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HOLD Gates, SR Latches and Priority Switches

So we've already looked at logic gates. They're useful, but they're obviously missing some important functionality. The mechanisms in this chamber are based off of logic gates, yes, but their purposes are more complex. You will see the following devices in this tutorial (listed in order of appearance):

HOLD Gate:

The HOLD gate is used to achieve a permanent effect from one press of a normal button. The button is connected to a laser. This laser points at a relay, which activates two things: the desired output (represented by a flip panel) and a second laser which is also pointing at the relay. Since the second laser powers itself, the relay will still be activating the output, even after you step off the button.

SR Latch (Design 1):

The SR latch, or Set/Reset latch, is essentially a mechanism that has an "on" button and an "off" button. The "on" (or Set) button is connected to a HOLD gate. The "off" (or Reset) button is simply connected to an angled panel which blocks the self-powering laser. Since the laser is powering itself, even a momentary break in the connection is enough to turn it off. This keeps the output in an "off" state.

SR Latch (Design 2):

This SR latch is based on the same principle, but uses a different reset method. The "off" button is connected to a laser that starts enabled. The laser points at a catcher, which is connected to the self-powered laser from the "on" device. Once again, the slight break in the connection is enough to keep the laser off. This type of SR latch is useful when you're building several of the devices with a common reset, as you can connect all of them to the same "start enabled" laser.

Double Input HOLD Gate / NOR-HOLD gate / AND/OR Gate / No official name:

This concept is based off a mechanism made by shane716, though the particular example in this chamber is my design. To activate the output, you need to press both buttons. After you remove one cube, however, the output remains activated. You need to remove both cubes to deactivate it. shane716 calls it a Double Input HOLD Gate, Geneosis calls it a NOR-HOLD gate, I call it an AND/OR gate. There isn't any name that's set in stone, so you can call it whatever you want, really. Anyways, to the device itself. The mechanism is made up of two buttons (cubes are required), plus three lasers and a relay. The first laser (attached to the ceiling) is connected to both buttons. The left laser is connected to the left button and the relay. The right laser is connected to the right button and the relay. The output is connected to the relay. When you press both buttons, the first laser activates. When it does, it powers the relay, activating the two other lasers. When one cube is removed, the centre laser turns off, plus whichever laser is connected to the button that's no longer being pushed. The other laser is still activated, as it's powering itself (in HOLD gate fashion). Once you remove the second cube, the third laser will turn off, for obvious reasons.

Priority Switch (Priority 1):

So, here are my latest creations: priority switches. In this first model, only the first button you press will activate its output (this time, the buttons have separate outputs). This design requires you to set up two lasers, each pointing at a catcher. The lasers should start enabled. Connect each catcher to an output; you should also connect the associated button to the output. Then, connect each laser to the other catcher (the one at which it is not pointing), as well as the button associated with that catcher. When you press the first button, its output will be activated, and the combination of the button and catcher will turn off the other laser. When the second button is pressed, the catcher will still not receive a signal, therefore not yielding an output and not turning off the other laser.

Priority Switch (Priority 2):

This one's a bit more complicated (in terms of connections, not entities). Only the second button you press will have an output. To do that, I will explain later. Sorry, I got bored after writing the previous description. I'll write this one later on.


I hope my descriptions will help if you have trouble understanding anything. If not, then you can ask about it in the comments section, and I will gladly help you out. Any feedback you could give would be wonderful, whether it's positive or negative. Finally, I hope this tutorial gives you inspiration for future chamber building!