ANY-maze Help > The ANY-maze reference > The Protocol page > The elements of a protocol > Inputs and outputs > Analogue outputs > An introduction to analogue outputs

An introduction to analogue outputs

Introduction

An analogue output is simply a voltage which can change based on conditions in a test. This in itself isn't really of any use, but if you have some equipment which can be controlled by a voltage input, then it means you can now control that equipment from ANY-maze. For example, imagine you have a laser which you're using in your tests, and the laser's power can be adjusted by applying a voltage to a connector on it - perhaps 0V means 'off', 1V means 'on at full power', and any voltage in-between means 'on at a proportional power'. If you connect this laser to an analogue output, you could then have ANY-maze adjust the laser's power depending on the situation in a test.

There are really two aspects to analogue outputs in ANY-maze: the generation of the output, and how it is used.

Generating the output

Clearly, to generate an analogue output, you will need some sort of I/O device which includes this type of output - the ANY-maze interface, for example, has two analogue output ports. But that's only half the story - you also need some way to set the output during a test, and ANY-maze provides two options for how this can be done:

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The output can simply track the animal's X or Y position in the apparatus. For example, if an output is tracking the X position, then, as the animal moves to the left, so the output's voltage will go down and as the animal moves right, so the output's voltage will go up. If you use two outputs, you can use one to track the animal's X position and one to track Y.

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The second way to set the output is by using an action in a procedure. As you may know, procedures are a series of instructions which ANY-maze performs while a test is running, so you could create a procedure which would determine what's happening in the test and alter the analogue output voltage accordingly.

For example, imagine you have a foot shocker which has a voltage input to set the shock level, where 0.1V means 1mA shock, 0.2V means 2mA shock, and so on. Now you want to alter the shock the animal will receive based on which corner of a cage it is in. You could do this by creating four zones, one in each corner, and then writing a procedure so that each time the animal enters one of the corner zones, the analogue output would be adjusted, thus causing the shock level to change. Of course, you'd probably also want a second procedure, which would control when the shocks are actually administered.

How an analogue output is used

In the previous section, I've given a couple of examples of equipment which might have a voltage input to which an analogue output could be connected: a laser and a shocker. Doubtless there is other equipment which can be controlled via a voltage input, and if you're wondering whether a piece of equipment in your lab can be controlled in this way, just contact ANY-maze Support and we'll be happy to advise you.

There's a second way an analogue output could be used, and that's to control some device you build yourself. If you're thinking of doing this, then you probably already have a good idea about what an analogue output is (it's just a DAC - a digital to analogue converter) and how you will use it, but, again, if you have questions, just contact us and we'll be happy to help.

ANY-maze help topic T0268