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1  Using Arduino / Networking, Protocols, and Devices / Is it possible to have a bidirectional arduino connection with one wire? on: April 06, 2014, 07:42:03 am
Is it possible to have a bidirectional Arduino connection with one wire; in a single-master multi-slave configuration ?
Assuming all of them share the same 5V and ground lines.
2  Using Arduino / Project Guidance / Re: Capacitve touch stability on: December 21, 2013, 02:41:15 pm
Probably - an Arduino.

The Arduino is the least likely to be a critical part of your setup.

My suspicion would be - your plastic panel.  Acrylic ("Perspex")?  Is its surround grounded as well as the Arduino?  What is the environment?  Air conditioning?

As always, the actual circuit you are employing and a photograph of your setup would be useful if we were to look for clues.

Sorry for the late reply but we got hit by a severe snow storm and had to stop working on my projects.
Here is the circuit:



The red wires go to the foil and the yellow ones control two servos.
Digital Pin 9 is the "send pin" and Pins 4 through 8 are "Receive pins"
I used 10M resistors and tried using 120pF and 22pF and 330pF capacitors , I didn't notice much difference in the performance.
also tried removing all capacitors the system went unstable then and sensitivity dropped horribly!

The Arduino is inside a water cooler. The cooler is earthed and so is the Arduino.
I am not sure what kind of plastic the panel is but it a 3 mm  thick.
a photo of the setup :





3  Using Arduino / Motors, Mechanics, and Power / Re: Unable to drive two servos simultaneously on: December 21, 2013, 01:30:50 pm
Sorry for the late reply but we got hit by a severe snow storm and had to stop working on my projects.
Anyway this is how everything is connected:

Terminals 1 through 4 are VCC, Ground, digital pin 11 and digital pin 3 respectively.
The servos are MG995.
The 5V is coming from a DC adapter with 1A max.

I  got a multimeter with a "fast max" mode that can read current spikes, it showed a maximum reading of 2.1 Amps !!
And Arduino resets then. A single servo draws about 1.7A when it starts and more than 2A when it overshoots. But settles on 0.2~0.3 A.
So yes, it brownout as you mentioned.

I am thinking of replacing the servos with smaller ones.
But until I get them replaced how can I solve this problem?
I believe using two supplies one for Arduino and another for the servos would solve it. but is there a better solution?
Like can I limit the current they are drawing or something similar to that?
(I don't have any large capacitors right now to put across the supply and can you explain how that helps?)
And one more question, if I installed another supply for the Arduino and let the servos operate on the 1A one? is that dangerous? can they damage the supply since they will draw >1A current at some point.
4  Using Arduino / Project Guidance / Capacitve touch stability on: December 07, 2013, 04:17:55 am
Hi, I am using this library :
http://playground.arduino.cc//Main/CapacitiveSensor?from=Main.CapSense
to control 4 touch keys beneath a plastic panel to drive some servos.
I ran through some noise issues which I solved with grounding the arduino and adding some capacitors as suggested in the article.

But still it is not very reliable for something permanent! Sometimes the servos are turned on without anyone in the room!
I tried using different sampling rates and different methods from the library but still it is not very stable!

So what do you recommend for a stable capacitive-sensing chip that is easy to implement with arduino?
5  Using Arduino / Motors, Mechanics, and Power / Re: Unable to drive two servos simultaneously on: December 07, 2013, 03:59:11 am
Power the servos from a pack of four AAs and don't forget to connect the grounds together.
The grounds are connected.
But why to use AA batteries ? the servos are installed inside a device and I am gonna use them almost daily. so I don't want to keep changing batteries, what is wrong with source I am using or how can I detect if there is a problem?
at first I thought they might need more current but when I checked with an ammeter and they only use 0.2 A max !
6  Using Arduino / Motors, Mechanics, and Power / Unable to drive two servos simultaneously on: December 07, 2013, 03:47:23 am
I have two MG995 servos connected to a mini arduino-compatible board with a Atmega328p on it.
the problem I am facing is that I cannot move the two servos together!
whenever I do this
Code:
servo1.write(40);
servo2.write(40);
the board resets and the servos go crazy!
I have to move the first one the first to 40 degrees then back to 0
then do the same with the other one.
I am powering the servos and the arduino from a 5v dc adapter with max 2A DC load

7  Using Arduino / Microcontrollers / Re: ATTiny85. IDE responds:"Invalid device signature, define PAGEL and BS2 signals" on: October 07, 2013, 03:10:20 pm
I just tried the other chip(0612) and it worked even though I tried programming it before!!
The blink sketch is working perfectly on it. I put back the (0548) chip and still it is not working, I checked the resistance between the vcc and gnd for both of them it is around 7.7 megs
could it be that sth wen wrong with fuses of the other chip ?
8  Using Arduino / Microcontrollers / Re: ATTiny85. IDE responds:"Invalid device signature, define PAGEL and BS2 signals" on: October 07, 2013, 08:11:55 am
The Atmel logo looks wrong to me, the lines in the logo are far too thick and the rightmost of the two vertical lines in the 'm' doesn't go all the way to the top.

The writing is also far too white (that's what called my attention in the first place). I always had trouble getting the writing on Atmel chips to appear at all in photographs but yours is as clear as day. Notice that you can't read the writing on the Uno's ATMega328 in your first photograph - that's what I'd expect to see from that distance/angle.

The date codes are a bit weird. You say you bought them ten months ago but the date codes say 2005/2006.

All in all ... I'd say there's a good chance they're fakes. There might be nothing at all inside the chips.

Don't worry, it's happened to people like Sparkfun, too: https://www.sparkfun.com/news/350

How can I make sure that they are fake ?
9  Using Arduino / Microcontrollers / Re: ATTiny85. IDE responds:"Invalid device signature, define PAGEL and BS2 signals" on: October 07, 2013, 08:11:06 am
I normally use Opera but I have also looked at this Thread in Firefox and there is no sign of any images from LDavinci.

But it appears some people can see them. If you are one of the lucky ones, what browser are you using?

...R
I think it is the server that I uploaded the photos to.
here are they on imageShack
The setup :
http://imageshack.us/photo/my-images/837/ihbt.jpg/
ATTiny Close-up:
http://imageshack.us/photo/my-images/580/uis3.jpg/
10  Using Arduino / Microcontrollers / Re: ATTiny85. IDE responds:"Invalid device signature, define PAGEL and BS2 signals" on: October 07, 2013, 05:17:17 am

Are these chips new? Is there any way they could have been programmed before?

Where are they from? The markings on the chip in that image don't look like my Tiny85s. Can you post a close-up of the chip?

Yes they are new. I got them from eBay 10 months ago, but never used them before.
Here is a close up.
11  Using Arduino / Microcontrollers / Re: ATTiny85. IDE responds: "please define PAGEL and BS2 signals" on: October 06, 2013, 02:50:59 pm
well here is an image of the setup

on the upper arm of the Arduino the (yellow,green,blow,red) are connected to (13,12,11,10)
on the lower part (red,orange,white) are (reset,5V,GND)
I did a continuity check on from the legs of the ATTiny to arduino, and also checked the voltage, and changed the bread-board just now.
12  Using Arduino / Microcontrollers / Re: ATTiny85. IDE responds: "please define PAGEL and BS2 signals" on: October 06, 2013, 02:01:57 pm
It could mean that you have incorrectly programmed the fuses so that it requires an external oscillator. If you are using ArduinoISP, you can modify the sketch to output an 8MHz square wave from one of the PWM pins which you can then feed in to the XTAL1 pin of the attiny.

Add these lines to the setup() of ArduinoISP:
Code:
  pinMode(3,OUTPUT);
  TCCR2A = _BV(COM2B0) | _BV(WGM21);
  TCNT2 = 0;
  OCR2A = 0;
  TIMSK2 = 0;
  TCCR2B = _BV(CS20);

Then connect Digital Pin 3 of the Arduino to Pin2 of the Attiny85.
same result :/
13  Using Arduino / Microcontrollers / Re: ATTiny85. IDE responds: "please define PAGEL and BS2 signals" on: October 06, 2013, 01:35:52 pm
avrdude: Device signature = 0xffffff
avrdude: Yikes!  Invalid device signature.

0xffffff means bad wiring - it hasn't managed to get a real device signature off the chip.

I checked the resistance between the pins of the ATTiny and the ends of the jumpers that are in the Arduino.
I also used a different set of jumpers, different board, different chip. No luck at all ~_~
14  Using Arduino / Microcontrollers / Re: ATTiny85. IDE responds: "please define PAGEL and BS2 signals" on: October 06, 2013, 12:36:59 pm
Tried 1 Mhz still not working..
15  Using Arduino / Microcontrollers / Re: ATTiny85. IDE responds: "please define PAGEL and BS2 signals" on: October 06, 2013, 12:22:41 pm
I just used a different Arduino board, still the same result.
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