Roll your own secure Dropbox replacement

Dropbox is a great software that I have been using for almost 10 years. It has helped me a lot during university, sharing project files, backing up my thesis and much more. It is a great service, but it also comes with a lot of problems regarding security and transparency (I will not get in-depth here). You can check for example, this article, or this one (there are many more if you look for it).

With this security issue in my mind, I decided to roll my own Dropbox-like service. The main difference is that I will know where all files are and that I am the only one with access to the unencrypted files. After building my own simple infrastructure, I decided to write a quick tutorial showing my solution and how you can create your own! Let’s get started…

The main software that we are going to use is called Resilio Sync (previously BitTorrent Sync). It takes care of all the syncronization between computer, mobile and server, just like Dropbox.

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A Better Serial Monitor

Today I would like to talk about a very interesting piece of software that I have been using in the past few weeks, called Serial Port Monitor (version 7.0) by Eltima Software.

This software is perfect for when you are developing an application that has a massive amount of information going through the Serial Port. I am currently using it to analyze diagnostic data from one project. Is is great that you can easily save messages for a later use in its own .spm file format.

serial port monitor

serial port monitor

On the image bellow, you can check the windows that I am currently using: “Terminal View”, showing exactly what is coming from the Serial Port. “Dump View” that shows timestamp, the hex data and the message, and the “Table View”, showing the captured data from the developer’s point of view: it presents the table consisting of the recorded IRPs. Each row represents one IRP and each column represents one single part of IRP. It is interesting to point that the Serial Port Monitor doesn’t block the serial port while in use, meaning that another software can be “blocking” the port and you can still analyze all the data.

serial port monitor

In case you wanna know more about it, check the Wiki!

This is a great piece of software, and I am really impressed by the quality of the products from Eltima. I will probably do some more review in the future!

If you are an embedded systems engineer, you should check it out!!!

Automating screenshot sharing on Windows

One thing that I really liked about mac was how easy it was to generate a screenshot from my screen and share with people. Now that I am pretty much a full-time windows user (besides all the time I spend on a Linux terminal), I needed to find an easy and fast way to share screenshots. And that is where Greenshot comes in handy!

The plan:
A keyboard shortcut to select a region of my screen, automatically generate the image, upload it to my server on a specific FTP folder (can also be done with rsync) and copy the shareable URL to the clipboard.

Step 1: Download Greenshot at and install it.

Step 2: Download and install NCFTP from (NcFTP Client 3.2.6 for Microsoft Windows). After installing it, the ncftp executable files are going to reside on C:\Windows

Step 3: Create a .bat file with the automating code below (changing yourdomain, ftp user and password).

Step 4: Configure greenshot:

Change the path where you save your screenshots on your computer, but the important thing is to change the “Filename pattern” to:


and uncheck “Copy file path to clipboard every time an image is saved“, this part is important!

Go to Plugins tab, click in “External command Plugin” and “Configure“.

Create a name for your automation. On command, link to the .bat file you created and make sure the “Argument” is


Done, now whenever you take a screenshot, it will automatically upload to your server and copy the URL to the clipboard automatically, making it super fast and easy to share anything on your screen 🙂

HC-RS04 NewPing Class

sonar non blocking sonar

Just finished writing a small C++ class to work with multiple HC-RS04 sonar transducers with a non-blocking way with the NewPing Library.
In this exact code I connected two sensors, but you can add as many as you like.

To add new sonars, just create a new instance of it adding the echo and trigger pins.

Sonar sonar1(2,3);

Here is an example with some NeoPixels, just for fun:


Quickly sharing 360 pictures

Last black friday I got a LG 360 Cam, a good cost-quality 360 camera. The only problem I am having with the camera is that there isn’t a good solution to where I can share the pictures (if you have a good solution, please share!). Google has released a VrView script that makes it much easier to embed 360 pictures on websites, but you still need to edit some html code.

I decided to make a super simple website that renders pictures uploaded to imgur (saving some space and bandwidth on my server) that anyone can use to easily share 360 pictures with family and friends.

After understanding how the Googles VrVire works, I could transform this:

Into this:

To share the 360 pictures, you need to upload them to and get the picture-id. For example, the picture above is located at where up6aRXr is the picture-id. With the id in hands, you can share this url:

for the past example:

The website should open with the image showing in full-page, and same URL you can share on Whatsapp or anywhere else (it is mobile friendly!)

Maybe in a near future I will improve it, making it easier to share from within the phone and also creating galleries, what do you think? Ideas?

Cheers! 🙂

NeoPixel 24 & HC-RS04 Sonar Support

sonar neopixel 01

I am currently working on a project that involve using a HC-SR04 Sonar sensor to control the lights of a Adafruit NeoPixel 24 Leds Ring. Yesterday I quickly designed a 3D model with DesignSpark Mechanical that I am using to center the sensor inside the led ring. I have also added a few spaces where the cable can pass though without disturbing the flat surface.

You can download it from GitHub, and there will probably be updates on the design in a near future.

What do you think?

Check this cool 3D preview by GitHub:

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Altium Tip: Smooth edges with Teardrops

Teardrops is a really nice feature present in Altium, where it analyzes all the traces and try to smoothen the edges of the connections. Most users don’t know that this feature exists, and even if doesn’t add a major change on the design it can certainly improve the quality of your project, especially if you are working on high-speed or high-power electronics.

altium teardrops

To access the menu, while editing your PCB, go to Tools >> Teardrops… (or simply press t + e).

Bellow you can check a random PCB design with and without Teardrops:

altium teardrops before

altium teardrops after

Interfacing two Adafruit MMA8451 via I2C

This week I had to interface two accelerometers (adafruit MMA8451 breakout boards) into one Arduino board.

On Adafruits website, they write that you can address the sensors with 0x1C by adding a pull-down resistor on the “A” pin, or 0x1D by connecting the
“3Vo” to a 3V3 source. What they don’t tell is how to use them both at the same time, which gets clear once you take a look at the Adafruit_MMA8451 class within the library file Adafruit_MMA8451.h.

bool begin(uint8_t addr = MMA8451_DEFAULT_ADDRESS);


Here you have a simple code based on the library example, but adding the two sensors: