Unlock the Future!
Build Your Own Robotics Revolution

Go back to 1999 and rediscover the original LEGO Mindstorms RCX with 390 pieces. Perfect for vintage LEGO collectors and robotics enthusiasts.

🏛 RCX
Set #9735

Robotics Discovery Set

The Robotics Discovery Set is a pioneering introduction to LEGO robotics.

🏆 Best For: Perfect for teens and adults interested in robotics and programming ⏱ 4.5 hr build 🧩 390 pcs
★★★★☆ 4.0

Fans appreciate this set as a nostalgic introduction to LEGO robotics, praising its educational value and hands-on learning experience. Criticisms focus on the outdated technology compared to newer LEGO robotics systems.

📝 Our Take

The Robotics Discovery Set is a pioneering introduction to LEGO robotics. Released in 1999 as part of the RCX (Robotics Command System) line, it allows builders to create programmable robots using LEGO Technic elements, fostering an early interest in STEM fields.

This set is perfect for young builders and educators looking to explore robotics. With a manageable piece count and intuitive programming interface (for its time), it provides a hands-on learning experience suitable for classroom environments or home projects.

Skip this if you're seeking cutting-edge robotics features. Modern LEGO Mindstorms or Spike Prime sets offer more advanced sensors, motors, and programming capabilities.

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Try asking:
What are the key features of the RCX brick in this set? How does this set compare to modern LEGO Mindstorms sets? What are some creative ways to use the included sensors and motors? What is the best way to store and maintain the RCX brick for long-term use?

🧱 Building Experience

🧩
390
Pieces
4.5h
Build Time
📊
Intermediate
Difficulty
Build Highlights:
  • Introduction to basic robotics concepts
  • Programming the RCX brick
  • Experimenting with sensors and motors
  • Building functional robots with Technic elements

📈 Investment Analysis

→ Price stable
B
Investment Grade
⏳ Active
The Robotics Discovery Set (9735-1) presents a moderate investment opportunity. As a vintage set from the early days of LEGO robotics, it holds nostalgic appeal for collectors and enthusiasts interested in the history of LEGO's programmable systems. The presence of the RCX brick, a key component in early LEGO robotics, contributes to its collectibility. However, the set's value is somewhat limited by the availability of newer, more advanced robotics sets. While it may appreciate modestly over time, its investment potential is not as high as some other limited-edition or licensed LEGO sets. Condition and completeness are critical factors in determining its value.

Not Financial Advice: Content is for educational purposes only. Past performance doesn't guarantee future results. Full disclaimer

Compare Similar Sets

The Robotics Discovery Set offers a glimpse into the early days of LEGO robotics, but modern sets like LEGO Mindstorms 51515-1 offer vastly superior capabilities. This older set is for collectors interested in the evolution of LEGO robotics, while newer sets are for those seeking cutting-edge functionality.

📦 Full Parts Inventory - 106 unique parts • 391 total pieces

Tile 1 x 4 with Groove Tile 1 x 4 with G...
Part #: 2431 Light Gray
Wedge Plate 3 x 3 Cut Corner Wedge Plate 3 x 3...
Part #: 2450 Green
Brick 2 x 6 Brick 2 x 6
Part #: 2456 Blue
Tile Special 1 x 1 with Clip and Straight Tips Tile Special 1 x ...
Part #: 2555 Black
Brick Round Corner 4 x 4 Full Brick Brick Round Corne...
Part #: 2577 Blue
Plate Round 2 x 2 with Rounded Bottom [Boat Stud] Plate Round 2 x 2...
Part #: 2654 Black
Technic Brick 1 x 10 [9 Pin Holes] Technic Brick 1 x...
Part #: 2730 Blue
Technic Pin with Friction Ridges Lengthwise and Center Slots Technic Pin with ...
Part #: 2780 13× Black
Technic Beam 1 x 4 Thin with Stud Connector Technic Beam 1 x ...
Part #: 2825 Light Gray
Technic Engine Crankshaft Center Technic Engine Cr...
Part #: 2854 Light Gray
Brick 2 x 4 Brick 2 x 4
Part #: 3001 10× Blue
Brick 2 x 2 Brick 2 x 2
Part #: 3003 Blue
Brick 1 x 2 Brick 1 x 2
Part #: 3004 16× Blue
Dome Hemisphere 4 x 4 Multifaceted Dome Hemisphere 4...
Part #: 30208 Trans-Neon Green
Plate Special 1 x 2 with 4 x 4 disk at 90 degrees Plate Special 1 x...
Part #: 30209 Blue
Plate 2 x 2 Plate 2 x 2
Part #: 3022 Light Gray
Plate 1 x 2 Plate 1 x 2
Part #: 3023 14× Light Gray
Wing Insectoid Large with Arm Hinge and Circuitry Print Left (Print on Top, Tip on Left, Logo at Back Edge) Wing Insectoid La...
Part #: 30230pr0001 Trans-Dark Blue
Wing Insectoid Large with Arm Hinge and Circuitry Print Right (Print on Top, Tip on Right, Logo at Back Edge) Wing Insectoid La...
Part #: 30230pr0002 Trans-Dark Blue
Plate 6 x 10 Plate 6 x 10
Part #: 3033 Light Gray
Slope 45° 2 x 1 with Bottom Pin Slope 45° 2 x 1 w...
Part #: 3040b Light Gray
Tile 2 x 2 with Groove Tile 2 x 2 with G...
Part #: 3068b Dark Turquoise
Tile 1 x 2 with Groove Tile 1 x 2 with G...
Part #: 3069b Light Gray
Technic Brick 1 x 2 [2 Pin Holes] Technic Brick 1 x...
Part #: 32000 Light Gray
Technic Plate 2 x 6 [5 Holes] Technic Plate 2 x...
Part #: 32001 Light Gray
Technic Pin 3/4 Technic Pin 3/4
Part #: 32002 Dark Gray
Technic Beam 1 x 11.5 Double Bent Thick Technic Beam 1 x ...
Part #: 32009 Purple
Technic Axle and Pin Connector Angled #1 Technic Axle and ...
Part #: 32013 Blue
Technic Axle and Pin Connector Angled #6 - 90° Technic Axle and ...
Part #: 32014 Blue
Technic Axle and Pin Connector Angled #5 - 112.5° Technic Axle and ...
Part #: 32015 Light Gray
Technic Axle and Pin Connector Angled #3 - 157.5° Technic Axle and ...
Part #: 32016 Blue
Technic Beam 1 x 5 Thin Technic Beam 1 x ...
Part #: 32017 Light Gray
Plate Special 1 x 2 with Door Rail Plate Special 1 x...
Part #: 32028 Light Gray
Technic Axle Connector with Axle Hole Technic Axle Conn...
Part #: 32039 Light Gray
Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [3 Lateral Holes, Big Pin Hole] Technic Pin Long ...
Part #: 32054 Dark Turquoise
Technic Axle 2 Notched Technic Axle 2 No...
Part #: 32062 Black
Technic Brick 1 x 2 with Axle Hole Type 1 [+ Opening] and Bottom Pin Technic Brick 1 x...
Part #: 32064a Dark Turquoise
Technic Axle 5 Technic Axle 5
Part #: 32073 Black
Launcher, Technic Competition Cannon, Round Bottom with Same Color Ends Launcher, Technic...
Part #: 32074c01 Dark Turquoise
Launcher, Technic Competition Cannon, Round Bottom with Black Ends Launcher, Technic...
Part #: 32074c02 Dark Turquoise
Hub, Scout Brick [Complete Assembly] Hub, Scout Brick ...
Part #: 32104c01 Blue
Technic Bush 1/2 Smooth with Axle Hole Reduced Technic Bush 1/2 ...
Part #: 32123a Light Gray
Plate 1 x 8 Plate 1 x 8
Part #: 3460 Light Gray
Wheel with Split Axle hole Wheel with Split ...
Part #: 3482 Dark Turquoise
Plate 1 x 3 Plate 1 x 3
Part #: 3623 Light Gray
Tyre 43 x 17 Tyre 43 x 17
Part #: 3634 Black
Technic Gear 8 Tooth Technic Gear 8 Tooth
Part #: 3647 Light Gray
Technic Gear 24 Tooth [New Style with Single Axle Hole] Technic Gear 24 T...
Part #: 3648b Light Gray
Technic Gear 40 Tooth Technic Gear 40 T...
Part #: 3649 Light Gray
Technic Gear 24 Tooth Crown with Reinforcements [New Style] Technic Gear 24 T...
Part #: 3650c Light Gray
Plate 1 x 6 Plate 1 x 6
Part #: 3666 Light Gray
Technic Pin without Friction Ridges Lengthwise Technic Pin witho...
Part #: 3673 12× Light Gray
Technic Brick 1 x 2 [1 Pin Hole] Technic Brick 1 x...
Part #: 3700 Blue
Technic Brick 1 x 4 [3 Pin Holes] Technic Brick 1 x...
Part #: 3701 Blue
Technic Brick 1 x 8 [7 Pin Holes] Technic Brick 1 x...
Part #: 3702 Blue
Technic Brick 1 x 16 [15 Pin Holes] Technic Brick 1 x...
Part #: 3703 Blue
Technic Axle 4 Technic Axle 4
Part #: 3705 Black
Technic Axle 6 Technic Axle 6
Part #: 3706 Black
Technic Axle 8 Technic Axle 8
Part #: 3707 Black
Technic Axle 12 Technic Axle 12
Part #: 3708 Black
Technic Plate 2 x 4 [3 Holes] Technic Plate 2 x...
Part #: 3709 Light Gray
Technic Plate 2 x 4 [3 Holes] Technic Plate 2 x...
Part #: 3709 Purple
Plate 1 x 4 Plate 1 x 4
Part #: 3710 Light Gray
Plate 1 x 4 Plate 1 x 4
Part #: 3710 Yellow
Plate 1 x 4 Plate 1 x 4
Part #: 3710 Dark Turquoise
Technic Bush Technic Bush
Part #: 3713 20× Light Gray
Technic Axle 10 Technic Axle 10
Part #: 3737 Black
Technic Plate 2 x 8 [7 Holes] Technic Plate 2 x...
Part #: 3738 Light Gray
Slope Inverted 33° 3 x 2 [Connections between Studs] Slope Inverted 33...
Part #: 3747b Blue
Technic Axle Pin without Friction Ridges Lengthwise Technic Axle Pin ...
Part #: 3749 Light Gray
Plate 2 x 10 Plate 2 x 10
Part #: 3832 Light Gray
Technic Brick 1 x 6 [5 Pin Holes] Technic Brick 1 x...
Part #: 3894 Blue
Technic Brick 1 x 12 [11 Pin Holes] Technic Brick 1 x...
Part #: 3895 Blue
Hinge Brick 1 x 2 Base Hinge Brick 1 x 2...
Part #: 3937 Black
Hinge Brick 1 x 2 Top Plate Thin Hinge Brick 1 x 2...
Part #: 3938 Black
Brick Round 2 x 2 with Axle Hole Brick Round 2 x 2...
Part #: 3941 Blue
Dish 4 x 4 Inverted [Radar] Dish 4 x 4 Invert...
Part #: 3960 White
Technic Gear 16 Tooth with Round Holes [Old Style] Technic Gear 16 T...
Part #: 4019 Light Gray
Plate Round 2 x 2 with Axle Hole Type 1 (+ Opening) Plate Round 2 x 2...
Part #: 4032a White
Tile 1 x 8 with Groove Tile 1 x 8 with G...
Part #: 4162 Light Gray
Technic Pin 1/2 Technic Pin 1/2
Part #: 4274 Light Gray
Slope 33° 3 x 1 Slope 33° 3 x 1
Part #: 4286 Yellow
Plate 1 x 10 Plate 1 x 10
Part #: 4477 Light Gray
Technic Axle 3 Technic Axle 3
Part #: 4519 Black
Dish 2 x 2 Inverted [Radar] Dish 2 x 2 Invert...
Part #: 4740 White
Wire with Brick 2 x 2 x 2/3 Pair, 20L Wire with Brick 2...
Part #: 5306bc020 Black
Wire with Brick 2 x 2 x 2/3 Pair, 36L Wire with Brick 2...
Part #: 5306bc036 Black
Arm Piece with Pin, 2 Fingers Arm Piece with Pi...
Part #: 6048a Black
Plate Round 1 x 1 with Solid Stud Plate Round 1 x 1...
Part #: 6141 Blue
Plate Round 1 x 1 with Solid Stud Plate Round 1 x 1...
Part #: 6141 Light Gray
Technic Axle and Pin Connector Perpendicular Technic Axle and ...
Part #: 6536 Light Gray
Technic Axle Connector Ridged [with x Hole x Orientation] Technic Axle Conn...
Part #: 6538b Light Gray
Technic Brick 1 x 1 with Pin Hole Technic Brick 1 x...
Part #: 6541 Blue
Technic Axle 1.5 with Perpendicular Axle Connector (Technic Pole Reverser Handle) Technic Axle 1.5 ...
Part #: 6553 Light Gray
Technic Pin Long with Friction Ridges Lengthwise, 2 Center Slots Technic Pin Long ...
Part #: 6558 Black
Technic Cam Technic Cam
Part #: 6575 Light Gray
Tyre 20 x 30 Balloon Medium 49.6 x 20 Tyre 20 x 30 Ball...
Part #: 6581 Black
Wheel 20 x 30 Balloon Medium Wheel 20 x 30 Bal...
Part #: 6582 Dark Turquoise
Technic Axle 3 with Stud Technic Axle 3 wi...
Part #: 6587 Dark Gray
Technic Beam 1 x 9 Bent (6 - 4) Thick Technic Beam 1 x ...
Part #: 6629 Dark Turquoise
Technic Beam 1 x 3 Thin Technic Beam 1 x ...
Part #: 6632 Light Gray
Motor, 9V Mini [Old Style] Motor, 9V Mini [O...
Part #: 71427c01 Light Gray
Rubber Band Small 13mm (Square Cross Section) Rubber Band Small...
Part #: 71509 Black
Ball 41mm Ball 41mm
Part #: 72048 Yellow
Hose Rigid 3mm D. 16L / 12.8cm Hose Rigid 3mm D....
Part #: 75c16 Yellow
Hose Rigid 3mm D. 36L / 28.8cm Hose Rigid 3mm D....
Part #: 75c36 Dark Turquoise
Hose Rigid 3mm D. 44L / 35.2cm Hose Rigid 3mm D....
Part #: 75c44 Yellow
Technic Gear 24 Tooth Clutch with Dark Gray or Light Gray Center Technic Gear 24 T...
Part #: 76019 White
Projectile, Technic Competition Arrow, Beam Shaft with Solid Black Rubber End Projectile, Techn...
Part #: 76110c01 Yellow
Sensor, Touch Sensor, Touch
Part #: 879 Light Gray
The set contains a good selection of Technic parts in light gray and blue, useful for building functional models. While no parts are exceptionally rare, the quantity of Technic pins and bushes is beneficial for MOC builders.

💎 Notable Parts

Blue Technic Brick 1 x 16 [15 Pin Holes] (6x) $0.90
Dark Turquoise Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [3 Lateral Holes, Big Pin Hole] (8x) $2.00
Light Gray Technic Plate 2 x 8 [7 Holes] (6x) $1.20
Blue Brick 2 x 4 (10x) $0.50
Est. BrickLink Part Value
$4.60

💡 MOC Potential

🤖 Advanced automated machines
🚗 Remote-controlled vehicles
🌳 Automated plant watering system

📰 RCX News

Community Insights

Real opinions from Reddit and YouTube

What Reddit Says

No Reddit discussions found for this set.

What YouTubers Say

Based on 4 videos
3.0 /5
Mixed
0% positive
BlockTalk AI

The LEGO Robotics Discovery Set (9735-1) appears in a broader context of LEGO Mindstorms discussions, with most videos being neutral retrospectives. While Unbrickme lists Mindstorms sets in their top 10, RacingBrick reports on the discontinuation of newer Mindstorms sets, indicating a bittersweet nostalgia for the product line's history.

Community Sentiment

Based on 4 YouTube reviews

Reddit

Not enough Reddit data

YouTube

3.0 /5
Mixed
0% positive
0
Positive
4
Mixed
0
Critical
BlockTalk AI Analysis

The LEGO Robotics Discovery Set (9735-1) appears in a broader context of LEGO Mindstorms discussions, with most videos being neutral retrospectives. While Unbrickme lists Mindstorms sets in their top 10, RacingBrick reports on the discontinuation of newer Mindstorms sets, indicating a bittersweet nostalgia for the product line's history.

What the Community Says

4 YouTube reviews
BlockTalk AI Summary

Doug's Devices discusses using older Mindstorms sets with modern computers, highlighting the need for USB IR towers due to serial port limitations. BatteryPoweredBricks offers guides on reconditioning older RCX units, showing continued interest in maintaining and utilizing the older Mindstorms technology.

Community Content: These reviews are from Reddit and YouTube users sharing their personal experiences. Opinions may vary.

Charts Inventory Statistics

106
Unique Parts
391
Total Pieces
0
Minifigures
Inventory Version: 1