Unlock the Future!
With the Robo Technology Set

Build and program your own robots with this classic 2003 set! A nostalgic trip for Mindstorms fans and a unique addition to any LEGO collection.

🏛 RCX
Set #9785

Robo Technology Set (Serial Cable)

The Robo Technology Set (Serial Cable) is a fascinating glimpse into LEGO's early forays into robotics.

🏆 Best For: Enthusiasts interested in LEGO robotics and programming, educators looking for hands-on learning tools ⏱ 4.5 hr build 🧩 221 pcs
★★★☆☆ 3.8

Fans appreciate this set as a foundational introduction to LEGO robotics, but some find the programming interface outdated and the building experience simple. The limited sensor options compared to newer Mindstorms sets are a common criticism.

📝 Our Take

The Robo Technology Set (Serial Cable) is a fascinating glimpse into LEGO's early forays into robotics. Released in 2003, this set provides the fundamental building blocks for creating programmable robots using the RCX brick and Technic parts. It's a great way to explore the intersection of LEGO and computer programming.

This set is perfect for LEGO enthusiasts interested in robotics and programming. The building experience is relatively straightforward, focusing on functionality over complex aesthetics. It's a fantastic educational tool for introducing basic robotics concepts.

Skip this if you're looking for visually stunning display models or advanced building techniques. This set prioritizes functionality and programming over intricate design. Consider more recent LEGO Mindstorms sets for more advanced robotics features and a wider range of sensors.

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🧱 Building Experience

🧩
221
Pieces
4.5h
Build Time
📊
Intermediate
Difficulty
Build Highlights:
  • Learning the basics of programming LEGO robots
  • Understanding gear ratios and mechanical movements
  • Experimenting with sensors and motor control
  • Creating custom robot programs

📈 Investment Analysis

→ Price stable
B
Investment Grade
⏳ Active
The Robo Technology Set (Serial Cable) holds moderate investment potential. As an early Mindstorms-adjacent set, it appeals to collectors interested in the history of LEGO robotics. The relatively low piece count and specialized nature of the RCX system limit its mass appeal, but its rarity and historical significance could drive value over time. Keeping the set complete with the serial cable and software is crucial for maximizing its investment potential. The condition of the RCX brick is also a key factor.

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

Compare Similar Sets

The Robo Technology Set (Serial Cable) is a foundational set in LEGO robotics, but it lacks the advanced sensors and capabilities of modern Mindstorms sets. While newer sets like the LEGO MINDSTORMS Robot Inventor (51515-1) offer more sophisticated programming and building options, this set provides a unique historical perspective on LEGO robotics. Collectors interested in the evolution of LEGO technology may prefer this set, while those seeking advanced functionality should opt for newer Mindstorms offerings.

📦 Full Parts Inventory - 67 unique parts • 221 total pieces

Plate Round 2 x 2 with Rounded Bottom [Boat Stud] Plate Round 2 x 2...
Part #: 2654 Black
Technic Pin with Friction Ridges Lengthwise and Center Slots Technic Pin with ...
Part #: 2780 12× Black
Technic Wedge Belt Wheel Tire Technic Wedge Bel...
Part #: 2815 Black
Tyre 81.6 x 15 Motorcycle Tyre 81.6 x 15 Mo...
Part #: 2902 Black
Wheel 61.6 x 13.6 Motorcycle Wheel 61.6 x 13.6...
Part #: 2903 White
Sensor, Light with Fixed Cable Sensor, Light wit...
Part #: 2982c01 Blue
Brick 2 x 4 Brick 2 x 4
Part #: 3001 Red
Brick 2 x 2 Brick 2 x 2
Part #: 3003 Yellow
Dome Hemisphere 4 x 4 Multifaceted Dome Hemisphere 4...
Part #: 30208 Trans-Neon Green
Plate 1 x 2 Plate 1 x 2
Part #: 3023 Blue
Plate 6 x 12 Plate 6 x 12
Part #: 3028 Red
Technic Plate 2 x 6 [5 Holes] Technic Plate 2 x...
Part #: 32001 Blue
Technic Pin 3/4 Technic Pin 3/4
Part #: 32002 Dark Gray
Technic Axle Connector with Axle Hole Technic Axle Conn...
Part #: 32039 Light Gray
Technic Axle 2 Notched Technic Axle 2 No...
Part #: 32062 Black
Technic Brick 1 x 2 with Axle Hole Type 2 [X Opening] Technic Brick 1 x...
Part #: 32064b Green
Technic Axle 5 Technic Axle 5
Part #: 32073 Light Gray
Technic Bush 1/2 Smooth with Axle Hole Reduced Technic Bush 1/2 ...
Part #: 32123a Light Gray
Technic Beam 3 x 5 L-Shape with Quarter Ellipse Thin Technic Beam 3 x ...
Part #: 32250 Blue
Plate 1 x 8 Plate 1 x 8
Part #: 3460 Blue
Wheel with Split Axle hole Wheel with Split ...
Part #: 3482 Yellow
Tyre Offset Tread 24 x 8 Tyre Offset Tread...
Part #: 3483 Black
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 Red
Technic Gear 40 Tooth Technic Gear 40 T...
Part #: 3649 Green
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 16 [15 Pin Holes] Technic Brick 1 x...
Part #: 3703 Blue
Technic Brick 1 x 16 [15 Pin Holes] Technic Brick 1 x...
Part #: 3703 Black
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 Yellow
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 Yellow
Technic Axle Pin without Friction Ridges Lengthwise Technic Axle Pin ...
Part #: 3749 Tan
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
Hair, Smooth Hair, Smooth
Part #: 3901 Brown
Bracket 2 x 2 - 2 x 2 Bracket 2 x 2 - 2...
Part #: 3956 Blue
Technic Wedge Belt Wheel [aka Pulley] Technic Wedge Bel...
Part #: 4185 Yellow
Technic Pin 1/2 Technic Pin 1/2
Part #: 4274 Light Gray
Technic Axle 3 Technic Axle 3
Part #: 4519 Light Gray
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
Light Brick 1 x 2 with Single Side Light Light Brick 1 x 2...
Part #: 6035 White
Hair Ponytail Hair Ponytail
Part #: 6093 Black
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 Axle 1.5 with Perpendicular Axle Connector (Technic Pole Reverser Handle) Technic Axle 1.5 ...
Part #: 6553 Light Gray
Technic Axle 3 with Stud Technic Axle 3 wi...
Part #: 6587 Dark Gray
Motor, 9V Mini [Old Style] Motor, 9V Mini [O...
Part #: 71427c01 Light Gray
Cable, Serial, for IR Transmitter Tower Cable, Serial, fo...
Part #: 71793 Light Gray
Transmitter Tower, IR, Serial with Black Front Transmitter Tower...
Part #: 76091 Dark Gray
Hose, Ribbed 7mm D. 12L / 9.6cm Hose, Ribbed 7mm ...
Part #: 78c12 Purple
Technic Rubber Belt Medium [24mm ID] [Round Cross Section] Technic Rubber Be...
Part #: 85544 Blue
Sensor, Touch Sensor, Touch
Part #: 879 Light Gray
Hub, RCX 2.0, No Power Jack [Complete Assembly] Hub, RCX 2.0, No ...
Part #: 884c Yellow
Hips and Blue Legs Hips and Blue Legs
Part #: 970c28 Blue
Torso, White Arms, Yellow Hands [Plain] Torso, White Arms...
Part #: 973c27h01 White
🧱 LEGO Test Mat for...
Part #: 45533 [No Color/Any Color]
🧱 Storage Bin Lid, ...
Part #: 71082 Trans-Clear
🧱 Storage Bin, Dact...
Part #: upn0038 Bright Green
This set features a variety of Technic pins and bushings useful for building functional models. The abundance of Light Gray Technic Bushes and Black Technic Pins makes it a good source for basic Technic elements.

💎 Notable Parts

Light Gray Technic Bush (20x) $1.00
Black Technic Pin with Friction Ridges Lengthwise and Center Slots (12x) $0.60
Light Gray Technic Pin without Friction Ridges Lengthwise (12x) $0.60
Yellow Wheel with Split Axle hole (4x) $0.80
Est. BrickLink Part Value
$3.00

💡 MOC Potential

🤖 Custom robots with unique functionalities
🚗 Programmable rovers and automated vehicles
🏛 Automated displays and interactive models

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Charts Inventory Statistics

67
Unique Parts
221
Total Pieces
0
Minifigures
Inventory Version: 1