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Topic: What kind of motor driver to use for my Chem E car project (Read 1 time) previous topic - next topic

Mond3

Firstly I would like to apologize for level of noobishness displayed in this question.

I am a HND chemical Engineering student in my final year with no background in science whatsoever, I am a commerce graduate who works part of a Hazmat team for Civil defense. I started pursing the course to better improve my understanding of the work I do and I have managed so far withpout the basics. Now for the final semester I am required to prepare a project. I feel I was somewhat forced into taking Chem e Car for the university. Another aspect being this si supposed to be a group project but none of my classmates made it past the first year so I have been the only one in class for the last 1 year.
A brief description of y project:
My project is adapted from: https://scholarcommons.sc.edu/cgi/viewcontent.cgi?article=1006&context=senior_theses
I am preparing a Chem e Car that is powered by thermo electric generators. I am going to have a hot sink and a cold sink with 6-8 thermoelectric generators placed in between them. This should produce the power to run the car. Now as we are not allowed to use gears my detention mechanism is going to be Iodine clock reaction. Potassium iodide is injected into a container containing Hydrogen sufluide which is initially clear, after a few seconds of injection the mixture will go from clear to blue black. Here I am going to use an LDR to detect the color change and have the car come to a stop upon the color change. I understand the chemicals aspects of the project but I have no idea on the electrical aspects of the project. I had purchased an audrino to control the car. Later someone informed me that I need to have a motor driver as well. Turns out there a lot of specifications of motor drivers and I couldn't pinpoint which one to buy due to the lack of information on where to start. So if someone could guide me on which motor driver to buy I would really appreciate it.
Along with the audrino I have picked up Darlington transistor, led and LDR's. Other than the Motor driver would I need to pick up anything else. As my course is for a limited duration I wanted to purchase the relevant materials required for the project so that I can get on ahead to research design and construction of the car.


slipstick

Sorry but you are getting that the wrong way round. You can't buy all the components you need and THEN start designing something. Until you have a design fairly well worked out you have no way to know what components you will need.

So initially, what adaptations are you making to the design in that paper you linked to? From what you've said so far it sounds like you are simply intending to build their design.

A few questions that need answering -

Why do you think you are not allowed to use gears? You will have a lot of trouble finding ungeared motor(s) that will work.

How much power will you get from your thermo electric generators? What voltage/current?

What size is the car? How much will it weigh ready to run?

But fortunately if the car only needs to go forwards you will not need a motor driver. So that's one worry out of the way. But you should replace the Darlington with a MOSFET, which will be more efficient.

BTW what's a "detention mechanism"?

Steve




ardly

Quote
I am a HND chemical Engineering student in my final year with no background in science whatsoever
That does not say a lot for the course then.

Quote
Now as we are not allowed to use gears my detention mechanism is going to be Iodine clock reaction.
As @slipstick said what on earth is a "detention mechanism"?
Also what is the restriction on gears as the paper you referenced states
Quote
However, this speed is also dependent on load and gear ratio. Out of these
parameters, gear ratio is the most significant because it helps to balance
the speed and torque for
our car (8).
"Facts do not cease to exist because they are ignored" - Aldous Huxley

GrooveFlotilla

Quote
A brief description of y project:
At last we can categorically state that this isn't an xy problem.
Some people are like Slinkies.

Not really good for anything, but they bring a smile to your face when pushed down the stairs.

wvmarle

To find an appropriate motor driver, you first need to know what type of motor you're going to use, and your power supply.

The type of motor depends on the power supply - I guess it's a DC supply so that pretty much narrows it down to brushed or brushless. You'll also need to find out the available current and voltage and with it the total power you have for your motor.

OK so now you have chosen your motor(s). Now it is time to figure out how to control them. Select an appropriate driver based on the voltage and current to be switched, and the type of motor you have. Brushed and brushless are quite different in that respect. Brushed is easiest, a MOSFET transistor will do.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

wildbill

While an Iodine clock is a neat trick, I'm not sure what the point of it is - You can control the desired runtime by use of millis directly in the code. The project you're emulating seems to have no real reason either other than 'because we could'.

Mond3

Sorry but you are getting that the wrong way round. You can't buy all the components you need and THEN start designing something. Until you have a design fairly well worked out you have no way to know what components you will need.

So initially, what adaptations are you making to the design in that paper you linked to? From what you've said so far it sounds like you are simply intending to build their design.

A few questions that need answering -

Why do you think you are not allowed to use gears? You will have a lot of trouble finding ungeared motor(s) that will work.

How much power will you get from your thermo electric generators? What voltage/current?

What size is the car? How much will it weigh ready to run?

But fortunately if the car only needs to go forwards you will not need a motor driver. So that's one worry out of the way. But you should replace the Darlington with a MOSFET, which will be more efficient.

BTW what's a "detention mechanism"?

Steve

I'm preparing the exact same project according to the paper. The paper states restriction on gear but my university does not require me to comply with that aspect. Just that they want me to produce a car that dosen't run on battery and is powered by a chemical reaction. I purchased a HR16 4WD car chassis that comeswith 4 motors. I think they have built in gears( can't really figure that out)

http://www.haitronic.cn/index.php?route=product/product&product_id=256

I will be fabricating the reaction containers today after that only will i be able to determine the power output form the thermometric generators. The size of the car smaller than a shoe box about 20*15cm. The weight of the car is yet to be determined. Once the aluminium containers are fabricated and the required reactants are placed I should be able to determine the weight when the car is ready to run.
Yes the car only needs to run forward, So I will consider taking a MOFSET.
Detention mechanism is the stopping mechanism of the car. Here I am required to use an iodine clock reaction as detention mechanism(to stop the car). Initially i was supposed to use photo resistor but then i was advised to use LDR to detect the color change and use the change in resistance to send signal to stop the car.

That does not say a lot for the course then.

As @slipstick said what on earth is a "detention mechanism"?
Also what is the restriction on gears as the paper you referenced states

Level 5 Pearson BTEC Higher National Diploma in Chemical Engineering
Gear restriction does not necessarily need to be applied and neither am I aware of how to implement it
At last we can categorically state that this isn't an xy problem.
hahaha, typo x.x *this
To find an appropriate motor driver, you first need to know what type of motor you're going to use, and your power supply.

The type of motor depends on the power supply - I guess it's a DC supply so that pretty much narrows it down to brushed or brushless. You'll also need to find out the available current and voltage and with it the total power you have for your motor.

OK so now you have chosen your motor(s). Now it is time to figure out how to control them. Select an appropriate driver based on the voltage and current to be switched, and the type of motor you have. Brushed and brushless are quite different in that respect. Brushed is easiest, a MOSFET transistor will do.
How to identify if the motor has brushes, the car chassis kit comes with 4 motors for each wheel.
While an Iodine clock is a neat trick, I'm not sure what the point of it is - You can control the desired runtime by use of millis directly in the code. The project you're emulating seems to have no real reason either other than 'because we could'.
Since it is a chemical engineering project they want most aspects of the project to be a chemical reaction. I had initially suggested Formulation of perfume from plants but they rejected it saying its too simple >.> Now i'm stuck with this and there is not enough help available in this small island.

ardly

...
http://www.haitronic.cn/index.php?route=product/product&product_id=256

I will be fabricating the reaction containers today after that only will i be able to determine the power output form the thermometric generators.

Detention mechanism is the stopping mechanism of the car. Here I am required to use an iodine clock reaction as detention mechanism(to stop the car).

.... Initially i was supposed to use photo resistor but then i was advised to use LDR to detect the color change and use the change in resistance to send signal to stop the car.

....Now i'm stuck with this and there is not enough help available in this small island.
Have you got the chassis kit already as if it is coming from China it may take some time to arrive?

The link does not provide much information. It looks like each motor drives a geared axle that probably has a wheel on one side and a "velocimetry code disk" on the other. It looks like it takes 4 1.5V batteries wired in series, so it is using 6V. Are your generators going to produce 6V?

You also need to consider the current. Once you have the kit it may have more information or you may be able to Google it from part numbers etc.

To me a photo resistor and a Light Dependent Resistor (LDR) are the same thing - maybe somebody else knows different.

You big challenge is probably going to be getting the electrical/mechanical aspects of this right so that enough power is generated to drive the car.

What is the role of the Arduino, could everything not be done by electronics?

What small island are you on?






"Facts do not cease to exist because they are ignored" - Aldous Huxley

wvmarle

Just that they want me to produce a car that dosen't run on battery and is powered by a chemical reaction.
In other words: they're looking for you to build a DIY battery. That's at least what you seem to describe.


Quote
I purchased a HR16 4WD car chassis that comeswith 4 motors. I think they have built in gears( can't really figure that out)
Fair chance - such motors easily do a couple thousand RPM. Too fast for most direct drives.

Quote
How to identify if the motor has brushes,
Short from taking it apart: ask the manufacturer.

Oh, GrooveFlotilla referred to this. I have to agree that it's good to know we're not having yet another xy problem on our hands.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

slipstick

I purchased a HR16 4WD car chassis that comeswith 4 motors. I think they have built in gears( can't really figure that out)
....
How to identify if the motor has brushes
The motors are geared. And if they only have 2 wires to connect them they are almost certainly brushed. Brushless motors almost always have 3 wires.

Steve

wvmarle

My BLDC water pumps and BLDC computer fans all have just two wires.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

PaulS

 
Quote
I'm preparing the exact same project according to the paper.
So, you are not contributing anything new. Hmmm.
The art of getting good answers lies in asking good questions.

slipstick

My BLDC water pumps and BLDC computer fans all have just two wires.
So I was correct, almost all brushless motors have three wires. Then there are components containing brushless motors plus controllers which have only two.

So just for completeness do you have any brushed motors with three wires?

Steve

wvmarle

No. All that I have are two-wire motors. Control is of course limited to simple on/off.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

Mond3

Have you got the chassis kit already as if it is coming from China it may take some time to arrive?

The link does not provide much information. It looks like each motor drives a geared axle that probably has a wheel on one side and a "velocimetry code disk" on the other. It looks like it takes 4 1.5V batteries wired in series, so it is using 6V. Are your generators going to produce 6V?

You also need to consider the current. Once you have the kit it may have more information or you may be able to Google it from part numbers etc.

To me a photo resistor and a Light Dependent Resistor (LDR) are the same thing - maybe somebody else knows different.

You big challenge is probably going to be getting the electrical/mechanical aspects of this right so that enough power is generated to drive the car.

What is the role of the Arduino, could everything not be done by electronics?

What small island are you on?

I purchased the kit from a local shop here. Literally the only shop that sells this here. Only the model number and the picture in the link is displayed. No manual no instructions. So I dont know how much power is required to run it and I dont know yet how much power the thermo electric generators are going to produce. I need to fabricate the containers and sitck the thermo electric generators in betwen and test the output this week but i'm still waiting for  "approval" from the HOD to use the workshop. I would have to wait till Sunday to do this. Oh and I have never been to a workshop before.
Tried googling "HR16 4wd" but other than the link nothing useful comes up.
Honestly, I have heard of Raspberry Pi but not of Audrino. It is listed in the thesis they want me build, that is the first time I heard of Audrino. The guys who did the thesis had a team, I am one the only survivor of this course. I dont suppose the task i want can be done without an Audrino or a Raspberry Pi. Would have been better. I need to apply the chemical aspect, the isntrumentation can change.
I am from the Kingdom of Bahrain. Tis a small island.



In other words: they're looking for you to build a DIY battery. That's at least what you seem to describe.


Fair chance - such motors easily do a couple thousand RPM. Too fast for most direct drives.

Short from taking it apart: ask the manufacturer.

Oh, GrooveFlotilla referred to this. I have to agree that it's good to know we're not having yet another xy problem on our hands.
It never crossed my mind to ask the manufacturer, I will try that now. Thanks
The motors are geared. And if they only have 2 wires to connect them they are almost certainly brushed. Brushless motors almost always have 3 wires.

Steve
The motors have 2 wires. Do I need all 4 motors to run the car?
So, you are not contributing anything new. Hmmm.
Forget about contributing. If I can get this car running I would consider it a miracle. Might I remind you I am a commerce graduate. I still don't understand how only I passed through to the second year.

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