Cheap and powerful 50 cents microcontroller | EFM8 Family

This is a step-by-step tutorial on how to setup and program an EFM8BB10F8G-A microcontroller or any other EFM8 Busy Bee microcontroller family from Silicon Labs. It is assumed that the reader knows the C programming language and basics about microcontrollers.

Why would you want to learn to use another microcontroller when there are many tutorials and libraries on popular MCU's such as AVR and PIC? Well, because they are much more cheaper but performant nonetheless - on Farnell you can buy them for less than 50 cents - and also are pre-programed with a bootloader making easy to program them using any USB to serial converter.  Compare that to Attiny13A which is around the same price but with half the pin count, less speed and peripherals. Just see the features bellow.

How to build your own USB to UART serial converter using FT232 with voltage level shifting

The board includes 500mA fuse protection, EMI filtering, power LED indicator, RX and TX LED indicators, and a voltage level shifter that makes it compatible with 3.3V and 5V boards. This way you don't need to check the jumper if it outputs 5 or 3.3V so you don't risk burning your microcontroller. It works with both voltages.

Update: 2024, March, 6: I made another serial adapter build around FT231 which require less components since it is 5V tolerant and is also cheaper. It is part of a development board: https://www.programming-electronics-diy.xyz/2023/06/breadboard-development-board-for-avr.html#USB_Interface.

EAGLE CAD Tips | How to Add Custom Image Logo to Your PCB

Adding a custom image logo to your PCB can make your project look more professional. In the following video I will demonstrate how you can quick and easy import an image in Eagle CAD and place it on your PCB. You can place graphics on copper layers to be etched or on silkscreen to be printed.

In this video I show as an example a USB to UART board. Eagle expects a Bitmap image with less than 256 color depth.The text image was made in Inkscape and since Inkscape can't export Bitmap (.bmp), I exported the image as PNG, then using IrfanView I lowered the color depth to 2 colors and saved as Bitmap.

How to use A4988 stepper motor driver module tutorial

A4988 stepper motor driver module

This driver can be used to easily control a bipolar stepper motor or a uni-polar stepper connected in a bipolar mode. Can output up to 2A per phase (with a heatsink) and works with motor voltages from 8 to 35 volts.

• Simple step and direction control interface
• Five different step resolutions: full-step, half-step, quarter-step, eighth-step, and sixteenth-step
• Adjustable current control lets you set the maximum current output with a potentiometer, which lets you use voltages above your stepper motor’s rated voltage to achieve higher step rates
• Intelligent chopping control that automatically selects the correct current decay mode (fast decay or slow decay)
• Over-temperature thermal shutdown, under-voltage lockout, and crossover-current protection
• Short-to-ground and shorted-load protection

Library for A4988 stepper motor driver using timer interrupt

Update 4, October, 2023: I have made a new library for controlling stepper motor drivers that supports multiple motors and has a better acceleration algorithm. It can also coordinate xyz steppers.

This library is designed for AVR ATmega328 microcontroller, but with few adjustments can work with any AVR microcontroller with at least 3-4 Kb of flash program memory.
At the moment only one motor is supported.

Features

• the interrupt can be triggered by Timer0 or Timer1
• automatic microstepping mode selection
• can work with constant and very low speeds
• accelerated speed mode, with separate acceleration and deceleration settings
• can work with only one pin of the microcontroller if the rest are hardwired

Characteristics:

Features	Program Memory	Data Memory (SRAM)
All enabled	3552 bytes	40 bytes
Acceleration, no microstepping	3088 bytes	40 bytes
Microstepping, no acceleration	2104 bytes	14 bytes
No microstepping, no acceleration	1724 bytes	12 bytes

Compiled using avr-gcc (WinAVR 20100110) 4.3.3 and -Os optimization level and MATH_LIB = -lm.
If MATH_LIB = -lm is commented out in Make file, the memory with all functions enabled is 6520 bytes program and 304 bytes data memory.So allways uncomment MATH_LIB = -lm.

Homemade Cheap ESD Safe Electronics Storage Box

Storing and finding electronic components can be a pain. I tried many solutions over the years until I found a solution that suits my needs - making boxes from 2mm plastic sheets. The cost is very low and can be made in whatever sizes you need.

Salvage a VFD from a broken DVD

I had a broken DVD Player Philips DVP5960 so I thought to use the display with my other projects. The display is a Vacuum Fluorescent Display or VFD for short. This VFD is mounted on a front board alongside with an IR receiver and 4 tactile buttons and it is controlled by the ET16312N driver chip. You can use this front board for a digital clock or anything else that needs a display and a few buttons. The buttons can be desoldered and positioned elsewhere extended by wires.

To  create all this circuitry from scratch would be difficult. The ET16312N driver needs +5V, +12V and -24V. Also you would need to create an AC signal, multiplex the grids, drive the anodes, etc. but all this is already build for oyu on the front board. The power supply from the DVD Player can be used but I want to power the VFD from batteries so I will try to make a power supply myself.
The weird thing is that on the 12V line the VFD driver draws about 53 mA even if the display is off or dimmed. On -24V it draws about 6 mA. So yeah, it is not well suited for batteries unless you physically turn of the power using a transistor controlled by the MCU when the display is in standby.

Philips DVP5960 Front Board together with Crapduino