ESPuino/PCBs/Wemos Lolin32

Tonuino-PCB based on Wemos' Lolin32

Introduction

After I've been asked many times to provide a PCB, I finally did so :-) It makes use of Wemos' Lolin32 which is the predecessor of Lolin D32. D32's advantage over Lolin32 is especially, that a voltage-divider for measuring battery's voltage is already integrated (fixed-wired to GPIO 35). However, as I wasn't aware of that when buying Lolin32 and because of now, that multiple Lolin32 are here on my desk, my reasonable intention was to use them. So things would have been a bit easier with D32 but in the end it works the same way with Lolin32. As per rev2 of the PCB, I added a 10 uF-capacitor to smoothen the battery-measurement. Ii's optional but be advised values measured are a bit more volatile without capacitor-stabilization.

Features

• Fits Wemos Lolin32 (not Lolin D32, Lolin D32 pro or Lolin 32 lite!)
• Outer diameter: 56 x 93mm
• JST-PH 2.0-connectors for buttons, rotary encoder, Neopixel, RFID, reset and battery (not 2.54mm pitch!)
• 2.54mm-connectors for MAX98357a and uSD-card-reader
• Mosfet-circuit that switches off MAX98357a, Neopixel, headphone-pcb and uSD-card-reader automatically when deepsleep is active
• All peripherals are solely driven at 3.3V! Keep this especially in mind when choosing uSD-reader. If in doubts use one without voltage-regulator (link below).
• If headphone-pcb is used, MAX98357a is automatically muted when there's a headphone plugged in and vice versa.
• If HEADPHONE_ADJUST_ENABLE is enabled and a headphone is plugged in, an alternative maximum volume is activated. I added this feature because headphone-pcb makes use of an amp that (probably) "allows" children to damage ears. This maximum volume can be set and re-adjusted via webgui.
• rev2: Reset-pinheader added. Can be used to connect e.g. a micro switch to it, so you can reset Tonuino even in battery-mode from the outside of the enclosure. Micro switch can be placed somewhat hidden at the enclosure.

Prerequisites

• If no headphone-pcb is connected, make sure HEADPHONE_ADJUST_ENABLE is not active.
• I used 390/130 kOhms-resistors as voltage-divider. However, make sure to use a multimeter to determine their exact values in order to achieve a better battery-measurement. They can be configured in settings-lolin32.h as rdiv1 and rdiv2. Hint: for Lolin D32's battery-measurement 100k+100k were used. However, I decided to change the ratio from 50/50% to 25/75% to have a "better" signal. 100/100 might be work as well; didn't test it.
• Make sure to edit settings.h according your needs.

Things to mention

• RFID: In order to avoid buying a 6pin-JST-PH-connector I used 2x3pin instead. This is because I already had ten of them (see link below).
• In contrast to Lolin D32, Lolin32 doesn't feature an integrated voltage-divider. That's why on the lower left there's a JST-PH2.0-connector to connect the LiPo-battery. Make sure to connect (+) to the left und GND to the right. From there you need to solder two short wires (5cm or so) onto the pcb with a JST-PH2.0-connector attached on the other side. This one needs to be plugged into Lolin32 (see pictures-folder). Please note: Lolin's JST-PH2.0-connector needs (+) left side and GND right side. Don't be confused if black/red-colouring of the JST-wires used seems "weird" because is reversed (black => (+); red => GND).
• Better don't solder Lolin32 directly to the PCB. I recommend to make use of female connectors instead (link below).
• When ordering a LiPo-battery, make sure to use one with deep discharge protection! This is really really really important!!!
• Doesn't (currently) support SD-MMC and RFID-reader PN5180

Hardware-setup

The heart of my project is an ESP32 on a Wemos Lolin32 development-board. Make sure to install the drivers for the USB/Serial-chip (CP2102 e.g.).

• MAX98357A (like Adafruit's)
• uSD-card-reader 3.3V only
• RFID-reader
• RFID-tags
• Neopixel-ring
• Rotary Encoder
• Buttons
• Speaker
• uSD-card: doesn't have to be a super-fast one; uC is limiting the throughput. Tested 32GB without any problems.
• JSP PH-2.0-connectors
• Female connector
• (optional) IDC-connector female 6pin for headphone-pcb
• (optional) IDC-connector male 6pin for headphone-pcb
• (optional) Mikro switch
• LiPo-battery (2500 mAh) with connector JST PH 2.0mm

Parts

• 1x IRF530NPbF (N-channel MOSFET)
• 1x NDP6020P (P-channel MOSFET)
• 1x 1k resistor
• 1x 10k resistor
• 2x 100k resistor
• 1x 130k resistor (can be replaced by 100k)
• 1x 390k resistor (can be replaced by 100k)
• 5x JST-PH2.0-connector (2 Pins)
• 3x JST-PH2.0-connector (3 Pins)
• 1x JST-PH2.0-connector (5 Pins)
• Female connector as socket for Lolin32, uSD-reader and MAX98357a
• (optional for headphone-PCB) 1x IDC-connecor female (6pin)
• (optional for headphone-PCB) 1x IDC-connecor male (6pin)
• rev2: (optional) 1x 10 uF capacitor (2.0mm-pitch)

Where to order?

I ordered my PCBs at jlcpcb. You have to order at least 5 pcs, which is only at 2$ + shipping. It took two weeks to arrive. If you want to have a look at the PCBs first (without having KiCad installed), visit Gerberlook and upload gerber.zip from the Gerberfiles-folder.

Do I need to install KiCad?

Unless you don't want to change anything: no! All you need to provide are the gerberfiles (gerber.zip) to your manufactur (e.g. jlcpcb). However, all Kicad-files used are provided as well.