PIC Project Help

[gili6aue]

Hello everyone, my final year project is also based on the same idea. We're using PIC16F84. But our circuit is too complicated and can't seem to understand it. Now we're almost done with the assembly but out sensor based tricycle is not working. Please give me some points to make it work or atleast move.

 

[Ian Rogers]

The reason this post has no hits... answers... is because it's too vague.... What circuit? What assembler? What idea?

 

[gili6aue]

My earlier post was as u call it 'vague'. Here's the information i've on it: Our project topic is 'Model Of Ultrasonic Sensor Based Tricycle Control Using PIC Microcontroller'. We use PIC(PIC16F84A) in order to control two DC motors with gear boxes through motor drive ICs ( TA7257P). I have uploaded the circuit diagram i'm working on. It has been verified by mu project guide but its not working. Please help.
View attachment 64044View attachment 64045

 

[Ian Rogers]

What's not working? Has the code been downloaded "as is"... ie... have you modified the program?... Where did you get the circuit from?

 

[trash]

Are the transducer circuits working as you require ?
The circuit has LEDs on the output of each sensor, are these lighting up and representing a reflected signal ?

Is the output of each of these transducer circuits integrated pulses or are you looking for DC levels ?
The 0.1uF capacitors in combination with the 10K resistors are holding the sensor inputs low.

So it comes down to what is expected from the output of the 74HC04 and what are you actually getting on a CRO before were even consider looking at the PIC coding.

 

[gili6aue]

We are working in a room with leaky roof, maybe due to the recent storm here our components got damaged. Now we are assembling again with new components. The program was modified by our project guide and he's yet to explain it to us and the circuit was a combined work of us and our guide. I'll post as soon as i get more information.

 

[gili6aue]

Hi
unfortunately our LEDs are not lighting up. We had some mishaps with the weather which damaged our components. We're reconstructing the circuit with new components. We're dealing with DC levels. We'll checking the ratings you've mentioned and get back to you. Can you mention some real life applications of this? Is it feasible to use it in a real car? Thanks for the help.

 

[trash]

Do you trust your circuit and your skills to move a car ?
The ultimate test of faith is to stand in it's way. If it runs you down, we'll chalk up another win for evolution over faith

 

[gili6aue]

Good news!!! our tricycle is moving. After rebuilding with new components, we have our tricycle moving. But got a problem with the ultrasonic sensors. the LEDs are not lighting up even if there's obstacle. PLEASE HELP!!!

 

[trash]

Have you considered working back from the LED ?
Do you have a CRO and do you know what waveforms you should be seeing at each stage of the circuit ?

 

[gili6aue]

We are getting the required waveforms, the circuit is connected correctly still its there's no progress. What i don't understand is significance of using specific values of the components. I just want to start with the report writing but i'm stuck in every path

 

[4pyros]

You must walk before you can run. You need to find someone whare you are to explane electronics to you. You can not learn it in a day or get it all explaned to you in a forum.
The problums you are having could be anything from dead batterys to noise to a bad connectoin to bad parts or a wet transducer.

 

[harold777]

I am gasted and flabbered . . . just what is the point of a project that the students don't understand? This is a reflection on the course and examiners, since the teacher is constrained to use whatever subject are set. But it reads like a mess, IMHO.

Apart from anything the use of the 84 shows it's not a modern design, so maybe the college has a few spare pcb's -

Post#10 aims at the heart of the issue. . . the students should check (and understand) how each part works, only then connect them...The PIC cct should have a "Test box" so its inputs and outputs can be tested (without the complication of an attached tricycle).

In industry they may be given a "smoking ruin" to fix -and that means getting to the heart of the inputs...only then can the output behave correctly - and that assumes the software is bang-on . . . . I suspect the Students didn't write the program . . . so what are they learning???

 

[trash]

Yes, I don't get it either Harold. I was recently asked to help a friend's nephew who is doing a 5 year uni course.
He's into his third year and the problem/project which he was given was something I did in a first year of an electrical engineering trade course.
I explained the problem to him and asked him questions about components to use and how to solve the task given to him.
Which he did on his own, and I really didn't give him any help.

So he knew the theory, but seemed to have no ability of how to use what he knew.
A bit like a student being able to spell, but not write a story.

My first impression is that university courses have been seriously dumbed down. The more time students spend studying, the more money they are spending. I can remember when first year university was hard, and this was to get rid of the idiots. Of course now we realise that dumb kids are a cash crop.

The second is that students are taught what to think, not how to think for themselves.

And then there is my favourite. Cheating. I was amazed at how many students cheated. Only once did I see somebody get caught and punished.
Some other students set me up. One asked for some help, which I gave him. While he distracted me, another of his friends copied my work.
A couple of weeks later the group submitted their work. The teacher knew my work and was amazed at how suddenly 8 other very similar examples of source code were submitted. His first response was to question me to see if I had let anybody copy my code. It was clearly my style of programming,
but alterations to the code were only minor. The working sections of code were identical.
Those students failed the subject that semester.
I later discovered that the same code was submitted in other classes in other terms. I then realised that an entire ethnic group was working in house.
Heheh.. yes, I was working me up to some racism It wasn't everybody, but 90% of them that gave the other 10% the bad name.
Several classes of the same subject were held each week. One on Mondays, maybe two on each other weekday which were always really popular and one on Friday nights which only working people picks because there was no other time available.
This group of students, only one or two of them would be in Monday classes. The rest of them were during the week.
The course tests were all the same for each class. So for final exams the Monday night boys would never pass their tests, unless it was by luck.
Instead they would write down the questions, given them or sell them to the rest of the group who would then know the answers to the test.

Most of the teachers didn't care. Since large numbers of students failing looked bad on their record.
Some teachers were honestly concerned and one year one of the head teachers decided to do something about it.
He made the tests as identical as possible, but with only minor changes to the questions to give slightly different answers for each class.

More than half of the students in courses were failing. Even I was shocked at how rampant cheating was. Almost two thirds of students were cheating, and not just the original ethnic group I thought. Thankfully stupidity wasn't confined to just one race.

Even worse was that when students complained that they had failed, before they realised they had been caught in a sting. Some of the teachers stood up and said that there was a racist vendetta against some ethnic groups. Those teachers were asked by the head teachers, were they just bad students that failed or was it because of bad teaching ?
The teachers when shown the test results across classes were stunned to see the same questions had the same answers across five different classes, where the questions all had one value changed. They were asked, is cheating an indication of bad teachers or bad students.

 

[harold777]

Cheating is by definition a bad plan. However, in PIC circuits there is a need to use other peoples work - and Microchip has masses of AP Notes which give the codes. I'm not sure this is "cheating" but maybe "Why re-invent the Wheel" comes to mind.

Maybe we need to go back to Exams, starting with simpler questions....?