SMP Gadgets

Software Finally it comes to the software session after a complete assembly. After trying several headless software, namely Volumio, Moode Audio, Hifiberry OS and Picoreplayer, I decided to go to Picoreplayer. This is not only because of the outstanding sound quality, but also a very user-friend interface (touchscreen) and numerous plugins available. Boot up sequence - Personally I like it quite much, it looks pretty cool on a 5" touchscreen :P Setting up Picoreplayer This guideline will walk you through the settings of Picoreplayer. The set up was based on Picoreplayer 7.0.0 but it would be pretty much the same for the latest version 8.0.0. I am not going to teach you how to flash the image to the SD card as there are lots of tutorials available. You may download the latest version 8.0.0 from Picoreplayer website: https://docs.p...

Power Supply Here comes to the power supply of the RPi, DAC HAT and the touch screen. It is recommended to supply 5V/3A to the RPi 4 and touch screen, together with DAC HAT and some buffer, 5V/5A would be a suitable option for the system. In this project I am using a 40VA R-type audio grade transformer with 8V/5A output capability. 8V is the RMS value without loading. The peak voltage is 8*1.41=11.28V, the low dropout IC requires >1.5V voltage differential, also considering 1.4V drop after the bridge rectifier, 8V output would be a suitable option (provided that decoupling capacitance is large enough). The power supply circuit is rather simple, LM317 sets the desired voltage, a PNP BJT serves as a switch to provide large current. Schematic and Layout Below shows the layout of the power supply circuit. The input and output are placed on the sa...

Introduction I have been playing with some kinds of DACs for several years and was satified with the performance until I came across the raspberry Pi 4. The sound produced by rasberry Pi is so musical and dynamic, and you can choose from different DAC HAT that you desire. After trying different headless operation systems, I decided to go for piCorePlayer which has Logitech Media Server (LMS) and SqueezePlayer built in. This tutorial will walk you through how to build a streamer / DAC player with linear power supply and a touch screen (Jivelite). Mechanical Design It is easy to design the layout of components in 2D, but quite difficult if you need to design a mechanical anchorage for a 5" touch display in 3D - stylish is of utmost importance, but strong and reliable anchorage also play an important role. Faceplate The dimensions of the case t...