Everyone loves ESP32 chip, it's wonderfull chip from espressif with great functionality and really mature in software development side. This project most inspired by Odroid Go and Pocketsprite, so why making new one despite buy one of them? Well, i know those devices are great and have well community support, but some of them had some issue that i don't really like. Odroid Go had shared it's spi for both display and sdcard, and they need patched esp-idf version for it and sdcard not work very well in spi mode, at least for my experience. Then pocketsprite only have esp32 wroom module without psram and also without sdcard support so limited portability for save my collection of games.
Then i decided to design my own hardware based on both of them so i could port it's software to my own designed hardware then here i presented to you ESPlay Micro.
The board are designed for the following feature :
After releasing the project on the Makerfabs, some people looking for the case and then i decided to make an experiment how this case should be design.
After some iteration and made a bunch of failed 3D printed case ( I designed it with OpenSCAD), I decided to use FreeCAD which will be easier. when using OpenSCAD i need to measure the board precisely, but since i have an png and 3d model of the board, using FreeCAD should be precisely without measuring the real board.
Here some prototype of the case, this won't be the final version but i will update the stl file, so someone should not try the old stl files which will be trashed cause it's useless agains the latest board revision
@Makerfabs sent me 2 PCBA Sample last week, so i could work for the firmware this weekend. After upload the fw i just surprise the sound and button didn't works, i spent two hours to see what happened. I didn't make any changes on button, then after reads the datasheet there's different i2c address scheme between PCF8574AT and PCF8574T. Earlier prototype PCF8574AT was used ( salvaged from 1602 lcd i2c backpack ) and the address 0x38 was used, with this sample PCF8574T the address is 0x20, one problem solved.
The Sound is different case, after 3 hours struggled with the programming the problem is not the software but really bad typos on schematics, the resistor for R-C filter was wrongly typed from 1 Ohm to 1 KOhm, swap the resistor with the right one and VOILA the sound works. The Sound output are really clean on the headphone and very low noise output from the speaker, really satisfied with the result.
So... Yesterday I finished a revision design for next PCB. I will double check it before sending it to manufacturer. This time the prototype PCB will be produce by @Makerfabs.
Here the changes in this revision so far, i called this pcb-rev2.0 :
Audio amplifier chip would be replaced by PAM8403 and used only left channel since audio onboard speaker only mono. I used this chip because the that have inbuilt shutdown circuit and low noise audio profile.
Change layout audio blocks, so audio system will be in one block to reduce noise.
TP4056 li-ion charger replaced by LTC4054 since it smaller and less external components.
Add usb plug detect and charger status, it will be monitored by esp32 to charge management.
Add some ESD Protection on sdcard.
Moved all port to the bottom edge pcb so it won't interfere while play.
Long ago i used a quick and dirty hack of GoGo launcher made by odroid-go community member. Now i built from scratch an Launcher Software for Esplay Micro using UGUI library and add some capabilities like uploading file to device using web browser. checkout my github page for code.
While built this launcher i found a little bit flaw on hardware side, seems the LDO not enough current to supply whole board while wifi enable, backlight TFT are glitching and sometimes esp32 reboot cause of brownout detected, decreasing WiFi TX power seems solve for now, default TX power is 20 dBm and decreasing half of it to 10 dBm uses less power.