Tag Archives: Davide Gironi

ATmega8 MCU goes guitar pickup winding

Davide Gironi has created a DIY guitar pickup winding machine powered by Atmel’s ATmega8 microcontroller (MCU), a 12V (1200rpm) DC motor and a L298N chip board.

Key features include a wind counter, slow startup, automatic stop, configurable motor speed and configurable winds. 

The unit’s winder is also equipped with an LCD display that shows current motor direction, rotating speed of the pickup and the total, current wind counter.

According to Gironi, users can configure:

  • Motor direction – clockwise, or anti-clockwise
  • Direction of the wind counter to increase – clockwise, or anti-clockwise
  • Motor max speed – from 1(min) to 100 (max)
  • Motor startup acceleration – from 1(min) to 100 (max)
  • Numbers of wind – from 1(min) to 99999 (max)
  • Auto stop mode – manual mode, or stop when all winds are done

“There are three buttons, SELECT, button UP and DOWN. To enter the programming mode, just long press SELECT button. Press SELECT once to change the programming parameter, button UP and DOWN to edit the selected value, then long press SELECT again to save new values,” Gironi explained in a recent blog post.

“If you are in building mode, to make the wind start press the RUN pedal, it will start with a slow startup, to stop the winder release the RUN pedal. The winding machine will automatically stops when the wind counter reach the configured number – and it can goes less than zero. If you disable the autostop mode, the machine will always count wind, independently by the direction chosen.”

Interested in learning more? You can check out the project’s official page here.

Video: SPL dB audio meter with an AVR ATmega

Davide Gironi has designed a simple sound pressure level meter (SPL) dB audio meter using an AVR-based ATMega8.

As Gironi notes, a sound level meter or sound meter can probably best be described as an instrument which measures sound pressure level.

“Sound pressure level (SPL) or sound level is a logarithmic measure of the effective sound pressure of a sound relative to a reference value. It is measured in decibels (dB) above a standard reference level. The commonly used reference sound pressure in air is = 20 µPa (rms) which is usually considered the threshold of human hearing,” he explained in a recent blog post.

“Keep in mind that 1 pascal will equal an SPL of 94 dB. Because the frequency response of human hearing changes with amplitude, a weighting have been established for measuring sound pressure. Usually the A-weighting curve is used. A weighting curve is a graph of gain across the frequency range (10Hz to 20kHz).”

On the software side, Gironi uses the Radix-4 FFT library with a matlab script for validation, with two processing scripts provided as a viewer for the data.

Interested in learning more? You can check out the project’s official page here.

Video: ATMega8 drives this brushless motor controller

A Maker by the name of Davide Gironi has designed a brushless motor controller powered by Atmel’s ATMega8.

As previously discussed on Bits & Pieces, the low-power sipping 8-bit AVR RISC-based microcontroller boasts 8KB of programmable flash memory, 1KB of SRAM, 512K EEPROM, and a 6 or 8 channel 10-bit A/D converter. The device also supports throughput of 16 MIPS at 16 MHz, while operating between 2.7-5.5 volts.

“Brushless motors have no brushes in them (duh). But what does that really mean? In order to spin the motor a very carefully crafted signal is sent through the motor coils in the stationary portion (called the stator), producing a magnetic field that pushes against permanent magnets in the rotor,” writes HackADay’s Mike Szczys.

“A big part of crafting that signal is knowing the position of the rotor. This is often accomplished with Hall Effect sensors, but can also be performed without them by measuring the back EMF in the coils not currently being driven. The AVR-GCC compatible library which Davide Gironi put together can be tweaked to work with either setup.”

You can find out more about Davide Gironi’s ATMega8-powered brushless motor controller on the project’s official page.