Cybermaster

Cybermaster was mainly sold in Europe and Australia/New Zealand, but was available for a short time in America via the Lego Club magazines. It was aimed at a younger audience as an early attempt of merging computer gaming with robotics and LEGO. The Pbrick shares many, especially software, features with the RCX but differs in appearance and technical specifications: 1 output (plus 2 built-in) and 3 sensors.

- It uses RF (27 MHz R/C band) instead of IR for communication.
- It has two built-in motors with integrated tachometers and speedos.
- It is limited to passive sensors (a simple A/D with internal pull-up resistors).
- The sensors shipped with it are colour coded and have internal resistors in their open state (allowing the Pbrick to sense which sensor is attached to which port).
- It has a fixed firmware (so it cannot be upgraded or replaced).
- It has limited RAM for programs and only one program slot.

Despite its obvious limitation it has a number of edges over its 'big brother', the RCX.

- The RF link has greater range and is omnidirectional.
- The built-in tacho and speed sensors on the internal motors provides the same function as the external rotation sensor to the RCX, but without using up sensor ports.

This makes it very useful for various mobile platforms and performing basic motion/positioning tasks.

It talks the same protocol as the RCX but cannot communicate directly to it (due to IR vs RF) but with a repeater (a computer with 2 serial ports and a simple program) they can be integrated.

Codepilot

Sold as part of the Barcode Truck kit. This unit was the first programmable brick (or Pbrick). It features a single motor, a single touch sensor and a light sensor. It is programmed by setting it to 'learn' and using the light sensor to feed barcoded commands. The command set is very limited. Since barcode is just a series of variances in light, this form of command entry was dubbed VLL (Visual Light Link) and has been used in several later Lego models.

Scout

Lego also released a brick named the Scout, which has 2 sensor ports, 2 motor ports, a built in light sensor, and no PC interface. The Scout can be programmed, but the user usually selects one of a collection of built-in programs. In order to program the Scout, a user must enable "power mode" on it. The Scout can store one program.
The RCX can control the Scout brick using the Send IR Message program block. The RCX does all of the controlling, and therefore can be programmed with the PC, while the Scout acts as a "slave". The Scout brick must have all of its options set to "off".
The Scout is also capable of using VLL to control a Micro Scout.

Micro Scout

The Micro Scout was added as an entry level to Lego robotics. It is a very limited Pbrick with a single light sensor and a single built-in motor. It has seven built-in programs and can be controlled by a Scout, Spybotics or RCX unit using VLL.
The unit was sold as part of the Droid Developer Kit (featuring R2D2) and later the Darkside Developer Kit (featuring an AT-AT Imperial Walker).