Am I still alive? Aparently! Happy 2022, people!
CircuitMess continue with their interesting electronic DIY packs for the whole family. In this case, a small mixing table, capable of mixing two audio tracks, being able to apply filters to each of them. Based on an ESP32-WROOM, it has the same features as Spencer (dual-core microcontroller with 448 KBytes of ROM and 520 KBytes of RAM, 802.11n WiFi and Bluetooth 4.2).
The pack is similar to the previous ones from CircuitMess. As soon as you open it, you are presented with the different pieces to assemble the device: The motherboard, with almost everything already pre-assembled being SMD, a small microSD with some test music tracks, the speakers, bags of parts to be soldered, screws, button caps, and the clear plastic case.
The box 
The contents 
The motherboard 
The speakers. Hmm… fuet sausage… 🤤 
Miscelaneous pieces: LCD, minijack, linear potentiometers, button caps… 
Mixed screws, rotary encoders, microSD card reader… 
And last: the case and more button caps
I’ll not go into a lot of detail of the assembly process, like other times, since you can check a better guide than I could do ever do on the official website. The first thing is to solder in place the female minijack connector, which serves as a secondary audio output, in case you do not want to use the built-in speakers. Unfortunately, the audio output is mono, but if you’re good at music you can still create something interesting 😊.
The audio minijack, once soldered
Next are the two buttons that serve as “play” for both audio tracks. I don’t know if they have a specific name on the mixing table world. Music is not my thing 😅.
The play buttons
Next are the linear potentiometers. The two that are mounted vertically are the volume control of the two tracks. The horizontal one is the crossfader (quite a name for the “mix” control slider).
The three potentiometers
The next step is to solder the seven rotary encoders. What is that rotary encoder? Well, it is quite similar to a rotary potentiometer, you know, like the volume knob of the old radios, but these have free rotation for both sides, without limits, in addition to being able to be pressed, to give another function. The three on either side will take care of the track effects. The middle one is used to control the menus.
All seven rotary encoders soldered in place
Next step: solder the pins to the LCD screen. Aparently it has a resolution of 160×128, with SPI communication. It has a very good color range, and perfect viewing angles. It’s amazing how far LCD modules have come, even those designed for DIY projects 😊.
The LCD screen, with its pins soldered
And the last step: soldering the LCD to the motherboard.
The board ready for action
20 minutes and a lot of frustration later (separating the protective film from the case pieces), it is ready 😂. The rest is connecting the speakers and attaching the button caps.
The device all assembled
Now I could post a demo for you, but … My musical skill is non-existent, and I think I would lose readers if I do it … 🤣. You can check this video, from someone who has a little more skill:
See you in the next post!
