[Podcast] From Corporate World to Freelancing to Running a Hardware Startup


This podcast was conducted and hosted by John Teel from Predictable Designs, to see the original post please click here

In this episode of the Predictable Designs Podcast I speak with Roberto Weiser of Developpa.

Roberto is an electronics engineer that started work in the corporate world but wanted more freedom. So he left his life in a cubicle to become a full-time freelance engineer.

Eventually, he decided to develop his own product which is a low-cost air purifier. Roberto faced some unique challenges being located and selling in a foreign country (Thailand).

He also faced various other unique challenges that required him to be adaptable in order to deliver his product as promised.

This is a great episode with tons of great lessons learned that you don’t want to miss!

You can listen to the podcast on Stitcher

Everything you need to know about buying an Air Purifier

Buying an air purifier can be very confusing, especially if it’s your first time and the only thing you know is that you want clean air.

Air purifiers are machines that range from expensive top of the line full-featured home appliance with WiFi connectivity to very simple and affordable devices that just focus on the main function of removing PM2.5 and PM10 from the air such as our AirCleaner Personal.

Continue Reading “Everything you need to know about buying an Air Purifier”

Tiny Hall Sensor Module for Current Sensing

current sensor

Current and voltage are probably the most important electrical properties in any electrical circuit. They are the cornerstones of every other parameter and the first properties you look at when designing a circuit.

As you can imagine, for dynamic circuits, it is quite important to know the voltage and current at certain points in order to control the device operation or trigger certain action as well as calculate the heat dissipation.

Like voltage, current can a constant value (DC current) or a varying waveform oscillating at a certain frequency (AC current).

To measure current there are two popular ways of doing it: by measuring voltage drop on a resistor or by sensing a magnetic field in a conductor.

In this article, we will focus on how to sense a magnetic field in a conductor with the idea of measuring AC current using a tiny, cheap circuit.

Continue Reading “Tiny Hall Sensor Module for Current Sensing”

Arduino Board Design for Custom Projects

solar charger arduino

Believe it or not, the Arduino is one of the wonders of the modern world. It made electronics design and prototyping accessible to everyone by removing a lot of the initial entry barriers such as expert knowledge in C programming and hours of reading datasheets and application notes.

The power of the Arduino rellies in its communities that make good quality software libraries and join forces to make the platform easier and more powerful.

15 years ago, if you wanted to do a WiFi connected device that broadcasts information to another device, you will surely need a team of skilful and experienced engineers. As of today, by buying some modules and following tutorials online, you can achieve the same result.

But what happens when you have your proof of concept Arduino prototype working and want to make it smaller so it fits a sleek enclosure and takes away unnecessary components to make it cheaper?

You need to make your own PCB.

In this article, you will learn how to create a circuit that you can program with the Arduino IDE and works the same as the proof of concept prototype but in a custom-built PCB.

For this tutorial, 2 different MCUs will be reviewed. The ATMega328P from the Arduino UNO R3 and the ATTiny85/45/25, another popular MCU that can be used with the Arduino environment and is cheaper than the ATMega328P.

Continue Reading “Arduino Board Design for Custom Projects”

Freelance as an Electronics Engineer


In this article, I would like to share with all readers about my experience so far working as a freelance electronics engineer.

I have only been in this game for around 8 months, still learning a lot, making mistakes and improving.

I have divided this article into different sections of interest that envelope the whole package of what it entails to work as a freelance electronics engineer.

Continue Reading “Freelance as an Electronics Engineer”

Transformerless PSU, round 2

transformerless PSU

A few months ago, in the article Transformerless PSU, is it worth it? two ways to convert AC mains into usable DC voltage were analyzed in terms of cost, space and performance.

These two types were the traditional step-down transformer approach and a transformerless design that uses the property of reactance of the capacitor to create a voltage divider and effectively step-down the voltage.

In this article, we will analyze a third way to convert AC mains into DC voltage to power small electronics. Continue Reading “Transformerless PSU, round 2”

Beginners Guide: First Design with the dsPIC33E MCU


This post was originally published on Predictable Designs, the original article can be found here

If you are designing an electronic product, chances are that it will have a microcontroller (MCU) embedded into it.

In order to control, process, easily change parameters of the design on demand and keep the design tidy and relatively low complexity, it is unpractical to approach a solution using purely discrete analogue and digital components. For this reason, a natural choice is the use of a microcontroller. A microcontroller is basically a computer shrunk to a chip. It contains a CPU, memory, I/O pins and peripherals, all in a single package. Continue Reading “Beginners Guide: First Design with the dsPIC33E MCU”

Shenzhen Overview as an Electronics Designer and Maker

shenzhen taxi driver

Did you know that there is a place in this earth where electronics and product development is not a weird thing that can only be found in engineering firms, universities and some smart but awkward dude’s garage?

During October 2018, Developpa had the opportunity to experience this reality by visiting the so-called “Silicon Valley of Hardware”. Continue Reading “Shenzhen Overview as an Electronics Designer and Maker”

Current Source to Measure DC Resistance of a Wire


Have you heard of a current source before? In electronics, when you hear the word source, it means that part is “giving” or “providing” something, in this case, a current. The opposite of sourcing is sinking, this means that part is “taking” or “demanding” something. Continue Reading “Current Source to Measure DC Resistance of a Wire”