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121  Using Arduino / Installation & Troubleshooting / Re: Uno R3 Serial stuck to 9600 on: October 25, 2012, 09:37:48 am
change the serial monitor to 115200baud, close and reopen it
This might be a stupid answer, but be sure to close the serial monitor then change the baud rate , that will automatically reboot your arduino.
122  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 25, 2012, 09:27:18 am
Hello!

What you really want to know, is "are these batteries able to run my project, if I need them to?".
Exactly! smiley-wink

However, as far as I know, the only reason why the batteries cannot supply enough power, is that they have too less voltage.
And this can be checked with reading their voltage.
So if the V_batt is enough (say 7V) then they can supply power for everything, otherwise they cannot.
This is how I would say, the batteries work like. Even if I don't know much about this, neither about the chemistry of them.
123  Using Arduino / Installation & Troubleshooting / Re: Uno R3 Serial stuck to 9600 on: October 25, 2012, 04:54:18 am
you must select the same baudrate in serial.begin (xxx )  and in the serial monitor
124  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 24, 2012, 03:55:46 pm
I don't understand why I should check the batteries with load.
Increasing the resistor values will decrease the current drawn. And the only thing I want to check is whether the batteries are still able to work as a power source if they are needed.
I think this is what I was told here to pay attention to.
And sorry if I don't understand you in the right way, I am still new to this...
125  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 24, 2012, 01:16:07 pm
Can it be approximated with 2000mAh/0.82mA = 2440h (even if the relation is not really linear how the graph shows)
126  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 24, 2012, 12:29:18 pm
Hello.

Now I think about a way of not having any switch:
And if I have an always current flowing though the voltage divider and the analog input, what do you think, how much current is drawn?
Additionally, I am interested in the way of how to calculate the current drawn and the estimated life using what the battery says about its mAh ...
So, assuming R3=10K, R4=1K. Higher resistor values decrease the current drawn, AFAIK.
Battery full = 9V, i.e. 9V*1K/(10K+1K)=9V/11 =0.8V (analogRead = 164)
But how to calculate the current drawn ??
For calculation assume capacity Q=2000mAh, and current drawn: I = 50mA, then I think time: t=Q/I=2000mAh/50mA=40h (that would be bad, it is not even two days)

( I had an idea with a relay. )
127  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 24, 2012, 12:07:25 pm
And if I have an always current flowing though the voltage divider and the analog input, what do you think, how much current is drawn?
Additionally, I am interested in the way of how to calculate the current drawn and the estimated life using what the battery says about its mAh ...
So, assuming R3=10K, R4=1K. Higher resistor values decrease the current drawn, AFAIK.
Battery full = 9V, i.e. 9V*1K/(10K+1K)=9V/11 =0.8V (analogRead = 164)
But how to calculate the current drawn ??


128  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 24, 2012, 07:03:09 am
Ok now I understand.

so you might have to use larger values for R3 and R4
This goes for R1 and R2, too?

And I changed the resistance values of R3, R4.
However, I think if D5 is not GND, then 9V goes straight to A1 which is not good because it is limited to 5V. Dangerous?
If D5 is GND then I understand how it works, is digitalWrite(5,LOW) really the same as attaching something to GND?
I attached the schematics like I understood it.
129  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 23, 2012, 05:43:55 am
You could make the ground leg of the voltage divider be an Arduino output pin.  Make it low to assert ground, take your A2D measurement, then make it an input and write a 0 to it, to turn off the pull-up.  It should not sink much current in this state.
The measurement is from the voltage divider (battery's 9V pole) to A1, and the switch is controlled by a relais, so that there isn't always current flowing.
What is the "ground leg of the voltage divider"? Do you just mean ground?


And what do you think about this idea (schematics)?
130  International / Deutsch / Re: Arduino Mega on: October 22, 2012, 11:38:56 am
Aha, habe dazu z.B. hier was gefunden.

Aber könnte ich einen Ausgang auch als integer-Variable definieren, und dann mit digitalWrite arbeiten?
Wie ich jetzt gesehen habe, brauch der 74HC164 drei Eingänge und hat acht Ausgänge, also sozusagen 5 Pins zusätzlich.
Könnte man dann die acht Ausgänge z.B. 31,32,33,34,35,36,37,38 nennen und dann z.B. mit pinMode(33, OUTPUT) ihn als Ausgang definieren?
Und kann der Schieberegister genauso als digitaler Aus- wie Eingang benutzt werden?
Und gibt es auch die Möglichkeit, analoge Signale zu senden (PWM) oder zu lesen?
131  International / Deutsch / Re: Arduino Mega on: October 22, 2012, 11:13:20 am
Danke für die Antworten!
Ich werde zunächst bei meinem Uno bleiben (habe ja schon zwei), allein weil ein Arduino recht teuer ist.
Von Shiftregistern habe ich schon gehört, mich damit aber noch nicht befasst. Dann habe ich wohl was zu tun smiley-wink
Sehe ich das richtig, dass man sie dann genauso benutzen kann wie einen digitalen oder sogar analogen Ein-/Ausgangs-Pin?
Problematisch wird das bei z.B. dem LCD, der ja in der Library als Klasse definiert ist, dessen constructor ja "integer"pins erwartet. Kann man die von den Shiftregistern auch irgendwie als integer zuweisen und dann als Paramter diesem constructor übergeben?
132  International / Deutsch / Arduino Mega on: October 22, 2012, 10:04:17 am
Hallo,

da ich langfristig mehr Pins brauche, denke ich den Mega zu holen.
Ist denn der Arduino Mega einfach nur wie der Uno nur mit mehr Pins, hat also keine Nachteile und alles kompatibel und die Pins sind übereinander? Das heißt, z.B. der Pin 5 vom Uno ist an der selben Stelle wie der Pin 5 beim Mega? Dann wären ja alle Shields schonmal kompatibel.

Und ich meine jeweils die neusten Modelle
Arduino Mega 2560 R3
Arduino Uno R3

Vielen Dank
133  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 22, 2012, 07:17:41 am
something like this, I meant

Code:
digitalWrite(5, HIGH); // close the circuit, now A1 gets battery voltage
delay(500);  // give relais some time
int measure_voltage = analogRead(A1);  // now read the voltage

And...
voltage divider  factor  =  220/1220 = 0.18
Battery full: 9V; 9V *0.18 = 1.62V; 1.62V *1023/5V = 331 (=measure_voltage)
Now map(0,331,0,1000) (ca. multiply with 3, but there is an arduino function called map) and get 0.1% steps (promille) of battery voltage
Code:
int battery_voltage = map(measure_voltage,0,331,0,1000)

What do you think, good idea?
134  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 22, 2012, 05:47:57 am
Ah now I understand the problem: The batteries need to be controlled so that they work when they are needed - so that you can rely on them.
 However, I don't understand how you want to use the relais exactly.
Maybe a voltage divider can be attached to the battery and then the analog reading - exactly like I have drawn it near the wall-wart power supply. Additionally, a relais can be used to switch reading battery voltage and then to open it again. This can happen via a digital output once in a minute,e.g.
135  Using Arduino / Project Guidance / Re: rechargable batteries for uninterruptible power supply on: October 21, 2012, 05:05:52 pm
sooner or later the battery
voltage will not be able to reliable act as a
standby source
sorry ,but I don't get what you mean
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