Raspberry Pi HWMON expands to measure voltages on ARM

Published on May 29, 2026 | Translated from Spanish

The HWMON hardware monitoring driver for Raspberry Pi receives a significant update. A new patch submitted to the hwmon-next branch enables exposing core voltage and SDRAM voltage measurements on single-core ARM boards. The board's firmware provides these readings, which are now propagated to the Linux userspace via standard sysfs interfaces, facilitating access to accurate system data.

Raspberry Pi single-board computer with exposed circuitry, multimeter probes touching test points on the board while a monitor displays Linux terminal showing voltage readings from hwmon sysfs interface, data lines flowing from CPU core and SDRAM modules towards the display, technical engineering visualization, photorealistic render, macro lens focus on board components, green PCB traces glowing faintly, oscilloscope waveform overlay on the screen, metallic heatsink fins visible, dramatic side lighting emphasizing component shadows, ultra-detailed solder joints and pin headers

Technical details of the hwmon-next patch 🛠️

The patch adds support for reading core voltage (vcore) and multiple SDRAM voltages directly from the Raspberry Pi firmware. These measurements are integrated into the Linux kernel's HWMON subsystem, allowing applications and scripts to access them through standard sysfs files. This eliminates the need for external tools or manual firmware queries. The driver can now present data such as vcore, sdram_v, sdram_i, and sdram_p, offering more comprehensive monitoring for developers and enthusiasts.

From the raspberry to the digital voltmeter 🔌

Now you'll be able to know if your Raspberry Pi is getting enough juice, or if, like a teenager, it falls asleep mid-task due to lack of voltage. With this data, you'll know exactly when to scold that generic power supply you bought at a flea market. Of course, don't expect the board to return the favor by measuring your blood pressure when you see the values.