Tangible Lunar Landar Controller

Jan 30, 2018 20:28 · 936 words · 5 minutes read Interaction Fabrication

Design and Sketching Concepts

For this assignment, I tried about both versions of the game. According to the instructions, we were supposed to make the controller work for both games.

First, I sketched out the current controls for each game:

Then I came up with an initial design:

This had a joystick on the left that would go only left and right, and a joystick on the right that would go up and down. A toggle switch in the middle would change if the game mode is Atari or the other one. Depending on what the toggle was set to, the joysticks would either trigger w a s d or up down left right on the keyboard, since each game used a different set of keys.A joystick in the top middle and a button would act as a mouse click. A trigger on the top right would act as the spacebar.

After experimenting with the Atari game, I realized that it also worked with the arrow keys, even though not documented. Therefore I could trigger the same keys no matter the game, so the toggle switch is no longer needed to switch between game modes.

I redesigned without that middle button:

I also experimented with adding the space bar on the top of the controller, as this would be easier to build:

Then I thought a bit - users are not accustomed to using joysticks that just go in a single axis. They are much more used to working with buttons. So I should make a controller just with that. Also I discovered there are joysticks you can also press down to click. This would allow both the joystick and button on my controller for the mouse to be combined into that single joystick that can be clicked:

I would etch or draw on the conroller symbols showing what the buttons do.

After emailing back and forth with Tom Igoe (the instructor), I learned that we only needed to design for one of the games, and only needd to make controls for a specific game. In this case, for the “other” version (not the Atari one), the only controls are really left, right, up for the gas, and click to start. This would let me do a controller with just those 4 controls:

Using a joystick to allow for adjustable thruster

When playing the game, I found it annoying that the thruster could only be fully on or off. This made it more challenging to ease into a smooth the landing. I thought the ideal situation would be to be able to control how strong the thrust is with a sort of joystick or slide mechanism, similar to how it is controlled in airplanes or fighter jets.

I experimented with doing this by pressing rapidly on the up key; this got the desired result of the thrusters only emitting part of their capacity. I realized we could simulate this by having the controller repeatedly press the up key, and how far the joystick or slide potentiometer is pushed would correspond to how long the up key is pressed down for in each period.

This methodology corresponds directly to how Pulse With Modulation works, where a signal is on for a specific period in an interval:

Source: https://www.arduino.cc/en/Tutorial/PWM

Source: https://www.arduino.cc/en/Tutorial/PWM

For the game, we could model the tapping of the up key just like this.

For the physical control, I did not have a slide potentiometer; I only had a joystick that could move in both axises. Allowing the user to move the joystick in both the x and y would be confusing, as the x is never used, and only one direction of the y is used.

A clearer interface would be one where they can only pull the y in one direction and that would control the strenght of the thruster. To try making this, I cut a thin slot into a piece of card-paper, and removing the knob from on top of the joystick:

I then use a button I had from a switch I removed off of a Korg mixer as this button would indicate it should be pushed in a single direction:

Assembling and Coding the Controller

When it came time to assemble, I laid everything out similar to the sketch, except with the joystick on the right:

I originally attempted to have the joystick attached via pins to a small breadboard:

However, this proved unreliable, as the joystick would easily be pushed up or down, and could become slightly displaced for a moment from the breadboard, providing inconsistent resistance rating. This caused me hours of troubleshooting and pain.

I ended up soldering wires to the pins on the joystick; this proved much more reliable:

I wrote code for the controller to achieve the pulse with modulation effect on the thrust key. To calibrate the 0 on the joystick, when the start key is pressed, the joystick y is zeroed.

Testing it Out

I tested out the controls and they worked well. Being able to have light thrusters instead of full strength let me get a smooth landing:

Assembling the Final Case

To assemble the final case, I drew some guides on a piece of black card-paper and cut them with an exacto knife.

To get precise folds I cut light lines into one of the sides.

To create a secure folding I used a glue gun. I had the bottom close via a slot so that the case can be opened in case anything goes wrong.

The fully assembled case
The controller felt great to hold and fun to play the game with