In my project I am using a 9V battery so I can read and compare the voltage to lower threshold value which is normally 5V (operation voltage level typically for Arduino). So if the voltage goes lower 5.00V it should activate theoretically rescue 5V battery.
V1: 9V Battery
VCC-Arduino output pin#8 (5V to trigger up IRLU014)
R1 and R2: voltage divider=4.90 Output
V2: 5Vbattery 1350mAh
It looks like great on multisim everything is working perfectly. I am not sure how good is it in real life…
/*************************************************************************
VOLTAGE DIVIDER R2(1.220kOhm)-GND R1(1.000kOhm)+9V V2=V1*(R1+R2)/R2
/************************************************************************/
const int BATpin=A2;
float BATVoltDiv=0;
float BATVoltInit=0;
int samples=15;
void setup(){
/********************************************************
BAT PIN CONFIGURATION
/********************************************************/
pinMode(BATpin, INPUT);
}
if(analogRead(BATpin)>0){
for(int i=0; i<=samples; i++){
BATVoltDiv=analogRead(BATpin)*5.00/1024;
BATVoltInit=BATVoltDiv*(1.000+1.220)/1.000-1.45; //Correction 1.45
}
}
To describe briefly Arduino application (it set’s via bluetooth Time with RTC module, and transmits voltage from a 9V battery, Time, Electromagnetic Field from both antennas, and able to activate another battery 5V if 9V gets < 5.00V - here I am).
Wawa:
~2k2 across a 9volt battery (4mA) will drain it in less than 4days.
Leo..
No-no this is not a question I have a rescue battery connected as the same that can be activated when a voltage drop is above the limit 5.00V.
I rode that RAW is about 7-12V is that people saying, In my case, I am using Arduino mini pro 5V (very happy with that: works pretty stable with majority of modules). I tested 5V on RAW pin and it works as well. I able to detect bluetooth module with my cellphone, not with my computer. But it's already something : ))
I notices an interesting fact that the USB battery rescue pack (works with cellphone Samsung) is shutting down its power port to absolute 0V (I think that its due to small current output 40mA which should be close to 1A as specifications says). It works for I wile and suddenly 0V. Is there any way to make this battery work a "little bit longer" - I mean for the rest of the time.
Not sure what you mean here, but maybe this person's experience demonstrates the concept better
pmhassin
I have had two of these things fail on me in the last few weeks. I have mine connected to 5.2 V on the RAW pin. It works fine for awhile, then the Arduino just go bad. Anyone else have this problem????!!!
kevink
You’re going to need more than 5.2V for the RAW pin. The RAW pin uses a regulator, which has a dropout voltage of ~1.7V. This means the board is only getting 3.5V, which is not enough. If you have to use the 5.2V supply I would suggest you get the 3.3V version.
Another option would be to regulate to 5V outside of the board and connect to any VCC pin.
I think that its due to small current output 40mA which should be close to 1A as specifications says
the spec means that up to 1A may be safely drawn from it. with only 40 mA it should last much longer. as far as why it would suddenly go to 0v sounds like it may be defective.
Thank you Hutkikz! That took me a while to figure out how to connect the Rescue battery, because it's refusing to work after some seconds (as you said due to small output current which is 40mA on VCC pin). And I learned here that we can't use 5.2V on RAW pin. I figured out how to satisfy the battery and the board at the same time, so I connected the rescue battery on VCC and RAW pin and I noticed that current increased to 100mA at 100mA the battery is not trying to shutting down.
