Show Posts
Pages: 1 [2] 3 4 ... 173
16  Using Arduino / General Electronics / Re: ganging transistors, ~3a dc motor controller on: September 13, 2014, 04:44:21 pm
"Ganging" junction transistors, of whatever stripe, is not a good idea.  (I guess I better add "IMO").
"Ganging" outputs on ULN2803s is OK because they are on the same die. (That will not help the OP.)
Junction transistors are depicted on ICs as "ganged", but, again, they're on the same die.
"Ganging" discrete FETs is acceptable.
Different situations.

I see that someone points out that El OP did mention heatsinking, afterall.
I'd like to see a picture of it.
If it's a little tab-mounted fin job, then forget it.

I think that all of these thorny power electronics considerations can be dispensed with by using a relay.
17  Using Arduino / General Electronics / Re: 3v Laser Power design, and why did they all suddenly blow out? on: September 13, 2014, 04:27:17 pm
Im sure they all have resistors pre soldered onto them. I think Mikes suggestion seems the most probable to me.

I'm the one saying that they're prepped (have resistors etc.), ready to go, guy.

What suggestion?

I'm telling you that I've run them from batteries and a power supply, same 25mA each, 3 in parallel for 78mA.

Ive ordered new, any precautions? i dont want to burn another lot...

a) Watch your wallet, Caveat emptor
b) Light a candle
18  Using Arduino / General Electronics / Re: 3v Laser Power design, and why did they all suddenly blow out? on: September 13, 2014, 01:42:18 pm
I'm sorry, but I have a few of these guys here.
They're prepped "modules".
Maybe mine is/are different.
I use them with batteries (2X AAA).
I disconnected one and put it on the milliammeter, 25mA, same with the batteries or the power supply and it's all across the device.
Just relating based on my experience.

Maybe malik's device is different.

> > > I dug up three others that I had still.  In parallel, 78mA.  As a bonus, everybody gets a close-up of my grotty keyboard.
19  Using Arduino / General Electronics / Re: 3v Laser Power design, and why did they all suddenly blow out? on: September 13, 2014, 01:14:35 pm
Those are just pointer modules.
They don't need anything extra.

Oh im sorry, correction, i connect exactly 8 of them in Parallel. Individually they performed perfectly.

How many do you have (left)?  2 ?

It's a good thing that we probably don't have a milliammeter (DMM) so we can go on with guessing games into 50 pages
20  Using Arduino / Motors, Mechanics, and Power / Re: Which h bridge circuit is more suitable for my dc motor. on: September 13, 2014, 01:03:24 pm
Guys, could we please not fight?
delay (1000);
     smiley-lol

Oh, that was good.
I thought I could post that without laughing, but I could not.

Well, here's the rest of the circuit.
It's rudimentary for sure.
Shoot-through and other concerns can be addressed in software (no slamming from FWD to REV, no having FWD Hi  and REV pwm going at the same time, stuff like that.)  

> > > "newbie" isn't designing, he's trawling for others to do that, like it's a piece of cake. Well, that's all for me till Jimmy Doce starts par-ti-ci-pa-ting.

> > > changed the placement of the darlingtons' base resistors (better now.)
21  Using Arduino / General Electronics / Re: 3v Laser Power design, and why did they all suddenly blow out? on: September 13, 2014, 12:29:14 pm
So i connected about 8 of them in parallel to a 3v supply,...

Its just when i connected them in series. Its very odd as all of them dimmed at the same time and died.

First you posted that you connected "about 8" (about means 7, 8, maybe 9) "in parallel".
Then you had them "in series".
Oh my.
Very odd, indeed.
I feel that I need to ask you to confirm the difference (in a drawing.)

They passed the individual 5-6 minute test.
How about the two in parallel 5-6 minute test?
22  Using Arduino / General Electronics / Re: 3v Laser Power design, and why did they all suddenly blow out? on: September 13, 2014, 11:25:09 am
Maybe they're junk.
Maybe they're not for "constant duty", hours on end operation.
Maybe something else.
23  Using Arduino / Motors, Mechanics, and Power / Re: Which h bridge circuit is more suitable for my dc motor. on: September 13, 2014, 09:23:49 am
I have to use the BDV66B and BVD67B.

Those alone won't be enough.
Other components are necessary.
I've attached a "half-bridge."

> > > adding dwg w/ 2 control inputs, omitting previous w/ only 1

> > > changed place of darlington base resistor (disregard previous)

Are we learning anything?
If so, then what?
24  Using Arduino / General Electronics / Re: ganging transistors, ~3a dc motor controller on: September 13, 2014, 07:46:57 am
If it's a only matter of turning a "tomato stirring motor" on for several hours then you should use a relay.
Pretty simple.
Industry has been using them for years and still.

> > >  You didn't mention adequate heatsinking for your TIP-xxx transistors. (Probably "None", right?)
25  Using Arduino / Programming Questions / Re: Reading digital pins on: September 11, 2014, 09:02:15 pm
Works the same, but you'll have to dig up and look at the datasheet

http://www.atmel.com/Images/Atmel-2549-8-bit-AVR-Microcontroller-ATmega640-1280-1281-2560-2561_datasheet.pdf

to see which pins are associated with which ports.
26  Using Arduino / Programming Questions / Re: RS232 Sound Module on: September 11, 2014, 08:57:23 pm
You need to have
Serial.begin(9600);
in your setup()

Serial.write("p+");
Serial.print("p+");
will knock out a p and a +

Arduino doesn't have "true" and "inverted" baudmodes.
27  Using Arduino / Microcontrollers / Re: Something wrong with ATTiny85 and its 2 PWM outputs on: September 11, 2014, 08:48:25 pm
ATtiny85 processors have three Arduino compatible PWM pins.

1) D0 (IC pin 5)
2) D1 (IC pin 6)
and
3) is on which?

> > > >
seeker,
I can't make out your wiring from your video.
A photo would be best.
28  Using Arduino / Programming Questions / Re: Reading digital pins on: September 11, 2014, 08:42:47 pm
Yes, look into Port Manipulation.

http://playground.arduino.cc/Learning/PortManipulation

> > > The paradigm here emphasizes the digitalRead(), speed, and building a function to gather all that up with.
29  Using Arduino / Motors, Mechanics, and Power / Re: DIY motor driver h bridge on: September 11, 2014, 08:37:59 pm
Why did you start another subject on this matter?

http://forum.arduino.cc/index.php?PHPSESSID=k3ten7dp4bn2eq585tok07jed5&topic=264793.0

30  Using Arduino / LEDs and Multiplexing / Re: TLC5958 on: September 09, 2014, 08:08:24 pm
when I tried in the past to get TI chips that were not at Digikey those samples requests never came through.  I would like a few of these.

Maybe they've become more circumspect about who gets samples or what for.
So, you might need a letterhead or a good story for the samples.
[Unlimited top-side then, shall it be?]
Pages: 1 [2] 3 4 ... 173