Rev 2 hardware is in fabrication. Here’s where things stand.
Background
The Rejuv is a handheld red and near-infrared light therapy device designed around a specific principle: that delivered dose — measured in J/cm² at the treatment surface — should be known, not estimated. Every unit is individually calibrated using a NIST-traceable optical power meter before it ships, and the companion app uses that calibration record to log and visualize each session.
The current hardware has been running well through internal use and testing. Rev 2 is not a redesign — it’s a targeted set of improvements informed by what the rev 1 measurements revealed.
What’s changing in rev 2
The most significant change is a substitution on the power path PFET — the Mosfet that controls current delivery to the LED channels. The Rev 2 will be moving to a Mosfet with nearly 1/10th the on-resistance of the Rev 1 board. In practical terms, lower on-resistance means less energy is lost as heat in the switching circuit, and more of the available battery power reaches the LEDs as usable optical output.
This matters most in combined mode, where both the red (660 nm) and NIR (805 nm) channels operate simultaneously through the shared power path. The I²R losses — power dissipated as heat proportional to current squared times resistance — are measurable at operating currents. The PFET substitution is expected to recover approximately 10% of optical output.
To be clear: the rev 1 figures published on the Measured Performance page remain valid for those units. The improvement is specific to rev 2 hardware and will be documented with new calibration records once fabrication is complete and measurements are taken.
Evaluation units
The first evaluator placements are being planned around rev 2 hardware. Rev 1 units exist in sufficient quantity for internal testing but were assembled on hand-modified boards that aren’t representative of a clean production design. The goal is for the first people outside the development process to receive hardware that reflects how the device is actually intended to be built.
If you’re interested in an evaluation unit, the early-access list on the homepage is the right place to register.
App
The iOS companion app is in a stable state. It handles NFC session retrieval, Dynamic Optical Response visualization, and session history with calendar view — all working reliably.
The next planned capability is user-selectable dose targeting. Instead of setting a session duration manually, the user will specify a target dose in J/cm² — a standard unit used in photobiomodulation research to describe the energy delivered per unit area of tissue. The app will then calculate the required session time automatically, using the calibrated irradiance value stored for that specific unit. That’s the intended end state: you set a dose; the device and app tell you how long it should be used for.