5 ms·

If someone could explain how this works to someone who only understands basic circuits, that would be much appreciated. How does it maintain state and draw shap

by ksml 10y ago

If someone could explain how this works to someone who only understands basic circuits, that would be much appreciated. How does it maintain state and draw shapes on the oscilloscope and trigger sounds with such basic components? Amazing!

consp 10y ago
A quick view of the system he uses comparators and function generators to create signals for the x/y/ball/paddles, which in case of the ball hitting the x/y axis limit are equal to the lowest or highest of the x/y axis triangular signal which will signal a 'hit'. But this was looked at in a glance and it is quite a lot more complex and mostly goes beyond mis simple analogue electronic knowledge. See the link on the form post for the schematics and some example readouts of the signals.
BooglyWoo 10y ago
I think these images are called "Lissajous Figures".
- mrob 10y ago
  A Lissajous figure is what you get when both the X and Y positions of the beam (or virtual beam) are controlled by sinusoidal oscillators. This is using the same XY mode on the oscilloscope as used for drawing Lissajous figures but it's not a Lissajous figure itself.
  - TheOtherHobbes 10y ago
    It's more like a custom homebrew analog computer with a few unusual additions. Seriously impressive.
  - cr0sh 10y ago
    Technically (loosely) the way the ball (circle) in the game is a lissajous figure; it uses a scaled sin and cosine signal driving the x and y input of the oscope to create it. It's one of several signals (mainly on the y-side) that are mixed down (done in a similar manner to a simple op-amp backed audio mixer circuit) before being sent to the scope input.
exDM69 10y ago
I'll try my best to explain with my electronics hobby background... It's full of analog circuitry like integrators, comparators, op amps etc (note: it's made from discrete transistors, so you won't find an opamp chip in there). The "state" as you mentioned is maintained as a a voltage. The velocity of the ball is stored as a voltage, and the position is produced by integrating that with an integrator. Collisions are found with a comparator, and connected to the circuitry that maintains the velocity. The output to the oscilloscope is two voltages that control the position of the beam. Analog electronics is one of those dying art forms where the number of people capable of doing things like this is quickly dwindling. It's no longer a viable way of building actual products except for a few special applications. I find it a sad state of affairs that we, the mankind, have learned and developed skills and knowledge that we'll be collectively forgetting less than a century later.
- ue_ 10y ago
  I find it hard to believe that analogue electronics is disappearing. I'm an undergrad ECE student and the largest part of my course is analogue, with work in labs too. Granted, it's not an immensely popular hobby, but many art forms and jobs are necessary but aren't hobbies.
  - cr0sh 10y ago
    If it's RF, or chip-surface level - there's analog in there somewhere. While digital logic is somewhat forgiving, for production level work you do need to have some understanding of analog to make a successful design and stable implementation. Plus there's always the power-supply stuff, and a bunch of other things that will always be analog as well. So I agree that it won't completely die off (especially in the commercial realm) - but it certainly isn't as common in the hobbyist world as it once was. /saying this as someone who considers analog a black though beautiful art
  - moftz 10y ago
    There is plenty of analog work in the RF engineering careers. I mostly do digital but most of my coworkers started out and currently work on analog boards. Although we are moving a lot of our stuff to SDR so the RF board in the product is just getting smaller but needs to be able to handle larger bitrates.
sdk77 10y ago
The oscilloscope works like a vector display (or x-y plotter). A circle can be displayed by feeding a sinewave voltage to the Y input and a cosine to the X input. Adding a voltage to the Y input moves the ball up and down. Similarly, adding a voltage to the X input moves the ball left to right. Increasing the amplitude of both the X and Y signal will enlarge the ball. State is maintained by flip-flops built from discrete transistors (mono-stable multivibrators). Collision detection is just a matter of comparing the X and Y voltage of object A to the X and Y voltage of object B. If the voltage are (almost) the same, both objects are on the same screen position.

by ksml 10y ago

consp 10y ago

A quick view of the system he uses comparators and function generators to create signals for the x/y/ball/paddles, which in case of the ball hitting the x/y axis limit are equal to the lowest or highest of the x/y axis triangular signal which will signal a 'hit'. But this was looked at in a glance and it is quite a lot more complex and mostly goes beyond mis simple analogue electronic knowledge. See the link on the form post for the schematics and some example readouts of the signals.

BooglyWoo 10y ago

I think these images are called "Lissajous Figures".

mrob 10y ago
A Lissajous figure is what you get when both the X and Y positions of the beam (or virtual beam) are controlled by sinusoidal oscillators. This is using the same XY mode on the oscilloscope as used for drawing Lissajous figures but it's not a Lissajous figure itself.
- TheOtherHobbes 10y ago
  It's more like a custom homebrew analog computer with a few unusual additions. Seriously impressive.
- cr0sh 10y ago
  Technically (loosely) the way the ball (circle) in the game is a lissajous figure; it uses a scaled sin and cosine signal driving the x and y input of the oscope to create it. It's one of several signals (mainly on the y-side) that are mixed down (done in a similar manner to a simple op-amp backed audio mixer circuit) before being sent to the scope input.

exDM69 10y ago

I'll try my best to explain with my electronics hobby background... It's full of analog circuitry like integrators, comparators, op amps etc (note: it's made from discrete transistors, so you won't find an opamp chip in there). The "state" as you mentioned is maintained as a a voltage. The velocity of the ball is stored as a voltage, and the position is produced by integrating that with an integrator. Collisions are found with a comparator, and connected to the circuitry that maintains the velocity. The output to the oscilloscope is two voltages that control the position of the beam. Analog electronics is one of those dying art forms where the number of people capable of doing things like this is quickly dwindling. It's no longer a viable way of building actual products except for a few special applications. I find it a sad state of affairs that we, the mankind, have learned and developed skills and knowledge that we'll be collectively forgetting less than a century later.

ue_ 10y ago
I find it hard to believe that analogue electronics is disappearing. I'm an undergrad ECE student and the largest part of my course is analogue, with work in labs too. Granted, it's not an immensely popular hobby, but many art forms and jobs are necessary but aren't hobbies.
- cr0sh 10y ago
  If it's RF, or chip-surface level - there's analog in there somewhere. While digital logic is somewhat forgiving, for production level work you do need to have some understanding of analog to make a successful design and stable implementation. Plus there's always the power-supply stuff, and a bunch of other things that will always be analog as well. So I agree that it won't completely die off (especially in the commercial realm) - but it certainly isn't as common in the hobbyist world as it once was. /saying this as someone who considers analog a black though beautiful art
- moftz 10y ago
  There is plenty of analog work in the RF engineering careers. I mostly do digital but most of my coworkers started out and currently work on analog boards. Although we are moving a lot of our stuff to SDR so the RF board in the product is just getting smaller but needs to be able to handle larger bitrates.

sdk77 10y ago

The oscilloscope works like a vector display (or x-y plotter). A circle can be displayed by feeding a sinewave voltage to the Y input and a cosine to the X input. Adding a voltage to the Y input moves the ball up and down. Similarly, adding a voltage to the X input moves the ball left to right. Increasing the amplitude of both the X and Y signal will enlarge the ball. State is maintained by flip-flops built from discrete transistors (mono-stable multivibrators). Collision detection is just a matter of comparing the X and Y voltage of object A to the X and Y voltage of object B. If the voltage are (almost) the same, both objects are on the same screen position.