Getting back to the original topic, I think your idea could work, and most likely there is someone already doing it. But theses need not be original. My suggestion would be to investigate how agricultural engineers measure soil moisture. Would it be through soil conductivity (that might be fair for a given soil type)? Or perhaps they put down a probe that senses humidity?

As earlier answers suggested, if you're going to use a microcontroller anyway, you can probably dispense with most of the circuitry and feed the output of the moisture sensor directly into the A/D converter of the microcontroller. Once the information is in digital form, you can compare it to whatever threshold you wish, and it will be better data than just a 3-level dry/ok/waterlogged reading. You can even use it to trigger watering if necessary. Try taking a look at the site http://www.picaxe.com/ . The PICAXE is based on the PIC microcontroller, but they've made things simple so you can just program it in BASIC. Easy to use if you don't enjoy programming, and have only simple needs. The parts are inexpensive, just a few dollars, and development software is free. And they do have A/D converter on the chip, so there's very little else that you need to add to make something work.

I just started the thesis. The problem is that my thesis adviser and most of the panel members are civil engineers. the thesis stated above was the one approved by them because civil engineers find it difficult to measure soil density. I think the moisture sensor that I researched depends on soil conductivity. And I also found a relationship between soil moisture content to that of the soil density by an exponential formula. Someone might be doing it already but not yet successful because I did not hear anybody doing soil test using this method.

regarding the problems, I will be posting later the schematic diagrams.

Thank you!

 

Going back to the original topic, there are not good ways of measuring soil moisture content. Do some research. It has been the topic of many motivated grad. students (both agricultural and engineering students) over the years. Not much useful stuff has come out of it. I searched for a working solution for my Master Gardener wife, and could not find one...

I have supervised Masters thesis and PhD dissertation students and served on their committees. The first question during a defense are always about the scientific principles underlying the project. You can have the most elegant hardware, but if the measurement doesn't hold-up, neither will the defense...

That is my problem too because accordingly, there are a lot of factors affecting soil conductivity and soil density but it will be nice if somebody will start a working solution to the problem and other experts like yourself will improve it based on recommendations.

Thank you!

 

Why don't you take your analogue sensors straight into a micro-controller with a built-in A-D converter? Or, keep the whole thing analogue?

I am not that good in programming analog signals so for me I want to convert the sensor output into digital signal. Since I have a very limited knowledge in microcontrollers, any help is very much welcome.

Thank you!

 

Back to #1, I think the overall approach he describes is not his own, but something described to him or even required of him to use. Also, the three comparators might be frequency discriminators or missing pulse detectors to quantize the current/frequency into four bands. Given the number of non-H2O related variables described above, I don't think an 8-bit A/D would have any more real accuracy than 3/4 of an LM339.

ak

 

Back to #1, I think the overall approach he describes is not his own, but something described to him or even required of him to use. Also, the three comparators might be frequency discriminators or missing pulse detectors to quantize the current/frequency into four bands. Given the number of non-H2O related variables described above, I don't think an 8-bit A/D would have any more real accuracy than 3/4 of an LM339.

ak

You are correct sir about the comparators. I am using 741 as comparator. The circuit was what I presented in my thesis proposal phase that was accepted that is why as much as possible I need to follow it. But if out of options, I can modify the designs.

Thank you!

 

Generally the first part of a thesis is a literature review in which you research and describe the existing state of the art. For something like this that should entail the existing technologies that are used to make these measurements, their levels of performance, and their strengths and shortcomings. That sets the context for the evaluation of your work. Have you done that yet?

 

I am not that good in programming analog signals so for me I want to convert the sensor output into digital signal. Since I have a very limited knowledge in microcontrollers, any help is very much welcome.

May I suggest the following:

• mikroC Compiler
• Microcontroller PIC 16F877a
• K150 Programmer

We will help you write some C code to talk to the peripherals hanging off the microcontroller such as the LCD and sensor(s)

Do you think you'll need any other inputs such as buttons?

 

Generally the first part of a thesis is a literature review in which you research and describe the existing state of the art. For something like this that should entail the existing technologies that are used to make these measurements, their levels of performance, and their strengths and shortcomings. That sets the context for the evaluation of your work. Have you done that yet?

That sounds like the requirements for an pHD in Australia.

 

After reading this thread, and sharing the same concerns as most of the other people involved, I still fail to see how you plan to measure density.
Moisture content could be a straight forward thing if you knew in advance of what minerals the soil is composed and in what proportion.
Are you planning to measure this characteristics directly from the ground? Or are you going to practice the measurements in potted plants.
Is it for exterior application, or for greenhouses?
Again... what are your plans regarding density measurements?

 

That sounds like the requirements for an pHD in Australia.

The difference is generally the extent and nature of the search. In a PhD dissertation you are usually having to establish that your topic is novel and has not been done anywhere before, whereas for a Masters thesis you are usually trying to establish a basis of comparison between what you are doing and what is already out there.

Specific dissertations and theses differ from this, of course, depending on what makes sense for the topic. The PhD is generally governed by the requirement that your work is expanding the overall body of knowledge in that field, while this requirement is not necessarily a requirement for a Masters thesis. This gives a lot of flexibility in defining a Masters thesis and in some cases it is reasonable for the thesis to be an implementation of something that someone else has developed or described.

 

The difference is generally the extent and nature of the search. In a PhD dissertation you are usually having to establish that your topic is novel and has not been done anywhere before, whereas for a Masters thesis you are usually trying to establish a basis of comparison between what you are doing and what is already out there.

Specific dissertations and theses differ from this, of course, depending on what makes sense for the topic. The PhD is generally governed by the requirement that your work is expanding the overall body of knowledge in that field, while this requirement is not necessarily a requirement for a Masters thesis. This gives a lot of flexibility in defining a Masters thesis and in some cases it is reasonable for the thesis to be an implementation of something that someone else has developed or described.

So what you're saying is that originality is one of the key requirements of a PhD?

 

So what you're saying is that originality is one of the key requirements of a PhD?

That's my understanding. I've known people that were ready to defend when someone else published results that mirrored theirs and they had to basically start over. One of my profs had that happen to him three times before he finally got done (he was working in a very hot topic area in which a lot of people were doing basic research and publishing things right and left -- I don't recall what that area was (if I ever knew), but it would have been something in the realm of modern physics in the 1950's or 1960's time frame).

 

That's my understanding. I've known people that were ready to defend when someone else published results that mirrored theirs and they had to basically start over. One of my profs had that happen to him three times before he finally got done (he was working in a very hot topic area in which a lot of people were doing basic research and publishing things right and left -- I don't recall what that area was (if I ever knew), but it would have been something in the realm of modern physics in the 1950's or 1960's time frame).

Yeah... and that was an era in which physics research was smokin' hot...
Anyway, I'm still wondering how the OP intended to measure density... was he going to scoop a sample from the ground?

 

Yeah... and that was an era in which physics research was smokin' hot...
Anyway, I'm still wondering how the OP intended to measure density... was he going to scoop a sample from the ground?[/QUOT

I will face the problem of measuring density after I finish solving the problem of moisture sensor. By the way, my thesis panelists requires that the system is portable so much so that the probe of the system will just be stocked to the ground and tadaaahhh, the readings should be there. I hope I can finish this thesis.

Thank you!

 

May I suggest the following:

• mikroC Compiler
• Microcontroller PIC 16F877a
• K150 Programmer

We will help you write some C code to talk to the peripherals hanging off the microcontroller such as the LCD and sensor(s)

Do you think you'll need any other inputs such as buttons?

My proposal did not require any buttons sir.

Thank you. I will research now on MikroC and microcontrollers.

 

I will face the problem of measuring density after I finish solving the problem of moisture sensor. By the way, my thesis panelists requires that the system is portable so much so that the probe of the system will just be stocked to the ground and tadaaahhh, the readings should be there. I hope I can finish this thesis.

Thank you!

And I hope everything works out for you... but you first have to define the basic principles that you plan to apply ... the best of lucks to you

 

My proposal did not require any buttons sir.
Thank you. I will research now on MikroC and microcontrollers.

As I understand it you are not studying electronics or computer programming here with your masters...

I'll help you out. 5-minute job to get some information shown on an LCD for me. You have not mentioned any particular sensor. If you can provide me with the requirements of the job and the parts to use, then I can draw you an schematic in circuit maker 2000 and write you some C code. I will prototype the project on veroboard and upload photos. You just build the design as you see it in the schematic and photos and purchase an K150 USB programmer to burn the microcontroller chip with the code.

Take me all up an hour tops. Happy to help you out.

Easy greasy...

 

Hello,

@MCU88 , The OP must do the job by himself.
If you do the job for him, that would be cheating and the OP will not learn how to solve the problems.
Please ONLY give HINTS and NOT complete solutions.

Bertus

 

A master's project/thesis is like any other science/engineering design project.

You must address and research the stages separately.

1. Concept
2. Theory
3. Design
4. Implementation
5. Data Collection
6. Analysis

You are attempting to jump into step 4 without doing the due diligence required in steps 1, 2, 3.

1. The concept is to create a tool or process to determine soil conductivity and soil density.

Now you must do the research in steps 2 and 3 before tackling 4.

Forget about what chips, opamps, MCU you hope to use until you have completed steps 2 and 3.

 

A master's project/thesis is like any other science/engineering design project.

You must address and research the stages separately.

1. Concept
2. Theory
3. Design
4. Implementation
5. Data Collection
6. Analysis

You are attempting to jump into step 4 without doing the due diligence required in steps 1, 2, 3.

1. The concept is to create a tool or process to determine soil conductivity and soil density.

Now you must do the research in steps 2 and 3 before tackling 4.

Forget about what chips, opamps, MCU you hope to use until you have completed steps 2 and 3.

And as far as I can see, step number one is not even completed yet. There's a difference between an idea, and it's conceptual essence. For example:
idea: let's make a machine that flies
concept: We'll use a hot air balloon!
So far you only have the idea, but have not yet determined the concept and much less the theory.