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31  Using Arduino / Sensors / Re: TMP36 Brownout possibley killed it on: December 12, 2012, 01:27:43 am
usually the datasheets say a "absolute maximum voltage"...

what if u disonnect that TMP36 and connect it to 3V and measure its output then?
32  Using Arduino / Sensors / Re: SD data logging stops (8x8 matrix) on: December 12, 2012, 01:13:08 am
Hi!

What if u dont open the SD file and just print the result to the serial port?

Why do u read just 7 of those 8 analog pins?

Have fun...
33  Using Arduino / Sensors / Re: DHT22 Can i share the data pin ?? on: December 09, 2012, 01:15:43 am
hi!

u could use 2 devices that communicate with that DHT22,
if u can make sure, that they dont try that at the same time... smiley
that 1-wire protocol doesnt tolerate communication collisions...

u could try to do it like ethernet does it:
1. carrier sense: a unit, that wants to talk, looks at the line for some time in order to c if communication is going on right now...
2. collision detect: a talking unit reads the line during a write request in order to c if someone "overwrites" its communication...

have fun...
34  Using Arduino / Sensors / Re: ADS1234 : 24bits load cell adc on: November 27, 2012, 06:21:06 pm
maybe something gets stuck in the chip during power up?

what if u reset the chip after power up by pulling down pin 26 (-PDWN) and then up again?
35  Using Arduino / Sensors / Re: Why did I melt my LM35DZ? on: November 27, 2012, 06:13:14 pm
hi!

can u show us a picture?
and the sketch?

i use many LM35 and they never get hot...

i say:
1.
either the polarity is wrong (5V/GND swapped)
2.
or u configured the A0 pin as output...

have fun...
36  Using Arduino / Sensors / Re: Can I connect capacitive touch sensors to Pin 0 or 1? on: November 19, 2012, 09:31:39 am
yup - digitalRead(14) works...
analog pin 0 is also a digital pin...
37  Using Arduino / Sensors / Re: Can I connect capacitive touch sensors to Pin 0 or 1? on: November 19, 2012, 01:21:31 am
Hi!

If u need to do Serial communication, u cant use pin 0 or pin 1.

But u can use digital pins 2 to 13 (=12 pins) and analog pins 0 to 5 (=6 pins numbered digital pins 14 to 19)...  smiley

Bye
38  Using Arduino / Sensors / Re: arduino ATtiny85 on: November 14, 2012, 01:16:20 am
Hi!

I use some ATtiny85-s for the same purpose, too...
But I connect them via one data cable with the  central...
The central pulls it high when it wants to talk to someone...
Then it calibrates the 1-bit (e. g. 20usec low) and the 0-bit (e. g. 10usec low)...
Then it sends the address of the ATtiny85 it wants to talk to...
Then it sends the request including a parity byte...
Then the ATtiny85 starts talking by pulling down the line...

U need less cables and less hardware, but it still works... smiley

Bye
39  Using Arduino / Sensors / Re: Increasing sensitivity of a simple resistive touch sensor on: November 13, 2012, 04:18:05 pm
ok
with a transistor (e. g. a npn bjt like 2N4401 (IIRC)) u should get better results...
in darlington configuration it should b even better...
http://www.pcbheaven.com/circuitpages/Resistance_Touch_Button/

i use a self made touch key keyboard when lying in bed and it works quite reliable...
just when i spill juice on it, it behaves funny...
i covered the electrodes with duct tape...
and i use one capacitance multiplier (or what i believe it is) for each key:
http://en.wikipedia.org/wiki/Capacitance_multiplier
40  Using Arduino / Sensors / Re: Increasing sensitivity of a simple resistive touch sensor on: November 13, 2012, 01:14:44 am
Hi!

Maybe a darlington config?
http://en.wikipedia.org/wiki/Darlington_transistor

can u give us a drawing of ur circuit?

Have u seen this?
http://www.arduino.cc/playground/Code/CapacitiveSensor

Bye
41  Using Arduino / Sensors / Re: Wires from a sensor on a fully rotational servo on: November 11, 2012, 08:46:26 am
this seems to b 1 method to do it:
http://en.wikipedia.org/wiki/Slip_ring

they claim to b better:
http://www.mercotac.com/html/faqs.html#q1  smiley
(but they r not RoHS compliant because they use mercury...  smiley-red)
42  Using Arduino / Sensors / Re: Questions about piezos. on: November 09, 2012, 11:17:56 am
*wag tail*

PS: if u want u may try the "Modify" icon above ur posting... smiley
43  Using Arduino / Sensors / Re: Ohm Meter Issue on: November 08, 2012, 06:18:08 pm
Quote
Ok so if I set Vref to 5v and instead of a 10K known resistance I have say a 3.3K would that work?
yup - sure - it's kirchoff's law... no electron ever violates it...  smiley
http://en.wikipedia.org/wiki/Kirchoff%27s_circuit_laws
44  Using Arduino / Sensors / Re: Questions about piezos. on: November 08, 2012, 06:13:24 pm
the sharp raising edge should b easy to detect...

if the reading jumps in a short time (e. g. between two readings) by 1 stripe, u can b sure that it is a tap...
after a tap u can just stop detection for some time...

like this:
Code:
void loop() {
  uint16_t lst=0;
  for (;;) {
    const uint16_t now = analogRead(x);
    if (now>lst && now-lst>thresh) {
      Serial.print(millis());
      Serial.printtln("TAP");
      delay(100); // no more than 10 taps/second?
    }
    lst=now;
  }
}
?
45  Using Arduino / Sensors / Re: Questions about piezos. on: November 08, 2012, 01:51:39 am
Hi!

can u make a picture of the response with an oscilloscope?
maybe the arduino can b the oscilloscope by do a lot of
Code:
Serial.println(analogRead(x));
?

Have fun
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