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1  Using Arduino / Project Guidance / Re: Arduino thermostat safety on: April 12, 2014, 10:26:35 am
Seems as if the connection between your wireless sensor and the Arduino may not be very reliable. In order to understand why that is you'd need to know what the communication mechanism was, whether it was suitable for the way you're trying to use it and whether it was being used correctly.

The wireless sensor is fine. It's a purchased one. Most of the time the Arduino receives the temperature, just sometimes it appearantly doesn't.

Now that I think about it, it might be an error in the code. Could you check it for me?
Code:
unsigned long maxMillis = 1200000; // if the last temperature measurement was over 20 minutes (in milliseconds) ago, consider it unreliable and switch to the second thermostat.
unsigned long lastMillis = 4293767291; // millis() at the time of the last temperature measurement.

void thermostat(){
    if((millis() - lastMillis) > maxMillis){
      therm_override = false; //Consider the temperature measurement inaccurate, and fall back to following the other.
    }else{
      if(targetTemp - lastTemp >= tempOffset){
        digitalWrite(outputPin, heatOn);
        heating = true;
      }else{
        digitalWrite(outputPin, !heatOn);
        heating = false;
      }
    }
}
lastmillis is updated to millis() when the Arduino receives a temperature.
2  Using Arduino / Project Guidance / Arduino thermostat safety on: April 12, 2014, 09:05:55 am
I'm building a web-connected Arduino thermostat that goes between the central heating unit and our ordinary thermostat. By default it imitates the normal room thermostat, but an override can be enabled so that the Arduino will control the room temperature on its own.

The Arduino receives the temperature from a wireless sensor that sends out the temperature and humidity every minute. The Arduino keeps track of the last time it has received the temperature. If this is over 5 minutes ago, it considers the last temperature measurement unreliable and turns off the override (switches back to the normal room thermostat).

I've been having the problem that the Arduino tends to switch off the override by itself a lot. I've already increased the 'reliability' time from 5 to 20 minutes.

Could you think of a better security measure? I don't want the room freezing or getting too hot.

I can't hook up a wired temperature sensor, as the Arduino is not located in the living room.
3  Development / Other Hardware Development / Re: Leonardo clone circuit check on: August 23, 2013, 02:02:51 am
So my schematic should be okay now?
4  Development / Other Hardware Development / Re: Leonardo clone circuit check on: August 22, 2013, 07:17:01 am
I've updated the schematic, how does this look?
5  Development / Other Hardware Development / Re: Leonardo clone circuit check on: August 21, 2013, 04:08:18 pm
But wouldn't the (small) voltage drop affect some components/shields? I'd like to be as close to 5V as possible, with as little components as possible.
6  Development / Other Hardware Development / Re: Leonardo clone circuit check on: August 21, 2013, 03:16:37 pm
CrossRoads, how would I seperate the USB and regulator power?

And there are 0.1uF caps on the 5V and VIN line
7  Development / Other Hardware Development / Re: Leonardo clone circuit check on: August 21, 2013, 02:37:20 pm
That would be useful, thanks
8  Development / Other Hardware Development / Re: Leonardo clone circuit check on: August 21, 2013, 02:07:50 pm
Thanks, I'll get on it  smiley
9  Development / Other Hardware Development / Leonardo clone circuit check on: August 19, 2013, 02:38:40 am
Would anyone mind checking the schematic for my new arduino leonardo-compatible board? I'm particularly concerned about the USB power.
10  Using Arduino / Microcontrollers / Re: 2 MCUs sharing pins on: July 01, 2013, 06:36:53 am
diodes on the PWM outputs from each Arduino.
That was my first solution as well, but I don't want to cut traces on the second arduino (etched a special board for it) so I can't access those lines.
11  Using Arduino / Microcontrollers / 2 MCUs sharing pins on: July 01, 2013, 04:48:50 am
Here's my situation:

I have one RGB led controller with a Red, Green and Blue input for PWM.
These RGB connections are shared between Arduino's.
Only one of them is powered via the 5V at the time, but sometimes the other one seems to be receiving power via the RGB pins and takes over. How do I solve this problem?
12  Using Arduino / General Electronics / Re: LED different voltage resistor value on: June 28, 2013, 07:48:12 am
I don't believe in  47 Ohm  @ ( 12 V - 2*1.3 V ) This would give 190 mA, far beyond the max 50 mA.

Me neither, but it's really what the kit designer used: http://www.velleman.eu/downloads/0/minikits/manuals/manual_mk162.pdf

Maybe they chose it because since it's an IR remote the IR LED's will only go on for a very short while
13  Using Arduino / General Electronics / LED different voltage resistor value on: June 28, 2013, 07:14:34 am
Okay, so here's the deal:

I've got two unknown LED's connected in series to a 12V source via a 47 Ohm resistor.
Now I would like to power them off 5V, how would I calculate the proper resistor value?

Edit: found the type of LED: http://www.soselectronic.com/a_info/resource/pdf/king/l-934f3bt.pdf

14  Community / Exhibition / Gallery / Re: WiFi Spectrum Analyzer on: September 27, 2012, 07:26:52 am
Hi folks,

I was looking to build a 2.4GHz analyser and I stumbled upon this thread. Thankyou for your hard work and I would like to share a couple of changes I have made which allowed me to increase the fast scan scanning speed by a wopping 54.5 times!

Could i have your complete modified code?
15  Using Arduino / General Electronics / Re: Calculating LED current on: September 09, 2012, 03:57:13 am
Oh ok, thanks!
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