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Environmental Multi-Sensor Device Runs on RPi CM4

Written by Eric Brown

Sfera Labs has launched a $276 “Exo Sense Pi” multi-sensor computer based on an RPi CM4 with sensors for air quality, temp, humidity, light, and motion plus RS-485, an open collector output, 2x digital inputs, a mic, and an RTC.

In 2019, Sfera Labs launched an Exo Sense Py environmental monitoring system that runs MicroPython on an ESP32. Now, the company, which is known for Raspberry Pi Compute Module 3+ (CM3+) based devices such as the Iono Pi Max industrial controller, has launched an Exo Sense Pi that advances to running Raspberry Pi OS Linux on a quad -A72 Raspberry Pi Compute Module 4.

The Exo Sense Pi is designed for residential and commercial applications such as environmental monitoring and data gathering, BLE positioning, indoor people and assets tracking, rooms management and access control, voice control, and more. The device sells for €229 ($276) or €245 ($296) for a model that adds 16GB eMMC.

Exo Sense Pi with PCB half exposed (left) and PCB alone with RPi CM4
(click images to enlarge)

Both standard SKUs ship with 2GB RAM and built-in 802.11 b/g/n/ac with Bluetooth 5.0 BLE via the CM4 module. Special order options include up to 8GB RAM and 32GB eMMC, and the product page language suggests you may be able to buy a barebones model and add your own CM4, including Lite (no eMMC) models.

Like the Exo Sense Py, the Exo Sense Pi (make up your own pronunciation I guess?) is equipped with 2x dual-purpose pins that can each either serve as digital inputs or as TTL level I/Os that support 1-Wire, I2C, and Wiegand. It also similarly provides an open collector output and an RS-485 interface with electrostatic discharge protection.

Other common features include air quality, temperature, humidity, and light intensity sensors, as well as an LED and a piezo buzzer. Like the Py, the Pi is deployed as an 80 x 80mm wall mount ABS case with a fast snap-in terminal block.

New features on the Exo Sense Pi include a microSD slot, a micro-USB port, a pair of PCB temperature sensors, and a motion Microchip ATECC608A secure element chip. The Exo Sense Pi lacks the pressure sensor of the Py model, but in place of the “sound intensity” sensor there is a microphone that can also perform audio recording and processing.

Standard features that were optional on the Py include an RTC with battery and a PIR motion sensor. The Exo Sense Pi lacks the multiple, optional wireless radios of the Py, such as LTE-M, NB-IoT, LoRa, or SigFox.

As before, an earthquake sensor is optional, and the user manual also lists an optional 10/100 Ethernet port with PoE. The EENews Embedded Europe story that alerted us to the launch states: “Other sensors can be added on a separate board such as a carbon dioxide sensor or time of flight sensor without having to redesign the whole system.” It is unclear how such add-ons would be implemented, but the RPi CM4 does have a handy PCIe interface at the ready.

The Exo Sense Pi has a 10-28V DC input with reverse polarity and surge protection. Various ESD and other electromagnetic immunity compliances are listed. The IP20-protected system weighs 90 grams, including the CM4, and has a 0 to 50°C range with 5% to 90% non-condensing relative humidity tolerance.

 Further information

The Exo Sense Pi is available for €229 ($276) or €245 ($296) for a model that adds 16GB eMMC. Volume pricing discounts are also available. More information may be found on Sfera Labs’ Exo Sense Pi shopping/product page.

This article originally appeared on on May 12, 2021

Sfera Labs |

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Environmental Multi-Sensor Device Runs on RPi CM4

by Eric Brown time to read: 2 min