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10561  Using Arduino / Project Guidance / Re: Using serial port on Uno on: February 26, 2011, 11:37:03 am
The latest NSS library uses interrupts and a received character buffer to handle incoming serial data, just like the hardware serial handler.

10562  Using Arduino / Motors, Mechanics, and Power / Re: Servos: backlash + noise? on: February 26, 2011, 11:24:52 am
Noobie servo questions:

I haven't worked with servos before and I'm wondering what sort of backlash one can expect with them. I also haven't priced/sourced them yet - so are cheap ones likely to suffer from more backlash or is servo gearing overall generally tight?

Also noise - when I have seen servo projects, they tended to have pretty loud gearing/motor noise (say compared to non-servo gearhead DC motors) Is that  just a characteristic of all servos or just low(er) end?

tx!

Most hobby servos have pretty low backlash, I don't think you will have a problem with that. As far as noise, several have asked that recently and it's pretty much hit and miss depending on specific servo model used. As it's not a published spec on any servo I recall all I can recommend is you ask around on a R/C forum for peoples experience and recommendation for the quiet servos. http://www.rcgroups.com/forums/index.php

I've seen servos from around $8 to $200 dollares, so quality and capablities have a wide range. The better brand name servos offer specifications that can help is choosing. http://www.hitecrcd.com/products/analog/index.html
10563  Using Arduino / Project Guidance / Re: Turning the arduino on with a relay on: February 26, 2011, 02:39:26 am
Sounds like a simple application. Just get a 5v relay like this maybe: http://www.allelectronics.com/make-a-store/item/RLY-499/5-VDC-SPDT-6A-RELAY/1.html I would wire the relay coil via a spare USB cable, just hack of the end and wire the USB +5vdc and ground wires to the relay coil and plug into your PC. You might want to wire a diode across the coil terminals, anode to the ground wire, cathode to the +5vdc wire, to clamp transients. The six amp contact ratings for that relay should be able to handle just about anything you might have in mind.

Or you could wire the relay coil to a spare internal disk drive power connector's +5vdc and ground pins.


Lefty
10564  Using Arduino / Microcontrollers / Re: Atmega32L Arduino Bootloader installed! And working arduino sketch!!! *WHEW!* on: February 26, 2011, 02:22:08 am
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I am still gathering info on what exactly the Arduino bootloader is needed for, but what I do know is you need it for rx/tx functionality for easy uploading of sketches from the ide, but as far as I have known that's about it. I know there is more to it but you can use my method as described and upload without bootloader at all which in turn also gives you the option of writing larger programs.

The bootloader is needed for only one function, to allow the IDE to upload a sketch via AVRDUDE using a serial protocol. Once the sketch is loaded and running the bootloader is not used or required by any of the Arduino core commands or libraries. It is just a way to program a AVR chip without requiring an independent hardware programmer.

 If you already have such a hardware programmer or even a spare arduino board running the ArduinoISP sketch then there is really no reason to burn a bootloader to the chip. It's really a user's choice these days, however as the IDE and arduino boards ship they assume and utilize the bootloader method to upload sketches, and is simpler for first time arduino users to get going with.

Lefty
10565  Using Arduino / Sensors / Re: Multiplexing a Thermocouple Input on: February 26, 2011, 02:04:20 am
Quote
Anyways, I'll be posting the table of R values vs. Temp and my calculated coefficents for the Thermoworks probes in a different thread if anyone else would like to use them.

Great, I'll take mine medium rare, thanks.  smiley-wink


Lefty
10566  Using Arduino / Project Guidance / Re: Geiger counter/Scaler program questions. on: February 26, 2011, 01:54:38 am
Mike I already have signal conditioning circuitry in place to convert the pulses into square waves with the GM-10.

http://www.blackcatsystems.com/GM/products/GM10GeigerCounter.html

For the moment I would be happy to just count pulses to the terminal emulator as I learn my way around the programing.

Thanks.

Tracy

Then basically you just need to look at the various frequency counter sketches that people have developed to see which best meets your present and future needs. It's the same task with just different timebase being used, pulses per min Vs cycles per second. just do a "arduino frequency counter" search and I'm sure lots of sketches will show up.

Lefty


Lefty
10567  Using Arduino / Project Guidance / Re: Using the Arduino to control a 12 volt micro-pump on: February 25, 2011, 11:01:28 pm
The fact that you require 6 output pins for the pump relays and 12 input pins for the switches, that almost maxes out the 20 total I/O pin that a 328 based arduino board offers. That leaves little room for expansion. So you could either start off with a mega board which has 54 I/O pins, or start with a design that utilizes external shields to add I/O pin expansion. Or you could utilize matrix scanned keypads that can save on I/O pin Vs a little more complexity in the software. On surface not really a demanding application, just lots of little details to work out.

 As far as the software side, It looks pretty simple. However I would need to know more about the pump operation. Does just commanding a relay on for a short pulse guarantee the correct amount gets dispensed, or does the relay have to stay on for the whole time period programmed, with the assumption that the pump will always dispense the same amount of material in that fixed time period?

 There is no apparent feedback mechanism shown in your block diagram for actually measuring the product being delivered. What you show is called 'open loop' control where you make assumptions that parts of the system will always operate correctly and consistently given the same commands at the same specific time periods. A 'Closed loop' control system would include feedback measurements that might in this case be measuring the actual flow of material or weight the product being added. These 'process' measurements also allow warning alarms or automatic shutdown based on actual measurement Vs expected behaviour.

Bottom line is I think the Arduino platform will work just fine for your application. It's just a matter of details being researched, hardware build and sketch developed. Go for it.  smiley-cool

Lefty
10568  Using Arduino / Project Guidance / Re: Powering my Arduino Uno Project on: February 25, 2011, 10:39:59 pm
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Kind of like people, I guess. Easier to talk than listen.


That is rather a mystery. Plus throw in the fact the evolution gave us two ears but just one mouth and we have a real mystery there.  smiley-wink
10569  Using Arduino / Motors, Mechanics, and Power / Re: Servo definition problem on: February 25, 2011, 10:00:44 pm
You just create more servo objects like:

#include <Servo.h> // import servo control functions
Servo myservo1; // create servo object #1
Servo myservo2; // create servo object #2
Servo myservo3; // create servo object #3


//create boolean variables to store the values of the 2 switches
boolean switchValue1;
boolean switchValue2;
void setup() {
pinMode(3, INPUT);
pinMode(7, INPUT);
myservo1.attach(9);
myservo2.attach(10);
myservo3.attach(11);

And so on. That make sense?

Lefty


10570  Using Arduino / Microcontrollers / Re: uC doesn't boot on stripboard, no idea why on: February 25, 2011, 09:56:23 pm
 If you have a scope or can borrow the use of one, the next thing I would do is see if the crystal is actually oscillation by putting the scope probe on chip pin # 10. If you have a bad crystal or using the wrong size caps chip won't do a thing.


Lefty
10571  Using Arduino / Audio / Re: Crummy Digitizing on: February 25, 2011, 07:48:32 pm
Without a lot of external support components and modules, I think an Arduino is a poor choice for processing/sampling audio signals via A/D conversion. Not saying it can't be done in some manner, but it's like trying to fit a 2 pound application into a 1 pound arduino.  smiley-wink

10572  Using Arduino / Microcontrollers / Re: uC doesn't boot on stripboard, no idea why on: February 25, 2011, 07:44:22 pm
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but the only one relevant to the microcontroller is the led-resistor series that goes from arduino digital pin 13 to 12 (physical pin 19 to 18).

To blink a led/resistor string with the blink program it should wire from arduino digital pin 13 (physical pin 19) and ground. Why would you wire the other end to arduino pin 12? And of course the led must be wired in the correct direction.

Lefty


10573  Development / Suggestions for the Arduino Project / Re: LAY-OUT OF THE In-Out PINS on: February 25, 2011, 07:33:18 pm
And the lack of a easy to enable/disable automatic board reset via DTR signal. Over complex/designed auto voltage switching Vs simple manual switch or jumper.

All these have been discussed forever on this forum, so it's a bit old in the tooth. Plus one can always choose 3rd party boards that correct or improve some or all these 'problem areas'. Still all in all the Arduino platform has seemed to have become the dominate hobbyist platform at this time inspite all it's 'flaws', so many of us have tired of the subject and have moved on.  smiley-wink

Not sure I'm too impressed with the new Uno board with all it's various bootloader bugs to date, ceramic resonator Vs crystal, SMD Uno model without the removable 328 chip, but then again I don't have to buy one do I?


Lefty
10574  Using Arduino / Microcontrollers / Re: beginner (research stage) questions on: February 25, 2011, 06:37:28 pm
Quote
So basically the Uno Board has a bootloader that allows you to load sketches into the Boards microcontroller, ArduinoISP sketch turnes the Uno into a the programmer and the blank microcontroller is wired up from the protoboard to the Uno Board to allow Studio to program the blank chip including burning the appropriate bootloader on the new chip.

No, all the various bootloader files are in the Arduino IDE core files on your PC. When you select burn bootloader from the IDE, it uses the proper bootloader file determined by what board you have selected in the Arduino IDE. Then you select burn bootloader, you have to select a hardware programmer type, which can be any arduino board that has already been prior loaded with the arduinoISP sketch. Then some wiring has to be done from the arduino board to the breadboard mounted blank avr chip. So then the Arduino IDE talks to the arduino board (acting like a hardware programmer) that talks to the blank chip. Nothing in this chain of events uses AVR Studio and I'm pretty sure that you can only use 'real' hardware programmers with AVR Studio. Getting Arduino stuff working well in AVR Studio is a pretty complex topic, some may have done it, most have problems with all the gory details. I use only the Arduino IDE platform when doing stuff with Arduino boards and chips.

Keep in mind you may be mixing up two different topics, 1. burning a bootloader into a blank chip and 2. uploading a sketch into a standalone AVR chip which contains the Arduino bootloader. Both steps are required but they are separate tasks that use different steps. Once your standalone chip has a bootloader all that you need to upload sketches from your PC to the standalone chip is to hold the Uno chip in reset with a wire jumper and then wire the pin0 and pin1 serial data to your standalone chips serial data pins, then just upload from the IDE after selecting the correct chip (board type) in the IDE.

Lefty


10575  Using Arduino / Programming Questions / Re: Arduino board resets after Switch...Case? on: February 25, 2011, 04:39:46 pm
So I get that I'm pulling too much power via USB to supply all the servos properly, hence it cutting out. Is there a way to boost the power while its on USB?

Also, every time I plug this in, all the servos power up, and it stands up. Is this right, or do I have a mixed wire somewhere?

All the servos red wires (+5vdc) need to be connected to a independent power source, not the arduino board, not USB power.
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