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How to Play LRTF Games

by Rob Mitchell

1. How to play "LRTF" Vectrex games.

What does "LRTF" mean? Well, that's my mnemonic for "Left, Right, Thrust, & Fire." What are "LRTF" games? These games use controller buttons 1, 2, 3, & 4, for Left, Right, Thrust, & Fire, instead of or in addition to the joystick. The reason that the programmers use the buttons is to give the gameplay an arcade feel.


2. List of "LRTF" Games:

These currently include: Ripoff, Star Castle, Omega Chase Deluxe, Rockaroids Remix: 3rd Rock, Repulse, & Armor Attack (ver. 2 & 3).

A special case is Birds of Prey which is "LRSF" ... button 3 activates the shields.

Variations Of this theme include: Vector Vaders Version 1 & More Invaders. These are "LR_F" (The "_" means that controller button 3 does nothing.)

Rockaroids Version 1 does thing a little Differently: "LRFT"

Still different LRF_: Abyss & Vector Vaders Remix

And although the game, Moon Lander, uses buttons 1, 2, & 4 for L, R & thrust, the analog joystick is required for small amounts of thrust.


3. How to make "LRTF" Games!

This is the next question: Can control can be changed to make several Vectrex games, like Minestorm, into "LRTF" games?

These include: Minestorm, Space Wars, Bedlam, Solar Quest, all with loss of a particular feature if played with only four buttons. But if you build a custom controller with more than four buttons, then you can accommodate all the features that these games have.

These games use the analog joystick for Left & Right ... all that is needed is to build the horizontal part of a Digital -> Analog circuit to accomodate two buttons and you would have true "LRTF" control of the MineStorm ship!


4. What does an "LRTF" controller look like?

My LRTF controller is built into a Radio Shack project box and features the four buttons "1234" as well as a controller port for plugging in additional Vectrex controllers. Also I am incorporating two switches to make buttons 1 & 2 to work for Left & Right for games like Minestorm.


5. How may an Atari stick be used for playing "LRTF" games:

The standard Atari Stick can be made to work well with these "LRTF" games ... here are several ways:

A. Plug an Atari Stick (or compatible) into the Vectrex and hold by turning it 90 degrees to the left ... Now up is thrust, and Left/Right turns the ship. But pushing the fire button does not work. Instead you pull back on the stick to fire! Kinda weird! Instead you can use an Autofire circuit for firing the missiles. Note that Hyperspace does not work in Rockaroids. Also an ordinary Atari 2600 controller can be modified by easily switching the various colored wires. Then you have a dedicated "LRTF" joystick!

B. Build a serial adapter to interface the Atari 2600 joystick for "LRTF" control. Radio Shack item #26-264 will give you all the components: casing, wiring and the Male/ Female DB9 connectors. Then make the following connnections:

Atari Pin to Vectrex Pin
---------    -----------
Fire 6       Fire 4
Up 1         Thrust 3
Right 4      Right 2
Left 3       Left 1
GND 8        GND 8

Unfortunately, neither of the above allows for hyperspace in Rockaroids which is activated through the analog joystick. But those who are ambitious can build part of Jay Tilton's Digital->Analog circuit into this adapter to gain hyperspace. All you need is the part of the circuit that works for the stick being pushed down and a larger housing for the additional circuit. With this custom adapter, you can now play Rockaroids as you do 2600 Asteroids! Push Up for thrust and back for hyeprspace!

Thanks to Larry Dworsky for his input.

Rob Mitchell, Atlanta, GA



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