LEGO 9747 Robotics Invention System, Version 1.5

Released 1999 · 731 pieces · Mindstorms · RCX

LEGO Robotics Invention System, Version 1.5 (9747) was released in 1999 in the Mindstorms · RCX line, with 731 pieces. That makes it the 4th largest of the 74 Mindstorms sets in the catalog. It was one of 9 Mindstorms sets released that year (see them all). Released in 1999, 27 years ago, well past the two-to-three-year run most LEGO sets get, so it is almost certainly out of production.

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• Estimated value: $173 (modelled from piece count, era, and age, not live market data)

Availability: Likely retired (inferred from its release year, not an official retirement date)

Full details, the price breakdown, and the minifigures included are below. Add it to your collection to track what it's worth.

• The 4th largest of 74 Mindstorms sets
• 24¢ per piece, cheaper per piece than most Mindstorms sets

More from 1999

Set data from the Rebrickable database, refreshed daily. Catalog data as of 2026-09-01. Values are this site's estimates, see how they're calculated.

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