Show Posts
Pages: 1 2 [3] 4 5 ... 147
31  Using Arduino / General Electronics / Re: can anybody tell me the gain of this transistor for 0.15 amp collector current? on: April 12, 2014, 10:36:34 am
What are you trying to do?
Be specific.
32  Using Arduino / Project Guidance / Re: logic for arduino programming? on: April 12, 2014, 10:34:52 am
Could be at the beginning of your loop, digitalRead for a switch and you'd go to one function or another from there.
Even then, from either function you could check that switch to go to the other function.
33  Using Arduino / Project Guidance / Re: Arduino GPS speed pulse generator for digital speedometer on: April 12, 2014, 09:25:22 am
Well, if it's a 21 inch radius then the circumference is 132 inches = 3.35 metres.
2 * 3.14159 * 21 = 132 in   132 in * 2.54cm = 335 cm = 3.35 m
100 km/h / 60 / 60 = 27.78 m/s (metres per second)
27.78 / 3.35 = 8.29 revolutions / sec  [8.3 Hz]
34  Using Arduino / General Electronics / Re: How to use shift register. on: April 09, 2014, 09:03:45 pm
Some shift registers are for inputs and others are for outputs.
A 74_165 is used to shift the states of its inputs to the device that controls it.
35  Using Arduino / Programming Questions / Re: Arduino Uno as a HID Keyboard PROBLEM on: April 09, 2014, 01:30:37 pm
You do NOT want to increment the counter when the pin IS low. You want to increment when the pin BECOMES low. Look at the state change detection example.

so Why it should not be counted when its low?

PaulS was drawing your attention to the difference between a transition from HIGH to LOW vs. a LOW state.
36  Using Arduino / LEDs and Multiplexing / Re: Send LED HIGH after "x" seconds on: April 07, 2014, 09:19:26 pm
I don't know which is the active state of a PIR sensor .
My assumption, for this sketch, was that it would go Low.
You can change that easily.

Anyway, once the 5 consecutive second threshold is crossed, LED 13 goes On.
And it stays on till the Reset button is pushed or you include a separate reset option

Code:
//  trippoint5sec
//
//  wait for 5 seconds
//  of constant detection
//

unsigned long refTime;
unsigned long trippoint;
const long threshold = 5000;
byte DET;
const byte pirPin = 8;
const byte ledPin = 13;

void setup ()
{
  //pirPin is INPUT by default, use ExtPullup
  pinMode (ledPin,OUTPUT);
  digitalWrite (ledPin,LOW);
}

void loop ()
{
  DET = digitalRead(pirPin);
  if (DET == 1)  // inactive
  {
    refTime = millis();
    trippoint = refTime;
  }
  else   // Active Low
  {
    pir_active();
  }
}

void pir_active ()
{
  trippoint = millis();
  if ((trippoint-refTime) > threshold)
  {
    digitalWrite(ledPin,HIGH);
  }
}
37  Using Arduino / Project Guidance / Re: How to connect an 8ohm speaker to an Uno? on: April 05, 2014, 12:20:46 pm
... or keep it "low key"
http://www.radioshack.com/product/index.jsp?productId=2103254
38  Using Arduino / LEDs and Multiplexing / Re: Flicker on outputs of 2 of 4 shift registers-TPIC6B595 driving LEDs on: April 04, 2014, 12:03:07 pm
Some breadboard power rails don't have continuity all the way through, from one end to the other.
They can be split.
You might want to check yours.
39  Using Arduino / LEDs and Multiplexing / Re: TTL BCD-7 Segment display driver IC, problem on: April 03, 2014, 08:16:27 am
Get a 4511 (CD4511, et al.) or a different display.
40  Using Arduino / General Electronics / Re: Help, arduino 5volts not enought on: April 02, 2014, 08:14:50 am
The Nano's 5V doesn't have the capacity of the Uno.
A couple of 100mA fans?
And an MP3 sound module?
You'll have to arrange supplementary power.
41  Using Arduino / Project Guidance / Re: Powering Externally While Reading Serial on: March 31, 2014, 09:16:35 pm
What a worthless forum this is. I came here asking a legit question, I was respectful, and everyone just wants to give me blatently wrong information or be a complete prick. Good luck with that shit.

Blatently wrong?

Replies #1 and #6 gave correct answers to your "question".
Is there a dispute?

42  Using Arduino / Project Guidance / Re: Powering Externally While Reading Serial on: March 30, 2014, 07:17:44 pm
I'm trying to figure out if I can power up the Micro from the motorcycle at the same time I've got the Micro hooked to the USB port on my computer so that I can read the serial data to troubleshoot an issue I'm having. ...

You may.

http://arduino.cc/en/uploads/Main/Arduino_Uno_Rev3-schematic.pdf
43  Using Arduino / Project Guidance / Re: Arduino GPS speed pulse generator for digital speedometer on: March 30, 2014, 05:40:06 pm
Radius of 21'' wheel in front (21'' * 2.54 *3.14) - 1.6748m... Which is 16.6Hz right ?

radius (r) is the distance from centre to the outside, (diameter (d) is twice that
circumference = 2 * pi * r
44  Using Arduino / General Electronics / Re: BNC Connections on: March 30, 2014, 11:58:20 am
I cannot resist.
If you bought a pair of shoes that didn't fit, would whatever kind of laces they had have anything to do with it?
45  Using Arduino / Project Guidance / Re: Arduino GPS speed pulse generator for digital speedometer on: March 30, 2014, 09:56:24 am
my hall sensor generates 1.65pps at 100km/h  (21in wheel - 1 pulse per wheel turn)

No way.
Show your math.
Pages: 1 2 [3] 4 5 ... 147