v1.0.0 is 2.0 release
v1.1.0 is 2.1 release

Place next to radar or roboport to scan their vision ranges for entities, ghost entities, tiles or modules.
Can scan all or just select objects and can be used to detect enemies, players, fish, ores and all sorts of things.

Flexible combinator capable of detecting almost all objects in the game in real time.
Essentially just calls find_entities_filtered/count_entities_filtered and converts the result into circuit signals.
Customizable update rate.

Configure in first combinator section, results appear in second.

Options:

• Signal-E scans for all entities, otherwise configure select entities, which can include machines, enemies, trees, rocks, etc.
• Item-on-ground can return the number of items on the ground.
• Signal-M scans for modules inside any machine that was also scanned.
• Signal-Skull filters entities to just hostile ones (E+Skull to detect any enemy)

• Select tiles like concrete can be scanned too.

• Ghost mode: When the Entity-ghost signal is specified, all or select ghost entities are returned (possibly to detect and deliver missing buildings to a planet)

• Signal-C: Return only the total count and not individual entity counts, this can be a lot more UPS efficient.

• Left-Right or Up-Down arrows: restrict scanned area to less than the total vision range of the radar/roboport.

Performance:

Update frequency can be adjusted in settings, default to 20 ticks.
Generally find_entities_filtered can be pretty fast, but large entity counts are slow to iterate in lua, use Signal-C if many entities or tiles need to be scanned but only the total is needed.
Restricting the scanned area may help.

This mod was thrown together pretty quickly since I couldn't find one that did everything I wanted.
Let me know of any issues or suggestions!