CHESTER-C5

This article describes the CHESTER-C5 carrier board.

Module Overview

CHESTER-C5 is a custom carrier board for CHESTER-U1 designed as a NB-IoT / LTE-M gateway for connecting arrays of 1-Wire sensors (i.e. DS18B20) equipped with Lithium-Ion battery backup, implements a step-down DC/DC converter providing power from an external 6-28 VDC line (VIN) or 12V solar panel. It allows to measure input DC voltage, QWIIC interface can by used for connecting OLED display.

The board implements the Maxim DS2482S-800+ providing 8 independent 1-Wire channels on CHESTER-X slot A. Slot B can be extended with the CHESTER-X1 providing another 8-ch 1-Wire or any other CHESTER-X module.

CHESTER-C5 fits with the Polycase WH-04-02 enclosure.

Technical Specification

Input DC voltage range (VIN): 6-28 VDC, suitable also for 12-18V solar panels*
Nominal battery voltage: 3.7 V
Battery charging current: 200 mA
Battery idle current consumption <10 μA (without CHESTER-M)
Recommended battery type for outdoor use: Samsung ICR18650-22P**
Operating temperature: -40 to +70°C (without Li-Ion Battery)
Storage temperature: -40 to +85°C (without Li-Ion Battery)

*Optimal photovoltaic solar panel for CHESTER: 12 V / 10 W

**Appropriate for solar panel application, charging temperature range -20 to +45°C, discharging -20 to +70°C

Battery charger and protection circuit

CHESTER-C5 implements the MCP73833 charger IC and the AP9101C protection IC protecting the battery by detecting overcharge voltage, overdischarge voltage, overcharge/discharge current.

caution

For initial start powering from the battery without DC input power supply it is necessary to long pres the Bypass button (BYPASS).

Module drawing: top

Module drawing: bottom

Module drawing description

Position	Name	Signal Description
A1	CHESTER-U1	CHESTER-U1 soldering slot
A2	CHESTER-X A	CHESTER-X soldering slot A*
A2	CHESTER-X B	CHESTER-X soldering slot B
A3	CHESTER-U1	CHESTER-U1 soldering slot
BT1	BATTERY	18650 Li-Ion battery holder
JP1	APP SWD	Application MCU SWD / debug connector
JP2	NET SWD	LTE Modem SWD / debug connector
JP3	1-Wire A	Integrated 8-ch 1-Wire interface terminal
JP4	I2C	I2C interface terminal
JP5	VIN	6-28 V DC Power Input terminal
JP6	SYSTEM	CHESTER SYSTEM JST connector
JP7	QWIIC	QWIIC connector (i.e. for OLED)
JP8	X slot B	CHESTER-X slot B terminal
JP9	BT/LED	External Button + LED JST connector
JP10	X slot B	CHESTER-X slot B JST con
JP11	TAMPER	Tamper input (normally open)
JP12	A1-A4	1-Wire A1-A4 + 4xGND RJ-45 con.
JP13	A5-A8	1-Wire A1-A4 + 4xGND RJ-45 con.
JP14	GND	Terminal with 8xGND
JP15	GND	Terminal with 8xGND
JP16	BATT	External battery or PPK input
JP17	VIN	6-28 V DC Power Input JST connector
JP19	1-Wire A	Integrated 8-ch 1-Wire interface JST con.
LED	RGY LED	RGY LED indication
S1	BUTTON	CHESTER button
S53	BYPASS	Battery protection bypass button**