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Start of a blog - KaRadio Project

Hello everyone !

I decided to start a blog to keep a track of my electronics stuff I want to build.

I found the KaRadio Project, that aims to build a webradio - you know, the thing, not the stream. A real object that connects to the Wi-Fi and plays your favourite radios.

Some useful links :



As I tried a first prototype, I was really amazed what the main chip, the ESP8266, was capable of. So I decided to buy second-hand stuff in flea market to build a nice little webradio.

For the moment, I have my prototype working, but most of the work lies ahead : adding control through a second microcontroller (MCU for short), adding buttons, pushing everything into a case, adding energy support... heh, I'm hyped !

Nonetheless, I will have to wait a little because my second MCU (another ESP8266) is used for some exams I still have to pass. So I'm cautious not to tamper it while it works for my exams.

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Flashing an STM32 "Blue Pill"

Flashing this STM32 "Blue Pill" board took me 5 hours.

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Since it's quite complicated, consider the following as a tutorial to set up your Blue Pill. I tried different things, the following has worked for me.

Before doing anything software-related, while reading the Blue Pill page …

KaRadio DVT-01

I packed everything in my little case.

It's really a mess in there, with cables flying around and every card floating, not fixed on the inside. But it looks quite cool ! I removed the old radio antenna to use its hole to pass my USB cable.

Here's how it looks !






As you can see, I let the rotary knob (it's a simple angular potentiometer, in fact) from the amplifier out. It holds with a little nut that was provided with it. The buttons you can see are all fakes, they belonged to the old radio and I forgot to remove them (in fact they're simply glued to the back). 
Maybe I'll find some tools to make a nice-looking front panel when my stuff arrives. I'll ask people around me to lend me their tools...  In the end, the radio would have a 20x4 LCD screen to display artist + title and useful infos (like the IP or the volume when you change it from the website, maybe). I think I'll need two more buttons to change the station. I won't bother myself to add a volume…

Adding some speakers, part 2

I added the audio transistors.

Before diving into this modification, I wanted to see how deteriorated the sound is when you try to link everything on the same power supply WITHOUT transistors. So I made this little video. You can hear the difference !



First, I noticed that my three little wires (on the output of the VS1053) were badly soldered and caused a short-circuit somewhere. So I removed them, and replaced them with a naked Jack plug. (I took it from a selfie stick. True story. These selfie sticks have an audio Jack plug to be able to take a shot from a button near the hand, that acts just like a button from headphones with mic. End of the story, back to business :p )

I wired the output of the VS1053 to the input of the transformers, and I wired the output of the transformers to the input of the PAM8403 (the amplifier). Since on the input and on the output, they have common ground between the two channels, I kept the common ground. You can see a rough scheme below (the "Aud…