My journey with the Arduino PCB’s began a year ago when I purchased Chinese K40 Laser cutter and engraver from EBay which I upgraded with a Grbl controller based on the UNO R4. After experimenting with a stock Arduino UNO R3, I decided that I needed a better Arduino with at least one additional 16 bits PWM channel without an added price tag. Since I am controlling a CO2 laser, speed or additional processing power are not a requirement since the CO2 gas needs time to ionize and quality engraving takes time. Throwing in a huge ARM processor on 80MHz is not going to make a huge difference.
I did find a good candidate in the 328PB which is a more powerful sibling processor because of its extended features (additional ports, two additional 16bit timers, 2 USART’s) and it’s actually cheaper as well.
|Unique Device ID||–|
|2* Serial Interface||1* Serial Interface|
|2* SPI||1* SPI|
|2* I²C/TWI||1* I²C/TWI|
|27* Digital IO||23* Digital IO|
|3* 16Bit Timer||1* 16Bit Timer|
|10 PWM Channel (PD2 double used)||6 PWM Channel|
|Clock Failure Detection||–|
|USART Sleep Mode Wake up||–|
Since I could not find any new Arduino boards based on the 328PB, I decided to make my own R4 based on a R3 board. My first attempt was using a stock Arduino board and carefully removing its current Atmega 328 processor and soldering in a new advanced Atmega 328PB. Unfortunately, it did not work so I had a second attempt with another board which failed as well. I could program it but that was it, no ‘hello’ life sign from Grbl when starting it up. After carefully reading the Datasheet, I discovered that the manufacturer removed the so-called ‘full swing oscillator’ clock circuit in order to make room for the additional features and that the chip needed a high performance crystal rather than the cheap crystals or RC based circuits that are being utilised in the current clone Arduino boards.
Having little experience with surface mounted devices, I decided to take the designed the board to PCBway, a Chinese manufacturer of PCBs. They did the whole manufacturing job of my ten boards from PCB to SMD assembly for me. Unfortunately, I made a few mistakes in selecting the components from an online components catalogue, like a reset button which was too small in size and a wrong model header but that was easy to rectify by myself. It shows you never can rely on catalogues alone.
All ten boards worked immediately after installing Grbl! PCBway did a truly excellent job and the quality and finish is definitely professional. I could not tell this apart from the boards that I buy from commercial suppliers. Bella from PCBway did a great job in communicating with me during the production process and she even followed up after they delivered the boards via DHL.
Now I can use the CNC firmware Grbl on my laser and do 16 bits engraving. Can’t be happier and more satisfied!