ReLow60 Firmware v1.9 & ReConf v1.2.0: Bottom-Out Dead Zone to Prevent Missed Inputs on Actuation
Overview
We have updated the ReLow60 L-HE firmware to v1.9 and the configurator ReConf to v1.2.0. This release introduces a single feature — a bottom-out dead zone — that eliminates missed inputs that could occur when bottoming out hard or rocking the stem, and allows users to tune its range to their preference. This improvement was made in response to feedback from product testers.
Background: Why Bottoming Out Causes Missed Inputs
Magnetic switches read key travel via ADC values from Hall-effect sensors and convert them to a distance in the range 0–255. Near the deepest part of the stroke (the bottom), sensor output saturates, and the value changes very little.
Product testers reported that “when a key is pressed hard to the bottom, or when the stem is rocked significantly while held down, the input can momentarily drop out at the moment of bottom-out.” Because sensor output saturates near the bottom, aggressive keypresses that introduce stem wobble (stem rattle) cause the filtered value to fluctuate slightly. Since Rapid Trigger detects a release by sensing a return from the deepest pressed point (the peak), any fluctuation near the bottom that briefly drops below the peak can be misinterpreted as a release, resulting in a missed input.
Based on this feedback, the bottom-out dead zone was developed to ensure stable bottom-out behavior even under aggressive use. Additionally, in the previous version v1.8, the estimated bottom value per switch was raised, making it harder for the distance to reach full actuation (255), which also contributed to increased susceptibility to near-bottom fluctuations.
Solution: A Dead Zone That Treats the End of Travel as “Fully Pressed”
In v1.9, we added a mechanism (bottom-out dead zone) that treats a fixed range at the end of travel as the fully pressed state. Once the distance reaches “255 − dead zone” or greater, the distance is clamped to 255.
- Within the dead zone, the bottom-out state is maintained even if the value fluctuates due to stem wobble, preventing false release detection (missed inputs)
- Only the very end of the stroke is affected; the actuation point and Rapid Trigger behavior in the mid-travel region are completely unchanged
- Setting the value to 0 disables the feature
In physical testing, a very small dead zone (distance value of 5–10, equivalent to approximately 0.03–0.06 mm) consistently eliminated bottom-out missed inputs.
Adjustable in ReConf (v1.2.0)
Because the optimal dead zone value varies by preference and switch, a slider has been added to the Calibration screen in ReConf.
- The default value is 10 (a conservative setting that works well in most environments out of the box)
- If missed inputs at bottom-out persist, increase the value; if you want Rapid Trigger to remain active deeper into the bottom-out range, decrease it (or set it to 0)
- This setting applies globally across all profiles
ReLow Series Keyboard Configurator
Settings are preserved across updates. Flashing firmware v1.9 will not affect existing keymap, actuation point, Rapid Trigger, or other configurations.
How to Update
Flashing can be done entirely from the browser using ReConf’s firmware update feature (Web DFU). The procedure is described in a separate article.
How to flash firmware from the browser via ReConf
Source Code (GPL-3.0)
The ReLow60 firmware is based on libhmk (GPL-3.0), and the corresponding source is publicly available.
ReLow60 L-HE Firmware (GPL-3.0)