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Author Topic: Help with brainstorming project  (Read 1002 times)

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Offline germz12Topic starter

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Help with brainstorming project
« on: January 31, 2011, 03:03:35 AM »
Hello, I am in no means a troll; this is my first threat and I didn't know who else to ask, then I found this website, so here it goes.

I want to embark on a small project. "A spinning sign." Boring right? I know I know.

Simple enough yet, I have no clue what the parts are called. I took a robotics class in high school years ago, and I remember building small vehicles that moved however we programmed them, had color and light sensors, and even small functional claws. I have what I want to make drawn in my head, but when I sit myself down to search for the materials and parts, I go blank.

I want to make a rectangular billboard 20"X60" or 20"x50" using light weight material up on a metal pole (the normal fence type of pole) I want it to spin not too fast, enough to be noticed, stop at a horizontal level, then spin again, programmed to do so every half a minute or so.

I'd like a double shaft motor to be in between two billboards so that both will spin at the same time and stop at the same time.

I want it to be powered by a small solar panel at the top, at the same time charging a storage battery. When it becomes dawn to night time. I want a sensor to sense that and turn on small LED lights.

I don't know what the board/module thing is called that one programs. For this example to control the motors. (can the RPM of the motor be controlled this way?)

My main concern is not getting help for building the pole and the sign on top. I need a mentor to tell me what to look for to actually make something like this. What kind of motor, how big of a motor, what battery, what solar panel, sensors that detect darkness. Etc...

I know I'm a newbie with this, and I hope there is someone with enough patience to guide me a bit here if you'd be so kind.

Thank you all, great forum, I'm excited!




Offline hopslink

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Re: Help with brainstorming project
« Reply #1 on: January 31, 2011, 04:01:13 AM »
Boring? No. There are plenty of challenges there.

Suggest you start reading the tutorials on this site. You will find most of the background information you need to get going. Suggested starting points include Microcontrollers, DC Motors, Photoresistors and Dynamics.

This should give you some ideas.

Offline nickc

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Re: Help with brainstorming project
« Reply #2 on: January 31, 2011, 02:23:32 PM »
Here's another place to get ideas and ask questions.  Lots of projects shown here as well.

http://arduino.cc/en/

Offline Soeren

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Re: Help with brainstorming project
« Reply #3 on: January 31, 2011, 04:48:50 PM »
Hi,

[...] this is my first threat
Now we're scared  ;)


I'd like a double shaft motor to be in between two billboards so that both will spin at the same time and stop at the same time.
I'd place them on a common axle with something like a bicycle chain leading to a single shafted motor mounted lower.


I want it to be powered by a small solar panel at the top, at the same time charging a storage battery.
That won't do, unless your apprehension of "small" is different from mine.
How large a panel it will take depends on the needed power for the motor, LED's etc.
You also need to factor in that a panel (and the boards) need to cope with whatever wind speeds are possible where you plan to place it and the higher up, the more wind force (usually).


When it becomes dawn to night time. I want a sensor to sense that and turn on small LED lights.
You can use the solar panel to that effect as well, no need for extra sensors.


I don't know what the board/module thing is called that one programs. For this example to control the motors. (can the RPM of the motor be controlled this way?)
A microcontroller is what you want to program and yes, it can be used to control speed - but I gather you just want a single speed, so it's best to use gearing to keep the power at max.


What kind of motor, how big of a motor, what battery, what solar panel, sensors that detect darkness. Etc...
A common DC motor would be the obvious choice, as it is quite straightforward to use.
The size of it can be found when the size, weight, speed etc. of the boards and the construction of the spinning axle is planned through.
The battery will have to be of the voltage needed by the motor, with a capacity suited to buffer the thing through the night (following a rainy day or several) and the solar panel will have to be calculated for this as well and it has to be able to deliver throughout the temperature range it will see.


I know I'm a newbie with this, and I hope there is someone with enough patience to guide me a bit here if you'd be so kind.
No problem. I assume you do have the basic tools and instruments (a DMM at the very least)?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline Soeren

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Re: Help with brainstorming project
« Reply #4 on: January 31, 2011, 04:51:02 PM »
Here's another place to get ideas and ask questions.  Lots of projects shown here as well.
A bit strange answering a question here by telling people to go somewhere else??
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline mr roboto

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Re: Help with brainstorming project
« Reply #5 on: February 01, 2011, 10:41:11 PM »
you might want to go to society of robots website and look at the parts list. that might ring a bell on what the parts are called.
I once though that my brain was the most wonderful part of my body. then i realized who was telling me this

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Offline germz12Topic starter

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Re: Help with brainstorming project
« Reply #6 on: February 02, 2011, 03:44:36 AM »
Boring? No. There are plenty of challenges there.

Suggest you start reading the tutorials on this site. You will find most of the background information you need to get going. Suggested starting points include Microcontrollers, DC Motors, Photoresistors and Dynamics.

This should give you some ideas.



Good read, I thank you for pointing them to me.

Offline germz12Topic starter

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Re: Help with brainstorming project
« Reply #7 on: February 02, 2011, 04:28:42 AM »
Hi,
Now we're scared  ;)
Hello Soeren and sorry for my typo, put it sure fits in, you can read it both ways  ;D
Thank you for taking the time to go over this with me, it has doubled my excitement now that things look a lot more clear.


I'd place them on a common axle with something like a bicycle chain leading to a single shafted motor mounted lower.

Didn't think of that, and should give the desired motion now that I've changed my mind about something. I don't think I should have the boards spin. I can't imagine how I would have LED's lighting the boards if they are going to be attached to the board's frame with wires. When it comes time to spin, the wires are going to tangle unless I make it spin clockwise and then counterclockwise with enough wire that it doesn't tangle up, that should work, however I like the idea of having them only swing from left to right (like a grandfather clock) as my first project. Should keep things simple no? Is this rocking motion programmable? Or will I know need two different motors? From what I know in order to make a motor spin the other direction you switch the wires over.


That won't do, unless your apprehension of "small" is different from mine.
How large a panel it will take depends on the needed power for the motor, LED's etc.
You also need to factor in that a panel (and the boards) need to cope with whatever wind speeds are possible where you plan to place it and the higher up, the more wind force (usually).

My small is, hmm, the size of the panels you see on top of the emergency call boxes in some freeways. Is that still too small?
The height of the pole won't be too high up, up to the same height of a stop sign or a bit higher to keep people from trying to smack or break the thing. I'll try my best to make the boards as light as possible, I'm thinking a thin aluminum frame with a light weight clear plastic panel and make the thing water proof, have an opening to slide in custom made banners.


You can use the solar panel to that effect as well, no need for extra sensors.

That will save me some money and that is always good to know. More money for a bigger panel? ;D

A microcontroller is what you want to program and yes, it can be used to control speed - but I gather you just want a single speed, so it's best to use gearing to keep the power at max.

I assume a low voltage microcontroller will be the most ideal, with the least of features since I only want it for programming the motors "rocking chair" motion and the LED's. If I can save battery life and money here I'd be happy. What would you recommend for this?

A common DC motor would be the obvious choice, as it is quite straightforward to use.
The size of it can be found when the size, weight, speed etc. of the boards and the construction of the spinning axle is planned through.
The battery will have to be of the voltage needed by the motor, with a capacity suited to buffer the thing through the night (following a rainy day or several) and the solar panel will have to be calculated for this as well and it has to be able to deliver throughout the temperature range it will see.

The motor would have to have good torque I assume, yes? I was thinking of getting a used electric ride on toy cars for kids, those things have very strong motors and it even comes with a battery and the charging port, saves me the hassle of shopping around plus those motors go forward and backwards all ready so the wiring should be set up for me? (I just thought of it a few minutes ago  8) ) The LED's would only have to be on until 2-3 hours of night time then they would be turned off or let die off. Hopefully that would make things simpler for me since the charging part seems like the highest challenge. It won't be operational during rain, I will just have to accept that, there wont be any way to wire it to a DC Jack where I want to place it.

No problem. I assume you do have the basic tools and instruments (a DMM at the very least)?

My DMM broke as it was a harbor freight one and not very durable. I have lots of automotive tools as my main hobby is working on my older cars, none of them run at the moment  :P I have a buddy with a mig and tig welder, DMM, sodder, I should be fine.

Once again thank you for your time inputting informative, helpful, responses. I will start gathering parts once I know where and what to get.  

« Last Edit: February 02, 2011, 04:44:29 AM by germz12 »

Offline germz12Topic starter

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Re: Help with brainstorming project
« Reply #8 on: February 02, 2011, 04:30:43 AM »
you might want to go to society of robots website and look at the parts list. that might ring a bell on what the parts are called.

Sure rang some bells, thank you mr roboto.

Offline Soeren

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Re: Help with brainstorming project
« Reply #9 on: February 02, 2011, 06:52:59 PM »
Hi,

Didn't think of that, and should give the desired motion now that I've changed my mind about something. I don't think I should have the boards spin. I can't imagine how I would have LED's lighting the boards if they are going to be attached to the board's frame with wires. When it comes time to spin, the wires are going to tangle unless I make it spin clockwise and then counterclockwise with enough wire that it doesn't tangle up, that should work, however I like the idea of having them only swing from left to right (like a grandfather clock) as my first project.

My greatest concern is with the wind catching the boards. If possible, some holes or slits will help reduce the force though.
Whether you want it to spin , swing or perhaps rotate around the length of the boards, everything is possible and while I don't know how many Watts of LED light you need(?), that could be done by coils and magnets, in effect creating a small generator for the LED's (with the magnets stationary and the coils on the boards). That would use the power from the motor (with some loss) and would nullify wiring problems. However, it's probably better left to after you've got this one working.

To make it swing like a pendulum, a couple of optical couplers (interrupters/reading forks) like this could be used to sense the extreme positions.
Their output changes when something opaque is blocking the (infrared) light from emitter to receiver.


Should keep things simple no? Is this rocking motion programmable? Or will I know need two different motors? From what I know in order to make a motor spin the other direction you switch the wires over.

Yes, it's fully programmable, whether you use an H-bridge or a relay to reverse the current through the motor.


My small is, hmm, the size of the panels you see on top of the emergency call boxes in some freeways. Is that still too small?

I'm a Dane and my only first hand experience with the US is a short week in Charlotte, NC and I must admit that the limo's hauling my sorry *** around were too comfy for observing the finer parts of your emergency infrastructure whooshing by  ;D
So, an approximate measure would help.

For reference: I recently got some panels (meant for top-up charging of 12V car batteries) and they're about 4"x12" and 12"x12" (active area) and give ~90mA and ~275mA (in full sun) respectively.

Not knowing what motor you'll end up with, it's too soon to tell how large a panel you'll need, but counter-balancing the boards and perhaps adjusting the time in between activations would help towards using the leanest possible motor (current draw).

T.ex. charging with 100mA for 60 seconds will enable a draw of say 1.8A for 2 seconds with a 60% efficiency (charging and mechanical losses).

You might consider a small wind powered generator on top of the pole for a possible extension of the project (more below).


The height of the pole won't be too high up, up to the same height of a stop sign or a bit higher to keep people from trying to smack or break the thing. I'll try my best to make the boards as light as possible, I'm thinking a thin aluminum frame with a light weight clear plastic panel and make the thing water proof, have an opening to slide in custom made banners.

Since the US is considered the lawyers Paradise, I'd make real sure it couldn't break off, fall down and scare someones cat (or decapitate the owner).
Weight isn't the major issue here (it can and should be counter-balanced), rigidity and resistance to wind is - as mentioned, some vents may help.


That will save me some money and that is always good to know. More money for a bigger panel? ;D

Or the opto couplers, should you choose to go that route :)


I assume a low voltage microcontroller will be the most ideal, with the least of features since I only want it for programming the motors "rocking chair" motion and the LED's. If I can save battery life and money here I'd be happy. What would you recommend for this?

Controllers are quite cheap (they ought to be, they're mainly plastic and sand ;D) and the features you don't use won't get in the way, so whether you're using the tiniest 6 pin controller or eg. a 40 pin beast with 100 times the "horsepower" you need, the difference is just a few bucks.
Until you reveal the amount of LED's and how you want them controlled, it's difficult to recommend any single controller.

There's different microcontroller "families". Most people here use AVR controllers from Atmel, while I mainly use PIC controllers from Microchip (since most of my other development tools is presently packed away), so if you wan't my help in programming the beast, it will have to be a PIC. Apart from that, each family has controllers ranging from 6 pins to 100 pins+, with the cheapest going at around 50 cents and eg. an 18 pin controller can be had at around $1,- to $1.5.

They all run from somewhere between 1.8V to 5V (some PIC's can handle 15V as they have a regulator built in).

All can control 12V devices through transistors.


The motor would have to have good torque I assume, yes?

Right, but gearing down a motor increases torque, so you cannot look at one of the parameters alone.
It all comes down to how much force it has to exert in how little time.


I was thinking of getting a used electric ride on toy cars for kids, those things have very strong motors and it even comes with a battery and the charging port, saves me the hassle of shopping around plus those motors go forward and backwards all ready so the wiring should be set up for me? (I just thought of it a few minutes ago  8) )

I think that would be overkill, but better "over" than "under" :)
Even if there is a sort of front/back controller, you'd still need something the controller can use.

If you're spending lots of time tinkering on cars, you probably have a spare wiper motor lying around (or can get a good, used one for cheap) I think you have the needed power and automotive relays are just the ticket to control forward/reverse.


The LED's would only have to be on until 2-3 hours of night time then they would be turned off or let die off. Hopefully that would make things simpler for me since the charging part seems like the highest challenge. It won't be operational during rain, I will just have to accept that, there wont be any way to wire it to a DC Jack where I want to place it.

As mentioned, a small wind mill/turbine like a Savonious rotor would help (perhaps even render the solar panel obsolete) and you should take a quick look at this and this, if nothing else, just to know what can be done for next to nothing.


My DMM broke as it was a harbor freight one and not very durable. I have lots of automotive tools as my main hobby is working on my older cars, none of them run at the moment  :P I have a buddy with a mig and tig welder, DMM, sodder, I should be fine.

I think it rather broke because you manhandled it  :P  ;D


Once again thank you for your time inputting informative, helpful, responses. I will start gathering parts once I know where and what to get.  

You're welcome.
Don't start gathering stuff just yet. You should decide on the final outlay first. It's annoying to find that you've bought the wrong stuff.

If you tell me your plans for LED's (amount, how they're going to be driven - on, flashing, running or whatever) and what thoughts you have on using a wiper motor (if you have on handy, please measure the current draw), etc. we can get it a couple of steps closer to shopping time.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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