo problem –  I have been trying to interface SIM808 with PIC18f4580.I tried to debug the code using a PICkit3 debugger. I sent (ATE0) command to turn OFF echo mode after sending (AT) command. I am using an LCD to display the response from SIM808. The problem is that whatever I sent is coming back i.e., ECHO mode is not turning OFF. Read more

Arduino UNO unsure about coding –  I am doing a project of current measurement using the LEM LA 55-P transducer which senses the strength of magnetic field produced by a current-carrying conductor traveling through the hole of the sensor and outputs to a linear milliamp output. I want to interface this sensor with an Arduino UNO but am not too certain about the code required. Read more

PIC programming, MikroC pro, uploading code – I have been using the PIC18f45k22 microcontroller. I created a hex file in MikroC Pro. Then I loaded it to Proteus and it’s working fine. Next, I wanted to load it into a real PIC. I am using PICkit3 and MPLAB IDE V7.76. I connected the pins from 1 till 6 to MCLR, Vdd, Vss, PGD, PGC and left the 6th pin not connected as PIC18f45k22 doesn’t have a PGM pin. Maybe the problem is with MikroC pro? Read more

Firmware update over the air – I want to update firmware for PIC32MX230F064D over the air through SIM808 module. How? Read more

16×2 LCD-PIC Display only black squares showing – My code was working fine but suddenly all the character are in a black square box. I changed to new LCD 16×2 display & PIC16f877a controller, development board but the same problem happens. Read more

Controlling a washing machine –  I am designing a new control circuit for my washing machine. It is an LG WF-650 automatic washing machine. What I can’t understand is how to switch from WASH to SPIN. There are no electrical means to switch. The motor agitates when the capacitor is switched from one phase to other. But how do I perform the spinning? Read more

How to control voltage – I am trying to control voltage with an opto-triac display. This is my hardware circuit shown in below in which used components like MOC3021 (OPTOCOUPLER), BT-136(TRIAC), 4 SWITCH(BUTTON), CRYSTAL 20 MHZ, PIC16F72 (MICROCONTROLLER), and a 7805 and 16X2 LCD. Read more

PIC18F4431 PCPWM signals are not good. I am using a PIC18F4431 with 16 MHz crystal and using its PCPWM module to generate 3-phase SPWM signals but the signals are not good. The only doubt that I am having is that the ISR code is taking more than 62.5us to execute once. But even if this is true, then PWM0, 1, 2, 3 should be good but they are also not good. I see signal shifting and when signals reach PWM duty 0 it suddenly becomes PWM duty 100%. Read more