Hello, my name is Daniel, and I make things! Join me in this exciting journey exploring the world of computers and electronics


The Amp Hour

Hey guys, this is a quick post where I want to share a great podcast that I listen all the time called “The Amp Hour“.

Quoted from their about page: “Dave Jones from the EEVblog in Sydney (Australia), and Chris Gammell from Contextual Electronics in Cleveland (USA) discuss the world of electronics design in an hour long(ish) weekly show, recorded “live” without editing or a mute button!

If you are into electronics (which obviously I am), it’s a much listen show!
Check it out on the link below 🙂

The Amp Hour


Build a 3.5mm Audio Switch

audio mux p2

I moved to Berlin a few months ago to start working as Lead Electronics Engineer at UNU Motors. As soon as I found my own place (after spending three months apartment hunting), I decided to buy a good audio monitor, so I could listen to music and watch videos with a decent audio quality. My choice was a BX5 M-Audio audio monitor, great speaker at a very good price. The only annoying thing is that every time I wanted to listen music from my computer, I had to take the P2 plug from the RaspberryPi (running OSMC) and connect to my mac, and vice versa… To fix this problem, I decided to make a small PCB where I can plug everything together and then flip a switch to toggle inputs.


Backup and Restore Raspberry PI SD Card

If you are like me who is always trying different linux builds for Raspberry Pi or keeps messing up with Kodis configurations, this post is for your. I will teach you to make an perfect image of your SD Card so that you can simply go back to the last image, without having to install everything again from scratch.

If you don’t know how to install any linux distribution for RPi, I suggest you to follow this guide HERE

Backup

  • First thing after you insert the SD Card in your computer is to check what is the device’s location. Open a terminal, then run:
    diskutil list

    diskutil to check out raspberry pi sd card

    In my case, the SD card is in /dev/disk3. Remember that you are looking for the disk (not partition) of your SD card, so it would be disk4, not disk3s1.

  • Unmount your SD card by using the disk identifier:

    diskutil unmountDisk /dev/disk(disk# from diskutil)

    for example, in my case:

    diskutil unmountDisk /dev/disk3
  • Clone your SD Card to a file on your computer by using the following command:
    sudo dd if=/dev/disk(disk#) of=my_rpi_backup_image.img bs=4m

    you can change my_rpi_backup_image.img to any other desired name you want. Also the above process can take a few minutes to complete.

  • Now you can store your backup file anywhere you want for further restore.

Restore

  • Follow the first two steps described above and make sure you have the disk unmounted.
  • We can restore our backed up file to the SD Card, go to the folder where the image file is located and run on the terminal:
    sudo dd if=my_rpi_backup_image.img of=/dev/disk(disk#) bs=4m

    Same as before, this process can take a few minutes to complete, so you can go have some coffee while your computer finishes the job.

    Once it’s done, simply remove the SD Card from your computer, insert it to your RPi and turn it on, it will boot with the system the exact same way as it was before you saved it.


Round Corner PCB with EagleCad

Quick video showing how to create a PCB on Eagle Cad with round corners.
This is the way I do it, there are probably many different ways to do the same, if you know a better one, please share!


Altium Designer Tip & Tricks

altium logo

While Altium Designer is a relatively easy program to start working with, there are so many tricks, shortcuts and extra options to be discovered (which keeps me excited to always learn more!). I decided to create some kind of cheat-sheet for personal reference and I believe that it can also be helpful for other users out there.


Virtualmin: Backups to Google Cloud Storage

Virtualmin plus Google Cloud Platform

For a while I have been running a few websites using Virtualmin under CentOS. It’s a great free Web Hosting Control Panel application that helps you to manage your server without having to do it manually. It contains Apache, MySQL, proFTPD and much much more.

As I am a backup freak I have been backing up my server to Amazon S3 for a while. Amazon backups costs around $0.03 per GB, not that bad, but a few months ago I switched to Google Cloud Storage which has a technology called Nearline costing only $0.01 per GB (yes, 1/3 of the price!). The only disadvantage comparing to S3 is that the files retrieval takes a few seconds instead of milliseconds, as I am not serving this file on websites, and I really don’t mind waiting a couple secs to have the download link ready.



Arduino Crash Course: Get up and running in 1 hour

Have you heard of the Arduino? Its a small but powerful micro-controller that can be used to create many amazing things. An Arduino can be used to sense its own environment, connect and communicate with the Internet, manipulate devices around it, send messages, and much much more. Last year, over 700,000 hobbyists were using and contributing to the Arduino environment.

This course is designed to take you from 0 to 100 with Arduino in less than an hour. At the end of the course, you’ll be fully familiarized with Arduino and ready to build your own applications and devices. Ideally, this course is for beginners who want to get their toes wet with the Arduino system but those already familiar with Arduino can still learn from the techniques used in this course.

What you’ll learn in this course:

– How to setup the Arduino software and start outputting code
– How to understand and write code that your Arduino can understand
– How to setup Serial communication
– How to use a breadboard, and RGB sensor, and a LED Pin.
– How to create a variety of functions that interact with your Arduino
– How to create a device that detects your rooms temperature and changes colors accordingly.

ALL IN LESS THAN ONE HOUR!


Submenu item to Custom Post Types on WordPress

This is my first post under “Today I Learned” category, where I will post tips and code snippets about solutions to some problems I found while working on my projects.

Right now I am creating a custom WordPress plugin to interact with Campaign Monitor API. In the wordpress admin panel you have a Custom Post Type called “Email Campaigns”, and that’s where we want our plugin to add a submenu.

To get the right menu item to add the submenu, you need to check the URL that it takes you. For example, by clicking on the “Email Campaigns” button, it loads the page: http://www.domain.com/wp-admin/edit.php?post_type=email-campaign. So the item that we will use will be ‘edit.php?post_type=email-campaign‘.

The function below adds the submenu to that Custom Post Type:

And this is the result:

Before:

email_api_after

After:

email_api_before


Custom jQuery Slide Button

The idea of this code is to create a button with a cross on the right side and when you click, it rotates the cross and expands a hidden div. To slide up you can click on the button or on a round circle on the bottom of the div.

Everything was made using HTML, JavaScript and CSS.

You can also check a demo here.

button example