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76  Using Arduino / Project Guidance / Re: first robot on: February 19, 2014, 02:01:34 pm
i wont make it wireless i only want the code to upload to the arduino uno so that will work like that ( i am a total noob at this)

Guess how you stop being a "total noob"?

You get in there, and you do the work. It starts with identifying your problems, breaking them up into sub-tasks, then building the code to solve those sub-tasks.

Have you already gone through all of the tutorials that came with the Arduino, and do you understand how they work?

If you have, then you should have a good base to work from.

Have you researched how others have implemented small robots using the Arduino? There are tons of forums and sites (such as "lets make robots" and "instructables") which have numerous tutorials and how-to's on building such robots. You aren't doing anything new, and there is tons of source code and hardware designs out there to learn from.

Your plaintive cry for source code just to make it work is likely going to fall on deaf ears, because you haven't even shown any propensity (thus far) to ameliorate your own ignorance. One simple google search is all it will take, and using what you find to make some sort of code you can present here for us to look at and make suggestions.

You are not a baby. You do not need to be spoon-fed this information. The information is already out there. Find it (or, as my parents would tell me, "Look it up in the dictionary/encyclopedia yourself!").
77  Using Arduino / Project Guidance / Re: Navigation system for autnomous lawnmower on: February 18, 2014, 08:47:18 pm
I am thinking of using a accelerometer to calculate distance. Ultrasonic sensor to help maneuver around objects and a compass to make sure the lawnmower always follows a correct path even when taken off path by maneuvering around an object. Is this a possible way for a navigation system? Also what compass do you recommend me using?

What you are describing is called a "dead reckoning" system. This won't work for any long periods of running (though can be useful when other, more accurate methods aren't available - such as when you are using DGPS and suddenly find yourself without signal).

You might want to keep such a system as a backup option, though.

There aren't many other options available - that at least are simple. You could always try some form of SLAM, if you are so inclined (perhaps building a map using sonar, IR, and cameras) - note that this takes it out of the Arduino range of microcontrollers (you would probably need to feed the sensor readings back to a PC or something, and integrate from there).

Another option might be to (somehow) place a "random" layout of magnets on the lawn (small rare-earth magnets epoxied to plastic golf tees), and then add a ring of hall-effect sensors to the robot to detect the magnets as they passed over, ultimately building up a map that way (plus using some SLAM techniques to build up a probability distribution of the map so you can roughly tell where you are at).

Alternatively, you could set up closely spaced magnets as a "trail" (kinda a passive form of a buried wire - which I assume you are trying to avoid?)...

If there aren't any obstacles in the way around the robot - you could set up ultrasonic receivers around the yard, then mount a spinning transmitter on the robot - and ping; the angle of the transmitter to the receivers plus some triangulation could give you a rough location estimate.

No single one of these solutions will give you anything perfect or accurate, but a combination can ultimately help.
78  Topics / Robotics / Re: Does a PowerWheels motor need to be powered by a chunky 6v? on: February 18, 2014, 08:33:13 pm
I have acquired an older PowerWheels motor and gearbox from a Kawasaki trike.

Do you have more information than this - because there were multiple Kawasaki Power Wheels made:

http://service.mattel.com/us/instruction_sheets_results.asp?brand=168

The closest I could guess based on your limited information was the "W6214 - Lil Kawasaki" - which was a small, single motor 6V ride-on toy (though that shows it as a quad, not a trike). The link for the 6V battery manual details that the battery has a 25 amp fuse, but the manual for the toy itself says it is a thermal fuse.

So I would say it is some kind of resettable fuse, rated at 25 amps. That would mean (if this is the same vehicle) that your motor can pull at least 25 amps when stalled, possibly more. When running and no load, it probably pulls at least an amp, maybe more. When loaded, you can figure 5-10 amps.

Without measurements or some other details - we'll just be guessing, so you need to do some more research or take some measurements for us.

That said - that kind of a number for amperage on those motors is about correct; they are fairly beefy things. In short, an L293 and 4 AA batteries will not cut it for this motor.

For a battery, you will need basically the same thing the ride on toy used - a 6V 4 aH (or better amp-hour) battery. You will want to put an inline fuse as well (as close to the positive on the battery as possible) - of whatever amperage was originally specified (or start with 10A and increase to 25 if it keeps blowing).

For the h-bridge, you're going to need something beefier - check pololu for something with a rating of around 30 amps (you size based on stall current plus around 20% extra).
79  General Category / General Discussion / Re: delay on: February 17, 2014, 05:45:46 pm
can the delay in a sketch be controlled externally from the sketch

Do you mean something like:

Code:
delay(analogRead(pin)); // delay up to approx. 1 second based on reading from analog input

I mean - that would work, but it wouldn't be the best way for your code to be written because delay() is a blocking function; you could, though, do something similar that isn't blocking, once you understand how the "blink without delay" example sketch works:

http://arduino.cc/en/Tutorial/BlinkWithoutDelay#.UwKTNEkS0ss
80  General Category / General Discussion / Re: Please help, Using arduino programing without a board? on: February 17, 2014, 01:12:23 pm
Can anyone tell me, if it is possible to somehow use Arduino programming language and not use a board, as I do not have one?

Well - you can use it, but it won't get your very far without an Arduino-compatible microcontroller to upload the code to...

I want to program a questionnaire and that it would be able for the viewer to answer questions serial monitor? or does this program have no such possibilities???

If you want to use something similar to the Arduino code, I would suggest Processing:

http://processing.org/
81  Using Arduino / Motors, Mechanics, and Power / Re: RC car Front motor on: February 17, 2014, 12:56:01 pm
Most likely you will need another h-bridge for the motor.

I assume (without having any other information from you about the car) that the RC car you are using is some cheap toy vehicle? If so, then it simply uses a small toy motor for the full left/right actuation of the steering (this is called "bang-bang" control - since the motor turns the steering against the stops).

You need to measure the amount of current this motor consumes when it is actuated against the stops (this is called the stall current), and you will need an h-bridge with a continuous current output rating greater than this amount (at least 15-20% would be ideal). Likely you can get away with something low cost, because the stall current will likely not be greater than 1-2 amps (if that).

Again - note that this control doesn't allow you any kind of "proportional" angle of steering - just full-left and full-right control. If you need or want proportional (where you can smoothly vary the angle from center to full-left, right, or anywhere in between) - you will need to replace the current actuator with an actual RC servo; doing so can be fairly easily done, but may require a bit of mechanical ingenuity in order to properly locate and connect up the servo to the wheels to steer them properly.

In regards to the current actuator, though, I must ask why you didn't just keep the RC receiver and interface to that, as it has on-board all the h-bridge and other controls needed for the car? It wouldn't be as easy to hack this, but it might have saved you a bit of money (unless it was already broken in some manner of course).

Also - have you read through this thread?

http://forum.arduino.cc/index.php/topic,86883.0.html

It might not help you now if you have already removed the RC receiver (or if it was broken), but you might want to bookmark it for the future...

Good luck with your project!
82  Using Arduino / Motors, Mechanics, and Power / Re: Geared stepper motor on: February 17, 2014, 12:47:00 pm
The description is quite clear...in other words they have put an inadequate gearbox on the motor!

After reading the description myself, you are quite correct! I wonder how many people break those?

I had a DC gear-motor (purchased surplus for $10.00) that easily generated enough torque to break it's output gear when stalled (steel gears, too); I found this out the hard way. I contacted the sales rep for the company that currently manufactures the motors, and they could sell me replacement gears, but they had a minimum order quantity of 50 pieces, at $7.00 USD each! I passed on that, and purchased another motor instead.
83  Using Arduino / General Electronics / Re: SMD Soldering - do I need Hot Air Soldering Station? on: February 17, 2014, 12:41:24 pm
Is there any method to resolder that using normal soldering iron?

I've never worked with SMT parts, but from what I have gathered, the key things in order to use a "normal" soldering iron are:

1. Temperature control
2. A fine tip
3. Flux - lots of flux (more for fine-pitch ICs than for discrete components, though)

I have an old Hakko soldering iron (909 or 911, can't remember) that has extremely fine soldering iron tips for SMT work, plus temperature control - so you want something like that; if you find yourself doing a lot of rework, hot-air works well for removal and reflow, but not so much for discrete components as the hot air will just blow them off (unless you anchor them in place on the pads with a drop of super-glue or something).

As for flux - it's important mainly for ICs with a lot of pins; you need liquid flux for this, and you basically want to flood the pins with flux, then run your solder over the pins (and you may still need to do some cleanup afterward with braid).

But again - this is just what I have read (and watched videos of) - I don't have any experience (haven't had the need yet). I would also second the recommendation of practising on something else first to get the hang of things.
84  Using Arduino / Project Guidance / Re: Scientific Atmospheric Data Collection for Paranormal Investigation on: February 17, 2014, 12:25:18 pm
Note: I am just reading this thread being amused by the absurdity of it all. I mean, before you detect a "ghost", you have to at least a hypothesis of what a ghost is, how it came about, why it came about, why they exist, etc - just to have a concept or clue as to how to detect one.

You should also be aware that the mind and the brain are very complex, and can be easily fooled, either from within or from without. When fooled, and without extreme sceptical prejudice and contemplation (and sometimes, not even then!) - the mind will make up narratives to fill in the blanks and make sense of the situation.

In short, memories are nothing more than imperfect models of what has been sensed in the "real world". Numerous research studies have shown this to be true, thus far. Such insights are being used for therapy (such as mirror therapy for amputees with phantom limb pain).

I can almost guarantee you that you have not seen a ghost; what you saw was either an optical illusion or some other trick played upon your eyes, or some sort of hallucination - either something random your mind made up, or potentially something caused by a medical issue.

If this "ghost" hallucination was real enough (and/or you have had other symptoms - flashes of "light", dizzyness, slurred speech, hearing noises, etc), you might want to first be checked out to make sure you don't have some form of tumor, unknown aneurysm, or some other condition that is causing a problem.

BTW, why is everybody, including me, shouting?

Nobody is shouting that I can see:

1. THIS IS SHOUTING.
2. This is writing in a normal "tone" of voice.
3. this is just being lazy
85  Using Arduino / Motors, Mechanics, and Power / Re: Power issues, PLEASE HELP on: February 16, 2014, 08:04:45 pm
Your entire circuit is probably drawing too much current; a 9 volt PPA (square battery) can't supply enough current, causing a voltage sag and (likely) resetting the Arduino...
86  Using Arduino / General Electronics / Re: 110/220V to 72V Power Supply in Parallel? (formerly HV...) on: February 16, 2014, 08:02:22 pm
Thanks for info on voltage ranges. I guess I've been reading too much about, and labeling of, the high vs low voltage sections (i.e., 220V vs the 5V logic) of the system.

Better terminology would be "AC mains voltage" vs "DC logic voltage" - or something similar.
87  Using Arduino / General Electronics / Re: is L293D diffrent from a H_Bridge?? or PCB ones! on: February 16, 2014, 01:20:31 pm
in iran its not like you chose beetween models and go find on stores its like this ou go to store and make list of all and make a choice smiley-grin but thanks so much

You may not have such a wide range of choice or be able to find such (or purchase) online in Iran - but that doesn't mean you should ignore what MarkT wrote. You should size things first, then fit the driver to what you have found for size, otherwise you are just operating blindly, and will likely spend more money burning through parts than you would have otherwise.

Even if your choices are limited to a subset of available h-bridge IC designs (and old ones at that - though I don't discount them entirely, as long as you understand what they were originally designed for - and that is for systems in general operating between 12 and 24 volts - typically older automotive designs) - you should still have the information about what you need for the design before you purchase parts.

At least then - if none of the available IC h-bridges will suit you - you can decide to build a discrete component h-bridge (which isn't generally recommended - but in your case may be necessary).

i dont have multimeter so i can't see my motors stats !!!!

Then you should beg, borrow, steal or build one before you go further.

In fact, building your own multimeter will teach you more about electronic design and function than just about any other project; you'll gain a ton of knowledge on the subject, and have a great tool to help you move forward with your projects. You could build such a device using discrete components (likely with an analog meter movement), or you could build it using an Arduino (or likely, in the finished version, a "standalone arduino" circuit).

Note that whatever you do build likely won't be very accurate (without being able to compare the results with a high-accuracy commercial meter) - but it will be better than nothing; one hint: Whether you decide to go with a discrete component design, or use an Arduino, choose any external components (resistors and such) to have as small of a tolerance as you can purchase and afford (for instance, in a balanced Wheatstone bridge of a discrete component analog design, you want your known resistances to be 1% tolerance or less; preferably much less). You also want to use quality construction techniques for the final implementation - they more accurate the parts you use and the more quality and accurate your construction, the more accurate the final meter will be.

i use gearbox that uses 1 motors and rotates 2 wheels eachside !!! i can post pic if interested!

You can do that, and it may help us somewhat to help you select a proper h-bridge, but even so it will still likely only be a guess, because manufacturers can construct motors that look identical on the surface, but have wildly differing electrical specifications, depending on what application they were originally designed for. Even so, it couldn't hurt - but you should really try to obtain a multimeter of some sort (if you can't afford one, look into splitting up the cost with a group of like-minded friends, perhaps - start an "electronics club" or similar - your own "hackerspace" in Iran, if you will).
88  Using Arduino / General Electronics / Re: HV Power Supply in Parallel? on: February 16, 2014, 01:03:30 pm
For the future, C2 - when you post something with the acronym "HV" - you are meaning "High Voltage" - which for most people in electronics generally translates into anything at 1000 volts or greater (ie - microwave and neon sign transformers, tesla coils, etc).

Your transformer is -not- an HV transformer.

Given your title, I was expecting a completely different question from what was posted, simply because of the term you used; if you continue to use such a term incorrectly, you may cause similar confusion to others in both this and other forums.
89  Using Arduino / Project Guidance / Re: Is it possible to make more pins high at the same time ? (in 1 instruction) on: February 15, 2014, 04:31:42 pm
http://arduino.cc/en/Reference/PortManipulation
90  General Category / General Discussion / Re: visual basic express on: February 15, 2014, 01:05:59 pm
Anyone know of a safe website that i can download VB from? There are so many, but I don't want to download from just any site out there. Thanks!

This is microsoft's website:

http://www.visualstudio.com/en-US/products/visual-studio-express-vs
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