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1  Using Arduino / Motors, Mechanics, and Power / Re: How Many amps does this transformer output? on: August 23, 2014, 12:29:43 am
Also don't forget base resistor between the arduino and transistor. Otherwise you risk damaging the arduino pin.
2  Using Arduino / Motors, Mechanics, and Power / Re: How Many amps does this transformer output? on: August 23, 2014, 12:21:00 am
Those " arduino motor drivers" are typically very inefficient and require considerable heat sinking in order to get close to their rated output. Do you have  info or datasheet on your driver?
3  Using Arduino / Motors, Mechanics, and Power / Re: How Many amps does this transformer output? on: August 22, 2014, 01:11:54 pm
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, the power from the controller blew through them and they did not work 
what does this mean? Did the transistor blow up? How was it connected? A Schematic and or picture would help. Which transistor? 1 amp is cutting it a little close. DC motors have high start up current. Are you using a heatsink?
4  Using Arduino / Motors, Mechanics, and Power / Re: How Many amps does this transformer output? on: August 22, 2014, 11:02:23 am
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Why is listed as VA instead of W ?
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Because transformers work off AC and va is the units for ac power. It is convention... basically. In this situation, it is safe to assume that VA roughly equals watts in rms. Power factor is really only an important consideration in industry and large scale power distribution where efficient power transfer is crucial. i have never needed to calculate power factor for any of the small projects I have built.
5  Using Arduino / Motors, Mechanics, and Power / Re: How Many amps does this transformer output? on: August 21, 2014, 09:36:09 pm
Theory aside...The transistor selection depends on whether you want to control AC or DC currents. AC currents require a triac (BTA136 perhaps) or scr and usually an optocoupler driver (MOC4031) for isolating ac an dc. The common way for controlling dc is to use a logic level mosFET.
6  Using Arduino / Motors, Mechanics, and Power / Re: How Many amps does this transformer output? on: August 21, 2014, 09:04:26 pm
Also the current rating is an indication of how much current you can draw without causing excessive voltage drop or overheating the transformer. You can usually draw more current at the cost of losing voltage. So simply shorting the transformer out with an ammeter is not the best indicator of how much current it  can reasonably produce. You really need to increase the load while monitoring current and voltage because open circuit voltage is significantly higher then short circuit voltage (or rather overcurrent).
7  Using Arduino / Motors, Mechanics, and Power / Re: How Many amps does this transformer output? on: August 21, 2014, 08:48:11 pm
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incandesent lights have filaments, which makes them inductive.
I disagree. Incandescents are practically entirely resistive. Power factor is a negligible consideration for small appliances  under normal operating conditions. However, people have been known to do some illogical things. IF you are using it for its intended purpose, it should be ok. Given the 7.5va rating I would estimate it should be capable of .5 amps. Hard to say though since it's a dual voltage supply and only gives one power rating, so you can only assume it's a combined rating.
8  Using Arduino / General Electronics / Re: Arduino Motor Shield - Voltage Supply on: August 19, 2014, 01:30:44 pm
The mega has an automatic voltage selecting circuit that should only allow it to be powered from one source at a time . I would have to look at the schematic to be sure, but I think the barrel plug takes precedence over usb.
9  Using Arduino / General Electronics / Re: Does a LM7809 help me boost arduino uno's 5V to 9V? on: August 16, 2014, 05:39:30 pm
Dc - dc boost converters like xl6009 or lm2577 will take 5v and boost it up to 9v ( with the help of additional components). This type of converter can easily draw several amps depending on what it powers, which would burn up the arduino. Running it directly from the arduino is ill advised, but  it should work if you power from an external 5v source. Can you explain in detail what you trying to do? Check Google for info on buck - boost converters or Switched Mode Power Supplies smps.
10  Using Arduino / Motors, Mechanics, and Power / Re: help with motor project on: August 06, 2014, 07:49:56 pm
you might do something like:  digitalread ForwardButtonPin.  if it is high, analogread PotPin and map the analogvalue to functional rpm speed of your motor, and set the stepper stepping. Repeat for ReverseButtonPin. This approach might look something like this:
Code:
byte forward = digitalRead(ForwardButton);
if (forward == HIGH)
{
 // read the analog in value:
  sensorValue = analogRead(PotPin);           
  // map it to the range of the motor speed:
  rpm = map(sensorValue, 0, 1023, 0, 255);  // change 255 to the top speed of your mootr
 
  myStepper.setSpeed(rpm); //set the rpm speed
  myStepper.step(stepsPerRevolution/100); //move a few steps forward
}
byte reverse = digitalRead(ReverseButton);
if (reverse == HIGH)
{
 // read the analog in value:
  sensorValue = analogRead(PotPin);           
  // map it to the range of the motor speed:
  rpm = map(sensorValue, 0, 1023, 0, 255);  // change 255 to the top speed of your motor
  // change the analog out value:
  myStepper.setSpeed(rpm); //set the rpm speed
  myStepper.step(-stepsPerRevolution/100); //move a few steps backward
}
i'll let you define the appropriate variables as you see fit
11  Using Arduino / Motors, Mechanics, and Power / Re: Powering Neopixels and Arduino board from one adapter on: July 30, 2014, 02:06:20 pm
Vin provides power to the input side the voltage regulator which regulates the voltage from the Vin pin down to 5volts on the output side which is also connected to the 5v pin. Vin and the barrel plug are basically the same and require 7-12volts. To run the v.reg. The notable exception is that there is a protection diode connected between Vin and the plug. So the barrel plug has reverse polarity protection, but Vin does not because it is after the diode.
12  Using Arduino / General Electronics / Re: How will moisture affect an Arduino? Rain? on: July 29, 2014, 09:04:56 pm
Humidity is probably OK, but excessive condensation could cause problems.
13  Using Arduino / Motors, Mechanics, and Power / Re: help with motor project on: July 29, 2014, 08:51:07 pm
I did understand, and yes you did ask how to connect it. No, i wont write your code for you, (but someone else might). However, everything you need to know is in the arduino IDE, and any specific questions you might have we would be happy to answer for you. Yes, someone will help you with your code, but you first have to post whatever code you have even if it is just the example sketch and be specific with your questions. 1)Start with the example sketch and get your motor moving, 2) once you know the example code works, add a button input. 3) if you run into problems report back here and post your code.
14  Using Arduino / Motors, Mechanics, and Power / Re: help with motor project on: July 26, 2014, 06:17:39 pm
i would say start by doing some homework.
1)make sure you know how stepper motors work and what type yours is exactly.
2) look up the datasheet for the uln2803 and make sure it can handle the current drawn by the motor. the datasheet will usually provide you  with enough info to connect it up.
3) learn to use the arduino. work through the examples in the IDE under Basics, Digital, analog, control and stepper. "stepper" should have most of the code you need, the rest you can probably just cut and paste .
15  Using Arduino / Motors, Mechanics, and Power / Re: help with motor project on: July 25, 2014, 11:26:12 am
What questions do you have? Show your code. How do you plan to wire it up? Show a schematic. You could do this with just one potentiometer. When the pot is in the center, the motor is stationary. As you twist the pot off center the motor will spin faster one way or the other.
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