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1  Using Arduino / Motors, Mechanics, and Power / Stepper drivers in parallel on: April 04, 2014, 05:36:00 pm
I have a Nema 23 stepper motor I would like to drive at about 2A, is it possible to wire two 1A stepstick drivers in parallel to do so?
2  Using Arduino / General Electronics / Triacs VS relays on: March 11, 2014, 07:12:06 pm
On ebay I see a lot of single relay boards, 8 channel relay boards, optocoupled relay boards, and so on, but I never see any triac boards. I recently had a project with solenoid valves, but switching them with relays made my LCD display go all wonkey, so I used a (bt139) triac instead. After this everything worked fine.

Why aren't triacs used more widely?  (It isn't particularly expensive, for a triac + optocoupler is only about 2 dollars.)
|s there a big disadvantage I don't know of?
3  Using Arduino / Motors, Mechanics, and Power / Re: NEMA17 H-bridge? on: January 15, 2014, 05:54:17 pm
Too bad, I'll get myself a driver then.

Thank you very much!
4  Using Arduino / Motors, Mechanics, and Power / Re: NEMA17 H-bridge? on: January 15, 2014, 08:36:04 am
I do have some small unipolar steppers, but they are way too slow to move a curtain nicely, so that won't work well..

As last try at making my own driver, would it be an idea to PWM a 12v supply at about 5%, 32Khz, and use that as power input in the H-bridge? This would effictively give me about 0.4A on the stepper.

Or am I just way better off buying a A4988 driver? All it has to do is spin though, there's not a lot of force..
5  Using Arduino / Motors, Mechanics, and Power / NEMA17 H-bridge? on: January 15, 2014, 08:01:59 am
I wanted to open and close my curtains with a nema17 stepper I have laying around, so I built two simple H-bridges out of DB139 and DB140 transistors.

But then I measured the resistance of the two coils in the stepper motor; 1.5 Ohms.

Driving this with 5 volts would mean a current of about 3 Amps, which seems retardedly high. But I use the steppers in my reprap aswell, where they are driven with 12v.

What do the stepper controllers from the reprap do so that the steppers work on 12v without burning out, and how would I build a simple driver for this myself?
6  Using Arduino / Programming Questions / Re: Software SPI.transfer on: January 12, 2014, 02:45:55 pm
It took a while, but I ended up writing it myself!
At first replacing the function didn't work at all, but that ended up being because the SPI was still "on", so I couldn't write to the 13 and 11 pins myself..

Here's the code:

Code:
uint8_t softSpiTransfer(uint8_t shOut){
  uint8_t shIn = 0;
  for(int i = 0; i < 8; i++) {
    if (shOut > 127)  digitalWrite (outPin,1);
    else              digitalWrite (outPin,0);
    if (digitalRead(inPin)) shIn += 1;
    digitalWrite (clkPin,1);
    digitalWrite (clkPin,0);
    if (i != 7) shIn <<= 1;
    shOut <<= 1;
  }
  return shIn;
}
7  Using Arduino / Programming Questions / Re: Software SPI.transfer on: January 12, 2014, 10:43:22 am
I'm softwarePWMing the 24 LED channels. This has te be done pretty fast, so this will need the hardwareSPI. I know it can be done the other way around, but the leds need 4096 bytes shifted out every time there will be one message coming on the nrf24 module. I also have an other light that just uses the 6 arduino PWM pins, so for that i'd also have to clear pin 11.

What do you mean with "Something else like the nrf24?" ?
8  Using Arduino / Programming Questions / Re: Software SPI.transfer on: January 12, 2014, 10:01:42 am
What is your reason for avoiding the hardware SPI?

I've got a big bunch of sound reactive lights, but it's a pain to run jack cables to all of them, so I'd like to broadcast the 'decoded' audio to all lights at once via nrf24l01+ modules.

One of the lights:


The lights however use the shiftPWM library, which uses the hardware SPI aswell.

In the MIRF library for the nrf24l01+ modules, sending and receiving is all done with the SPI.transfer function.
I'm looking for a function to replace that function, but using softwareSPI.
9  Using Arduino / Programming Questions / Re: Software SPI.transfer on: January 12, 2014, 08:58:29 am
Yes, I know, but just shifting out a byte doesn't get you a received byte..
10  Using Arduino / Programming Questions / Re: Software SPI.transfer on: January 12, 2014, 08:04:47 am
This justs shifts the data out right? I'm looking for the SPI.Transfer function, but without the hardware SPI pins. The transfer function returns a received byte aswell.
11  Using Arduino / Programming Questions / Software SPI.transfer (Solved!) on: January 12, 2014, 06:14:11 am
I was wondering it there is a software version of the SPI.transfer function from the SPI.h library.

I know of the shiftout and shiftin functions, but you can't just use them both to simulate the transfer function..

Is there something like this available anywhere?
12  Using Arduino / Installation & Troubleshooting / Re: Leonardo keyboard/mouse control not working on: January 05, 2014, 10:23:03 am
Although I wasn't using a USB HUB or something similar, changing the USB port seemed to do the trick.
13  Using Arduino / Installation & Troubleshooting / Re: Leonardo keyboard/mouse control not working on: January 05, 2014, 10:01:02 am
Well, if I just plug it into my laptop it works fine. So I guess it's a driver issue? I have never manualy installed the drivers there though..
Could anyone help me with this?
14  Using Arduino / Installation & Troubleshooting / Leonardo keyboard/mouse control not working on: January 05, 2014, 09:24:52 am
I recently got myself an arduino leonardo, which for the biggest part works without any problems. I did have to change a file in order to install the drivers (which is described here http://forum.arduino.cc/index.php?topic=108231.15).

But now I want to use it to control my mouse, but it doesn't seem to be able to control anything.

The code I last used was:

Code:
void setup() {
  Keyboard.begin();
}

void loop() {
  Keyboard.write('u');
  delay(1000);
}

It doesn't work at all though, the mouse commands do not work either..

What could cause this problem?

Edit: The "TX" light does light up when it should be typing keys.
15  Using Arduino / Programming Questions / Re: Comma instead of semicolon on: January 04, 2014, 11:27:20 am
Code:
Code:
if(button) { toggle = 1; led = 1; }
does the same thing, correctly.

The arduino auto-format wipes this out to:
Code:
if(button){
  toggle = 1;
  led = 1;
}
again, and I really like to use that..

Anyway, I looked up the it's function like you said, and there I found:

Avoid a block
For brevity, the comma can be used to avoid a block and associated braces, as in:
Code:
if (x == 1) y = 2, z = 3;
if (x == 1)
    y = 2, z = 3;

instead of:
Code:
if (x == 1) {y = 2; z = 3;}
if (x == 1) {
    y = 2; z = 3;
}

So that's the contrary of what you said, but it does answer my question..
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