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1  Topics / Science and Measurement / Re: Removing DC offset from differential amplifier on: June 26, 2013, 11:23:39 am
Almost resolved:

The AREF was not grounded... Now the offset is ~134.

Still not ideal! But better
2  Topics / Science and Measurement / Removing DC offset from differential amplifier on: June 26, 2013, 10:50:06 am
Hi all,

I am running a differential amplifier (AD620 from texas instruments) to amplify signals from a load cell in some weighing scales.

I want to optimise the system by utilising all 10bits of ADC of the ardiuno capabilities.

At rest position the DC offset reads at approximately 300 (roughly 1.6V, wasted resolution)

Is it possibly to  remove this offset (1.6V) from my signal without compromising in resolution?

Obviously I can divide the voltage off the signal before it hits my Arduino but then I would loose 1.6V of resolution at the top end of the ADC. (As my amplifier and Arduino is running at the same voltage)

I could run my amplifier chip at 1.6V greater than my arduino (it can take it) to give a 10bit resolution with a 0V dc rest.

I'm hoping a simple rewire to the signal wires instead.

Any guidance would be great,

Thanks.
3  Topics / Home Automation and Networked Objects / Re: WiFi.config() - Static IP problem - RESOLVED on: June 23, 2013, 11:53:17 am
The WiFi.config() now works after:

1. Downloading and using Arduino 1.0.5.
2. Firmware updated following Arduinos instructions:
http://arduino.cc/en/Hacking/WiFiShieldFirmwareUpgrading

I found the Arduino instructions to be rather non-intuitive, especially if you are not friendly with command prompt.

Basically to upgrade the firmware on the shield you have to:
1. Upgrade HDG104 named "wifi_dnld.elf"
2. Upgrade T32UC3 named "wifiHD.elf"

I used this tutorial to help with a non command prompt update method:
http://www.dfrobot.com/community/how-to-upgrade-arduino-wifi-shield-firmware-on-windows.html

I hope this helps anyone with similar problems.
4  Using Arduino / Project Guidance / Re: Having trouble setting a static IP Address on wifi shield on: June 23, 2013, 09:15:37 am
Similar post/solution:

http://forum.arduino.cc/index.php?topic=173510.msg1289555#msg1289555
5  Topics / Home Automation and Networked Objects / Re: WiFi.config() - Static IP problem on: June 23, 2013, 09:13:04 am
Thanks John,

I have installed 1.0.5 and was able to call and upload WiFi.config(ip).

Despite this it does not set a static IP, rather a dynamic one, as the next available on the network.

I will look into the firmware.

6  Topics / Home Automation and Networked Objects / WiFi.config() - Static IP problem - RESOLVED on: June 22, 2013, 03:03:16 pm
Hi all,

I am trying to make my arduino wifi shield gain a static ip on my network using the example:
http://arduino.cc/en/Reference/WiFiConfig

Example code:
Code:
#include <SPI.h>
#include <WiFi.h>

// the IP address for the shield:
IPAddress ip(192, 168, 0, 177);    

char ssid[] = "yourNetwork";    // your network SSID (name)
char pass[] = "secretPassword"; // your network password (use for WPA, or use as key for WEP)

int status = WL_IDLE_STATUS;

void setup()
{  
  // Initialize serial and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present");
    while(true);  // don't continue
  }

  WiFi.config(ip);

  // attempt to connect to Wifi network:
  while ( status != WL_CONNECTED) {
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:    
    status = WiFi.begin(ssid, pass);

    // wait 10 seconds for connection:
    delay(10000);
  }

  // print your WiFi shield's IP address:
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());
}

void loop () {}

When I do this, I have the error of:

 'class WifiClass' has no member named 'config'

I have updated the wifi library, there is probably something simple I am doing wrong but I have read some discrepancy in the capabilities of the static IP feature of the arduino wifi board.

Does anyone know why I am getting this error?
Has anyone had any experience in doing this?

Thanks,
7  Using Arduino / Networking, Protocols, and Devices / Re: Wifi Connection on: June 19, 2013, 06:04:22 pm
Is you arduino shield assigned to the same network as your PC? (Are both devices connected to the same network)

Sadly I have made this mistake more than once
8  Using Arduino / Networking, Protocols, and Devices / Re: Wifi only connects when connected to Arduino with serial monitor. on: June 19, 2013, 05:55:32 pm
Have you updated to the latest firmware version?
9  Topics / Home Automation and Networked Objects / Re: Can i remote control an Android from an Arduino ? on: June 19, 2013, 05:50:01 pm
Why do you need external sensors (on top of Android camera) to sense a person?

Why don't you just use the camera to look for differences in the picture... If there is a significant difference in the camera footage then film or capture.
10  Using Arduino / Networking, Protocols, and Devices / Re: WiFi Shield R3 - Issues Connecting on: June 07, 2013, 10:06:27 pm
is the WiFi board properly mounted onto the uno? all pins connected?
11  Using Arduino / Networking, Protocols, and Devices / Re: WiFi.RSSI(); Not updating? on: June 07, 2013, 09:55:43 pm
Has anyone had any luck in sorting this? (after a firmware update)
12  Using Arduino / Networking, Protocols, and Devices / Re: LED fade over bluetooth on: June 07, 2013, 09:54:01 pm
Can you post the arduino code?

have you considered using a bluetooth hyperterminal such as Blueterm from a mobile phone type device?
13  Topics / Home Automation and Networked Objects / Re: Arduino Wifi-shield freeze on: June 07, 2013, 12:22:44 pm
Hi,

can you post the source code? or is it a arduino example.

previous firmware versions did have a connection drop out problem.

you said you have updated the firmware. have you updated to the latest firmware?
14  Using Arduino / Networking, Protocols, and Devices / Re: WiFi.RSSI(); Not updating? on: January 05, 2013, 10:24:18 am
The RSSI read does not update as i change physical locations from my router.

For example, the signal displayed in the serial monitor, from this code, does not change/update as i move a large distance away from the router (eg. 3 bricked rooms).

Code:
void loop() {
  long rssi = WiFi.RSSI();
  Serial.print("signal strength (RSSI):");
  Serial.print(rssi);
  Serial.println(" dBm");
  delay(500);
}

But when i manually reset my board and wait for a reconnection the RSSI updates to a new value, to a more realistic value.

I'm assuming the program I have written does not tell the wifi board to make a new reading?


In response too:
Quote
Besides wishing, what are you doing?
I am wishing that the kind arduino community might be able to point out my error :-).

Thanks for your time PaulS.
15  Using Arduino / Networking, Protocols, and Devices / Re: WiFi.RSSI(); Not updating? on: January 05, 2013, 10:07:04 am
Quote
You might want to put a second or so delay in the rssi reading loop,

I have tried this and I still see no update.

If i reposition the wifi sheild further away from the router it does show a signal change if i manually restart the board.

I still cannot get the RSSI read to update within the program.
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