Engineers use the revered 555 timer IC so typically that some will ask, ” Why did not you simply use a 555?” when offered with an arbitrary circuit. Thomas Goff determined to run a contest: a 555 versus a microcontroller (PIC12) for DC motor control to search out out which answer was greatest! Goff designed circuits and a printed circuit board (PCB) for every contender.
The microcontroller was an eight-bit Microchip PIC12F1840 (PIC12). Goff selected this chip to maintain the struggle as truthful as potential because it is available in a through-hole DIP-8 package deal — just like the 555. To cut back elements, the MCU makes use of its inner oscillator. The opposite elements on the board are a 5V regulator, a transistor (to drive the motor), and passive elements.
Goff utilized a number of peripherals constructed into the PIC12. For instance, the ADC senses an incoming voltage to regulate the responsibility cycle of a PWM generator. Goff wrote the code utilizing Microchip’s MPLAB IDE and the PIC’s native C library. Nevertheless, you may repeat this experiment utilizing the Arduino framework.
The 2 contenders (📷: Thomas Goff)
The 555 circuit has two distinct phases. The primary stage makes use of the timer IC to generate a sawtooth waveform, which connects to the second stage. This stage contains a comparator that compares the sawtooth waveform to the (divided) enter voltage. The output of the comparator goes into an op-amp, which in flip drives a MOSFET that controls the motor.
The result’s two circuits that change a DC motor’s pace again on an enter voltage. However does it reply which method is greatest? Nicely, Goff has an opinion on the matter.
This step-by-step write-up of the microcontroller vs. 555 showdown consists of the schematics, instance movies, and (most significantly) outcomes!
Article paintings generously supplied by an upcoming artist.
