3. Expansion Modules

CHESTER is an extensible device throughout the expansion modules (up to two) installed underneath the bottom side of the board (underneath the battery).

3.1. CHESTER-X0A

This module adds the possibility to connect external I2C peripherals. For instance, temperature/humidity sensor.

3.2. CHESTER-X0B

This module adds the possibility to connect an external ultrasonic sensor which can be used for water level monitoring.

3.3. CHESTER-X0C

This module adds the possibility to connect up to 4 external analog/digital signals (maximum voltage up to 28 VDC).

3.4. CHESTER-X1

This module adds the 1-Wire interface. It can be used to connect external digital thermometer or HARDWARIO Soil Sensor.

CHESTER-X1 pinout

Terminal

Signal

Description

x1

+V

Auxiliary positive battery voltage terminal

x2

GND

System ground

x3

VOUT

Positive power terminal for 1-Wire peripheral

x4

DQ

Data signal 1-Wire peripheral

x5

DQ

Data signal 1-Wire peripheral

x6

VOUT

Positive power terminal for 1-Wire peripheral

x7

GND

System ground

x8

+V

Auxiliary positive battery voltage terminal

CHESTER-X1

3.5. CHESTER-X2A

This module adds the 3 V TTL/CMOS UART interface.

CHESTER-X2A pinout

Terminal

Signal

Description

x1

GND

System ground

x2

VDD

3 V power

x3

RX

Serial data in

x4

TX

Serial data out

x5

EN

Peripheral data alert

x6

VDD

3 V power

x7

GND

System ground

x8

+V

Auxiliary positive battery voltage terminal

CHESTER-X2A

3.6. CHESTER-X2B

This module adds the RS-485 interface. For example, this can be used to interface Modbus peripherals.

CHESTER-X2B pinout

Terminal

Signal

Description

x6

B

RS-485 signal B

x7

A

RS-485 signal A

x8

GND

System ground

CHESTER-X2B

3.7. CHESTER-X3

This module adds the possibility to connect Pt1000 RTD thermometers in 4-wire (high-accurace) mode.

3.8. CHESTER-X4

This module adds the ability to power CHESTER from the external DC power supply. It integrates ultra-low-power DC/DC controller altogether with the ability to measure the input line voltage. Also, this module can measure 4-20 mA current loop input and implements 1-Wire master (the same functionality as CHESTER-X1).

The operating input voltage ranges from 5 VDC to 28 V DC.

CHESTER-X4 pinout

Terminal

Signal

Description

x1

SOURCE

Positive power terminal for current loop sensor

x2

SINK

Negative power terminal for current loop sensor

x3

GND

System ground

x4

VOUT

Positive power terminal for 1-Wire peripheral

x5

DQ

Data signal 1-Wire peripheral

x6

GND

System ground

x7

VIN

Positive input rail (voltage range 4-28 VDC)

x8

GND

System ground

CHESTER-X4

3.9. CHESTER-X5

This module adds the ability to measure external voltage in the range from -30 V to +30 V with the resolution of +/- 30 mV.

CHESTER-X5 pinout

Terminal

Signal

Description

x7

GND

System ground

x8

+VIN

Measured voltage -30 V to +30 V

CHESTER-X5