Voltlog #287 – Switching From Eagle To Kicad

Welcome to a new Voltlog, today I’m gonna talk a bit about my process of switching from EagleCad to Kicad. So i’ve been an EagleCAD user for years, I’ve practically learned how to do pcb layout in eagle cad so there is that emotional attachment to a piece of software because it’s what I used while developing this skill. And to be honest there wasn’t any better alternative years ago, Eagle was the first decent piece of cad software to offer a freeware license and it quickly became popular for hobbyists. It didn’t have all the bells and whistles of the expensive software like Altium or Candece but it did the job while being user friendly.

Since it quickly became popular for makers and hobbyists it also meant there was an abundance of support on the forums as well as many user generated scripts and libraries freely available. It was similar to the popularity Arduino got but it was never open source and if you needed some extra features like 4 layer layout or pcb sizes larger than 8x10cm you needed to pay for a license.

Voltlog #286 – How Is The Coronavirus Affecting PCB Production?

Welcome to a new Voltlog, I have a couple of projects in the pipeline right now that require PCBs and as usual I will be getting them from JLCPCB who have been sponsoring my videos for a while now and even if they weren’t I would still be ordering from them because I like how their service runs. But the problem right now as you may know is the Coronavirus infection. In order to contain the spread of the virus, companies in China have moved to a work from home scenario with only minimal required personnel present  on site. 

This coupled with the extended holiday which was issued after the spring festival means decreased manufacturing capacity which leads to long lead times as customers line up to get their PCBs manufactured.

So this video is more an update on the current situation because I am in contact with JLCPCB and I want to give you some info on the expected delays for pcb orders. Right now they offer production of 2 layer pcbs as well as smt assembly service and stencil production service but 4 layer, 6 layer and ENIG coated pcb manufacturing has been suspended until further notice.

Voltlog #257 – ESP32 PIR Motion Sensor With Deep Sleep & MQTT (revB part2)

In this video I’m gonna show the second revision of my esp32, battery powered PIR motion sensor. This second revision contains some optimizations to improve deep sleep power consumption as well as to fix some of the errors I had the first revision of the pcb.

Voltlog #249 – Making Some USB Serial Converter Boards With CH340E (part 1)

Welcome to a new video, today I’m building a bunch of usb to serial converter boards because if you are into electronics and microcontrollers you will for sure need a bunch of usb to serial converters to connect your boards to a computer for example.

The idea for building these boards started when I found the CH340E converter chip on aliexpress, I like several things about this chip, it was small because it comes in MSOP10 package, it was cheap at about $0.40 a piece and it requires minimal external circuitry, in fact it only needs an external bypass cap.

Voltlog #240 – ESP32 PIR Motion Sensor With Deep Sleep & MQTT

Welcome to a new Voltlog, in this video I’m gonna show you how I designed and built this board which functions as an esp32 based, battery powered PIR motion sensor. So I started by designing the circuit, I used some common building blocks, I added the ESP32 with it’s bypass caps, some test points and the programming circuit with auto-reset, I then added some connection points for the PIR sensor, an RGB LED because why not have a nice way to signal this is one of those very small digital RGB leds, it’s just 20x20mm, it’s connected to 3.3V even though it’s only rated for 5V so I’m hoping this is going to work even on 3.3, it’s also worth having a temperature/humidity sensor to also sense that in whichever room the node will be placed and finally the power supply circuit which is a simple low dropout regulator with an 18650 battery as the input.

I did not include a battery charger circuit on this module, because I wanted to keep things simple, I’ll have a battery socket so I can just remove the 18650 cell and charge it separately plus the whole circuit should run in sleep for extended periods of time giving me a long operating time so i wouldn’t have to charge the battery too often.

Once the schematic was finished I did the board layout in a hurry so it’s not exactly pretty or optimized

but I tried to move the esp32 antenna to the side, to place the PIR sensor in the top side as the module will probably sit vertically, I tried to place the temperature sensor in the bottom side to keep it away from any components that might get hot and also placed some isolation slots for the same reason.

You should check-out revB of this board, I made some improvements present in the video below.

Voltlog #229 – What’s The Smallest Digital RGB LED?

Welcome to a new voltlog, today we’re talking about RGB LEDs. Everyone knows and probably uses digital RGB LEDs these days because they’re convenient, you only need a single pin to control then, they can be chained one after the other creating long addressable RGB strings, you don’t have to worry about driving them with constant current, in fact they even have digitally controlled brightness settings so they’re pretty convenient.

Since these are digital, they have a built-in controller chip, and if we take a closer look at one of these LEDs which comes in a 5050 package, we can see the driver chip and the 3 LEDs red, green blue with their corresponding bonding wires. There are two popular drivers chips the WS2812 and the SK6812 and each of these might have different revisions as well. The WS2812 was the original one on the market and then the SK6812 appeared and is considered a clone of the WS2812 but brings some improvements. The SK6812 has doubled the pwm frequency at which it drives the LEDs which is always welcomed as it helps with reducing flicker and also the timing requirements are a bit tighter but existing WS2812 libraries should work fine with the SK6812.

Voltlog #95 – The New Raspberry Pi 4

Like I mentioned I’m the first to get this board, months before the official release date, this is an engineering sample.

I was lucky to have a good friend of mine, a childhood friend, that works at the raspberry pi foundation. He is the guy that did the layout of all the raspberry pi board you know. So I was having a chat with my friend this week when he showed me this and I just didn’t let it go until he asked the right guy and finally got the approval to let me show this thing on camera.

I’m not allowed to keep it because it’s one of the few engineering samples that exist but we can take a good look at it so let’s go to the bench for a close-up.

Here are some high-res images below, please credit with link to this page if you plan to publish them anywhere.

The new raspberry pi 4 board top The new raspberry pi 4 board top