ESP-KVM Turns an ESP32-P4 Board Into a $45 IP KVM

Out-of-Band Management for the Price of a Nice Lunch

ESP-KVM is an open-source IP KVM built around the ESP32-P4, and the bill of materials is the headline. A Waveshare ESP32-P4-ETH board runs about $20, a Geekworm C790 MIPI CSI-to-HDMI adapter about $24, and an optional PC817 optocoupler module for power and reset control adds roughly $1.30. Total: approximately $45 for remote keyboard, video, and mouse access to a machine that has no other way of asking for help.

• ~$45 total BoM: Waveshare ESP32-P4-ETH (~$20), Geekworm C790 CSI-to-HDMI adapter (~$24), optional PC817 optocoupler (~$1.30)
• 20 fps with MJPEG encoding, 7 fps with H.264, plus resolution change handling
• Full input support: keyboard, absolute and relative pointer, media keys, copy/paste, and a touch mode for phones and tablets
• Multiple viewers with takeover, HTTPS login, virtual media, ATX power control, Wake-on-LAN, and firmware updates with rollback

Why an IP KVM Is the Homelab Tool You Skip Until You Need It

Everything is fine until it isn't. A BIOS setting needs changing, a boot drive fails to enumerate, a kernel update leaves a machine sitting at an initramfs prompt — and none of these are reachable over SSH, because SSH requires the thing that is broken. The commercial answer costs several hundred dollars per machine, which is why most home labs have exactly zero of them and a monitor on a cart instead.

At $45 the arithmetic changes. That is close to the point where you fit one per machine rather than sharing one, and a KVM you do not have to physically move is a categorically more useful device than one you do.

What Does the ESP32-P4 Bring to This?

The MIPI CSI interface, mostly. Capturing HDMI output requires converting it to something the microcontroller can ingest, and the C790 adapter handles that hand-off into the P4's camera interface. From there the P4's clock speed and memory are enough to encode a usable stream — 20 fps in MJPEG, or 7 fps if you want H.264's smaller bandwidth footprint.

MJPEG at 20 fps is the right default for this job. It is not smooth enough for video, but a BIOS menu and a boot log are largely static images with occasional changes, which is exactly the workload MJPEG handles gracefully and with minimal latency. The feature list runs well past bare video too: virtual media for mounting an ISO remotely, ATX power control through the optocoupler, Wake-on-LAN, and firmware updates with rollback — the last of which is a thoughtful touch on a device whose entire job is being reachable when nothing else is.

Should You Put This on the Open Internet?

No, and the project says so directly. The security evaluation is incomplete, and the recommendation is to keep it on a LAN or behind a VPN. HDMI audio is also not implemented yet.

That is the honest framing for a project at this stage, and it is worth respecting rather than working around. An IP KVM is by definition a device with total control over a machine — keyboard input, power, and boot media. The threat model for exposing one publicly is unforgiving even when the firmware has been through a formal review, which this has not. Put it on a management VLAN and reach it the way you reach anything else sensitive.

Part of a Good Run for the ESP32-P4

The P4 keeps showing up in projects that would have needed a small Linux machine a couple of years ago. Just yesterday our mini computer coverage looked at a text-mode web browser running on an ESP32, and the Waveshare RP2350 PoE board covers similar networked-microcontroller ground from a different direction.

Everything for ESP-KVM is published — the project lives at espkvm.io with source on GitHub and a live demo you can try before buying anything. For a weekend build that permanently removes a recurring annoyance from your rack, this is about as good a return as $45 gets.

Sources: CNX Software — July 30, 2026; Hackaday — July 30, 2026.