I think the direction we are headed here is, what is anything ORed with itself?

a+a = ?

Then realize you are doing this to the normal operation indicator signal.


The "should" wording in your initial post regarding the sensors Ia, Ib, and Ic sounds like requirements which leads me to think you are supposed to design these too.

...to what end?

What is a*a=?

What WBahn is saying is that one would typically make the warning buzzer active high (activated by a logic 1) and the normal operation indicator active low (activated by a logic 0), or vice versa, so the two outputs are determined by the state of a single output.

Yeah thays what im saying or atleast trying to say but ill use an AND gate instead of an OR gate as when my inputs are 0 , 1 , 1or anything else than because of AND gate my normal condition will have 0Active low at its output and warning buzzer will also have 0 (OFF as warning needs an active HIGH to be activated) or vice versa and about the sensor logic I have no idea of how to make the sensor logic can you guide me please.

 

[...]and about the sensor logic I have no idea of how to make the sensor logic can you guide me please.

That is even easier than what you just did. Assume you have four level sensors arranged such that each sensor is placed along the height of the container and outputs a logic high when the contents reach the height of the sensor.

These four sensor outputs are fed into the sensor logic components Ia, Ib, and Ic, which must output a logic high when the ingredients reach a certain volume.

Note: being creative with the sensors would allow you to bypass this whole step, but I'll assume it is required to make a combinational circuit to accomplish this task.

So, write out your truth tables for each and their corresponding outputs...

 

That is even easier than what you just did. Assume you have four level sensors arranged such that each sensor is placed along the height of the container and outputs a logic high when the contents reach the height of the sensor.

These four sensor outputs are fed into the sensor logic components Ia, Ib, and Ic, which must output a logic high when the ingredients reach a certain volume.

Note: being creative with the sensors would allow you to bypass this whole step, but I'll assume it is required to make a combinational circuit to accomplish this task.

So, write out your truth tables for each and their corresponding outputs...

I don't understand about the truth table that how can I know if my value is 8 or not is it like this:

A B C D output
0 0 0 0 0
0 0 0 1 0
0 0 1 0 0
0 0 1 1 0
0 1 0 0 0
0 1 0 1 0
0 1 1 0 0
0 1 1 1 0
1 0 0 0 1
1 0 0 1 0
1 0 1 0 0
1 0 1 1 0
1 1 0 0 0
1 1 0 1 0
1 1 1 0 0
1 1 1 1 0
as 1000 = 8 in binary?

 

You need to know if it is equal to or greater than 8.

I'm picturing something like this image here:

taken from this page in the eBook.

 

You need to know if it is equal to or greater than 8.

I'm picturing something like this image here:

taken from this page in the eBook.

sorry but I just dont understand this logic our professor hasn't taught any of these things

what I just understand is this :

I have 4 ingredients in Ia so when it's quantity is = 8 it should output a high so if we go like this : 8 4 2 1

so my 8 is A.
In Ib:
my 4 is f as 8 4 2 1
and in Ic:

it's k
sorry but I just don't understand what kind of truth table will I have to make or what sort of diagram wil I have to make.

 

The process I'm describing should not be one that needs to be taught to you - take a moment and think about it. If you have sensors that output a logic high when the contents are in contact with it and the sensor is at a specific height H, then you can use the sensor's output to determine if the contents are below H, right? Add a few more sensors at varying heights and you can measure if the contents are below multiple points.

If you use four sensors, each at a different heights, then your sensors will output 0000,0001,0011,0111,1111 as the container fills. If this correlated to the quantity of units of the contents of the container, and the container will output a logic high if at or above 4, then any state after 0011 as the container fills will output a logic high.

 

I've largely stopped following this thread (distracted by other things) so I might have missed something, but didn't the original specs say that the sensors for the ingredient containers only put out a HI if the containers contains exactly the right amount of ingredients (as opposed to at least some minimum amount). I pictured in my mind something that is going to simply dump all of the containers that are HI into the mixer, hence the need to sound a warning buzzer if all three are HI.

 

I've largely stopped following this thread (distracted by other things) so I might have missed something, but didn't the original specs say that the sensors for the ingredient containers only put out a HI if the containers contains exactly the right amount of ingredients (as opposed to at least some minimum amount). I pictured in my mind something that is going to simply dump all of the containers that are HI into the mixer, hence the need to sound a warning buzzer if all three are HI.

That's also a valid view. It depends on the ultimate desire operation of the device is, which you don't really get with such a small description of the operation. I would think that the sensors would be placed as I described, but there is nothing indicating they are any certain way. If my interpretation is correct, this is how I'd go about it, but as you've pointed out, there is more than one way to read it.

My approach allows one to ultimately bypass any real logic and simply wire a sensor to the mixer controller circuit, without intervening logic.

Unfortunately, we don't have the professor here to elaborate.

@OP, maybe it's time you asked your professor for clarification as to the requirements of the assignment...

 

Hey thanks for the replies... sorry my exams were started so I coudn't come online... I can't understand the sensor logic though I need some one who could teach me face to face so will ask a friend anyway thanks for all the help and replies my digital electronics exam is this wednesday wish me luck