Openviro Axe PoE is a rack-mountable, open-source environmental sensor. While many servers and network equipment contain temperature sensors, there are two common issues with relying on them for server room temperature. First, most sensing systems are either internal to the servers and are affected by server components, resulting in inaccurate measurements. Secondly, many can only provide data in 1° C increments. Openviro Axe PoE is designed to capture accurate temperature and humidity readings and provide enough sensor fidelity to make that data actionable.

Utilizing a high-quality Bosch environmental sensor, Openviro Axe PoE can deliver an accuracy of +/- 0.5° C, with a fidelity of 0.01° C. With such an accurate reading, you can see environmental trends develop before they become a problem, preserving both uptime and overall equipment health. And with the optional second sensor, you can capture both intake and exhaust temperatures in a server rack.

Up Your Server Game…on a Budget

How hot is your server room? It’s a simple question that’s shockingly difficult to answer.

Openviro Axe PoE is an SNMP-enabled temperature sensor designed to be. simple and secure to deploy to your network environment and deliver more accurate temperature data than most other solutions on the market today. It’s powered by a Raspberry Pi RP2040 and has a temperature sensor that is accurate out of the box to +/- 0.5° C and has a 0.01° C fidelity, delivering smooth charting to your SNMP monitoring software.

Last summer, we launched a beta unit that we called Project Axe Effect. During the beta, we sold nearly 400 units and received tremendous feedback from users around the world. We also heard from multiple users who were alerted to serious HVAC issues in their server rooms before any hardware damage could occur:

"Axe Effect is a simple, cost-effective standalone system which allows me to put a temp sensor in small network cabinets and server rooms [where] a full Eaton system would never be approved by finance.

This led to me catching an air conditioning failure at an unmanned site containing 6 servers, 4 switches and a firewall, allowing me to load shed and arrange for the unit to be repaired as quickly as possible, reducing downtime and preventing damage to hardware due to heat."

— Openviro (Axe Effect) beta tester

The two most requested features from the Beta model were for us to support Power over Ethernet (PoE), along with adding support for multiple temperature sensors, to allow for monitoring both the hot and cold sides of a server rack.

Temperature graph from an APC monitoring system, polled every 60 seconds over 24 hours.

The same scenario from Openviro, showing its higher sensor accuracy and fidelity.

The Openviro Axe PoE is the result of that feedback. It is a rack-mountable unit and supports a pair of Temperature and Humidity sensors, allowing you to collect accurate intake and exhaust temperatures from your server racks.

Fit for Any Rack

The Axe PoE itself consists of two parts: the main unit (which we’re calling "the brain") and the remote sensor probes. The brain is rack-mountable with an attractive aluminum enclosure.

The Sensor probes are inside 3D-printed enclosures, but the final version will be significantly smaller than you see here. The case itself has a pair of magnets embedded in the base to quickly mount them wherever you need them in a server rack. We’re also planning on adding a single mounting point for a rack screw if you want to install it onto a rack rail or even just screw it into the wall.

The probes are connected to the brain with simple RJ12 6P6C cables. While we include cables in the box, custom-length cables are plentiful and inexpensive if you need specific lengths.

Simple Integrations

As for SNMP, we currently support SNMP v1 and v2c, with SNMP v3 support currently in beta. We’re using the standard Entity Sensor MIB, included in basically every SNMP monitoring package out there. Software like Nagios, Observium, PRTG, CheckMK, Zabbix, and even Home Assistant are all capable of recording data from Openviro, along with logging, graphing and alerting you when there are problems.

But again, what makes Openviro different from other smart devices? Well, we’re making it as dumb as possible on purpose. The device is configured through a direct serial console, so there’s no SSH or web host to secure. It relays data via SNMP, not some proprietary protocol that requires a cloud connection on our servers where we also try and collect your data. This is just a sensor that you configure and manage locally.

Features & Specifications

Openviro Axe PoE

• CPU: Raspberry Pi RP2040 32-bit dual ARM Cortex-M0+ @133 MHz
• Memory: 264 KB SRAM
• Storage: 16 MB flash memory
• Network: LAN8710Ai 10/100 Mb
• I/O Connectivity: 2x RJ12 6P6C for THP Probes
• Power Input:
  5 V USB Type-C
  24-54 V Power over Ethernet (Active Class 1)
  12-48 V DC 5.5 mm barrel jack
• Dimensions: 90 x 28.8 x 82.8mm (3.54 x 1.13 x 3.26 in)

Openviro THP probes

• Bosch BME280 temperature/humidity/pressure sensor
• Operating Range: -40° - +85° C; 0 - 100% relative humidity; 300 - 1100 hPa
• Recommended Temperature Range: 0 - +60C (PETG enclosure)
• Accuracy: +/- 0.5° C; +/-3% relative humidity; +/- 1.7 hPa
• Final dimensions TBD

Comparisons

Support & Documentation

Openviro Axe PoE is open and modifiable, and we want our users to contribute to its usefulness. We’re going to be open-sourcing the firmware, and it will be published on our GitHub repo following the conclusion of the campaign. Meanwhile, if you have questions, concerns, or suggestions, please reach out using the appropriate Ask a Question link below.

Manufacturing Plan

We are currently working with with a local PCB manufacturer for the production run. This means the final product will be made and assembled right here in Oregon. Manufacturing and assembly should take roughly 12-14 weeks, and we hope to ship products to all backers toward the end of Summer 2025. We’ll provide more specific timelines as we get closer to the end of the campaign and have more exact numbers for production.

Fulfillment & Logistics

After our production run is complete, we will package everything up and send it along to Crowd Supply’s fulfillment partner, Mouser Electronics, who will handle distribution to backers worldwide. You can learn more about Crowd Supply’s fulfillment service under Ordering, Paying, and Shipping in their guide.

Risks & Challenges

One of the final hurdles for production is CE and UKCA compliance for sale overseas. We are currently awaiting what we hope is the final spin-up of our PCBs to begin testing. While we are confident the devices will pass, any setback in testing and compliance may require component changes or a board re-spin, and will result in a delay of the final products. While we don’t anticipate this being an issue, we’ll be sure to keep all backers up to date about progress and provide current timelines for production and shipping.