flow_ChangeDetector

No written description ships with this node, but the parameter names spell out a fairly specific job: a debounce gate for two arbitrary values. It watches object1 and object2 and only reports BOTH_STABLE = true once both have gone unchanged for at least delay_threshold_seconds. If you're driving a workflow off something that updates in bursts - a watched folder, a live feed, a value that gets touched by more than one upstream node before it's "final" - this is the node that stops you from acting on a half-written state.

How it works

Feed anything into object1 and object2 (both wildcard-typed). On each check, the node compares the current value against what it last saw for that slot; if either one changed, the stability clock resets. Only once both have held steady for delay_threshold_seconds does BOTH_STABLE flip to true. cache_key1 and cache_key2 - plain strings, defaulting to obj1/obj2 - read like namespace keys for the node's internal "last value + timestamp" storage, which matters if you drop more than one flow_ChangeDetector into the same graph: give each instance distinct keys so they don't step on each other's cached state.

Since this behavior isn't documented anywhere in the pack's own README, treat this as the reasonable read of the field names rather than a confirmed spec - worth a quick test with two dummy values before you build real logic on top of it.

Inputs and output

• object1, object2 (required, wildcard) - the two things being watched for stability.
• delay_threshold_seconds (FLOAT, default 10, range 0.1–300) - how long both must hold steady before the gate opens.
• cache_key1, cache_key2 (optional STRING, default obj1/obj2) - namespacing for multiple instances.
• BOTH_STABLE (BOOLEAN, output) - true only when both inputs have been unchanged for the full delay.

Installing it

Search ComfyUI-Apt_Preset in ComfyUI Manager and install, or manually: cd ComfyUI/custom_nodes && git clone https://github.com/cardenluo/ComfyUI-Apt_Preset.git, then restart. The README's dependency step is "double-click install.bat," a Windows-first instruction with no requirements.txt visible elsewhere - on Linux/Mac, open that file to see what it installs and do the equivalent by hand in your ComfyUI venv. This node is pure control logic and doesn't need the pack's heavier optional extras (GGUF, Advanced-ControlNet, nunchaku, downloaded models).

Common issues

Since the actual stability logic isn't documented, the biggest risk is assuming it behaves one way and getting surprised - for instance, whether "changed" means an exact equality check or something looser (which would matter a lot for floating-point or image data). Test it against a value you control before wiring it into anything time-sensitive.

If you use more than one flow_ChangeDetector in the same graph, set distinct cache_key1/cache_key2 values on each - leaving them at the shared defaults across multiple instances risks one detector's cached state bleeding into another's.

And the general pack caveat: this is one node in a large, actively developed package where an import failure anywhere can take the whole pack (including this node) offline. If it's missing after install, check the ComfyUI console log at boot for the real traceback before troubleshooting further.