Hardware

Overview

The Picoclick-C3 is - as the name suggests - based on the ESP32-C3 which is a 32-bit RISC-V processor running at up to 160MHz.

Features

• Pico size: 18x22mm

• MCU: ESP32-C3FH4

• Single button interface

• Two APA102-2020 RGB LEDs

• Embedded battery protection

• Embedded battery charging with status LED

• Optimized battery monitoring

• Extension port with two GPIOs and power pins

• Ultra low power device

• Includes an onboard chip antenna

Block diagram

Front side

On the front side there are mainly three things only: The 12mm button, two APA102-2020 LEDs and the 6p FPC connector. Additionally there are two soldering jumpers.

Back side

The back side is the main component side. It holds the USB Type-C jack, the ESP32-C3, the battery charging as well as the battery protection circuit, a voltage regulator, the antenna with its matching network and the power latching circuit. And the best: A golden logo :)

Technical drawing

Measurements in mm, grid is 0.5mm

• PCB: 18mm x 20mm

• Thickness: 1mm

• Corner radius: 2mm

Main components

Function	Component	Note
MCU	ESP32-C3FH4	Main processor, 4MB flash
Battery protection	XB6042I2SV
Battery charging	WS4518D	Charging current set to 20mA
Voltage regulator	MIC5504	3.3V LDO
LEDs	APA102-2020-256-8
RTC crystal	CM9V-T1A	32.768kHz
Main crystal	S2140000091070JY	40MHz, 2016
Antenna	SLDA31-3R400G-S1TF	2.4GHz
FPC connector	FH34SRJ-6S-0.5SH(50)

Pinout/Connection

Function	GPIO ESP32-C3	Note
APA102 SDI (LED)	GPIO7	Output
APA102 CLK (LED)	GPIO6	Output
Button state	GPIO5	Input
Battery voltage	GPIO4	Input, includes an 1:1 voltage divider
Battery voltage trigger	GPIO3	Output

Battery connections

Current consumption

All the current consumptions below are measured with my PowerProfilerKit 2.

Mode	Average current	Note
WiFi activated	74mA	Peaks can be up to 200mA
WiFi disabled and LEDs fading	27mA
Picoclick deactivated	2µA

The current consumption in active mode can be reduce with the following steps:

• Turn WiFi only on when really needed.

• Reduce CPU frequency. With the embedded clock (40MHz) you can set the frequency to 10, 20 and 40MHz. 10MHz is great for just LED applications.

• Reduce APA102 LED brightness.

Jumper

There are two soldering jumpers with two different functions. The BOOT and the USB jumper.

Boot jumper

The left jumper connects the boot strapping pin of the MCU to GND and therefore forces to enter the boot mode of the ESP32. More infos are described here.

USB jumper

The right jumper connects the USB voltage to the battery voltage, so that the Picoclick can be powered directly over the USB port without the need of connecting another power supply. The battery charger is not in use then (of course).

NOTE!: Do not connect a battery to the Picoclick if this jumper is closed, else you would destroy the Picoclick, your battery or both of them.