💬 Battery Powered Sensors

[Nicklas Starkel]

Sorry, where do you measure the power when it is in sleep mode? ie, where do you put your multimeter probes.

[mfalkvidd]

@Nicklas-Starkel you put them in serial. So:
battery+ to multimeter- (set to uA mode)
Multimeter+ to vcc
Battery- to gnd

You need a very sensitive multimeter though. Most multimeters won't be able to measure low current reliably.

[Nicklas Starkel]

@mfalkvidd that's what I thought! I see that I'm getting 3.4V in the multimeter but my pro mini nor nano will start up (I have not removed the LEDs so they should light up).
If I use more V (6.8V) I put in via RAW on the PRO mini, and I can see teh voltage, but the same thing, it's not starting up, hmmm I wonder what rookie mistake I'm doing!

[mfalkvidd]

@Nicklas-Starkel sounds like you have the multimeter set to measure voltage instead of current. Which multimeter model are you using? Could you post a photo? There is usually a dial that can be turned to switch mode. Many multimeters also require moving one of the probes to a different connector (on the multimeter itself).

[Nicklas Starkel]

@mfalkvidd , it was too late at night for me.
I had it at current but it didn't show anything. So without thinking I put it at voltage.
And the problem with not showing anything when I had it at current was I had blown the internal multimeter fuse some days ago.
Ehrmm.. yes. move along, nothing to see here :)

[mfalkvidd]

@Nicklas-Starkel great that you figured out what was wrong

[bjacobt]

Hi, I built this circuit and arduino reads 1.11 V or 33%. I've new batteries and multimeter reads 3.10 volts. Do you know what could be wrong? I'm using 1M and 470k resistors on pin A0.

[tonnerre33]

Hello,

Did you put this command in the setup sketch ?

analogReference(INTERNAL);

[bjacobt]

@tonnerre33, yes I've analogReference(INTERNAL); in setup()

[tonnerre33]

It's normal to have 1.1V on A0 when you have 3.3V on your batteries.

Where did you get the 1.11V value ? In the serial print or with your multimeter ?
If you read the value with the serial print, which variable is it (sensorValue or batteryV) ?

[bjacobt]

@tonnerre33 in the serial print and MySensor MQTT gateway

[bjacobt]

@tonnerre33, I'm trying to build arduio that can run on 2 AA batteries. I'm using MySensors for library and building arduino circuit based on this https://openhomeautomation.net/arduino-battery/

[tonnerre33]

Can you post the logs of your node and the skech used ?

[mfalkvidd]

@bjacobt https://www.mysensors.org/build/battery#measuring-and-reporting-battery-level describes how the battery voltage is calculated and the example sketch has code for doing the calculation. Looks like you've missed reading this part:

   // 1M, 470K divider across battery and using internal ADC ref of 1.1V
   // Sense point is bypassed with 0.1 uF cap to reduce noise at that point
   // ((1e6+470e3)/470e3)*1.1 = Vmax = 3.44 Volts
   // 3.44/1023 = Volts per bit = 0.003363075
...
float batteryV  = sensorValue * 0.003363075;

[bjacobt]

@tonnerre33
Here are the logs from Arduino Serial console

Starting sensor (RNNNA-, 2.0.0)
TSM:INIT
TSM:RADIO:OK
TSP:ASSIGNID:OK (ID=101)
TSM:FPAR
TSP:MSG:SEND 101-101-255-255 s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=bc:
TSP:MSG:READ 0-0-101 s=255,c=3,t=8,pt=1,l=1,sg=0:0
TSP:MSG:FPAR RES (ID=0, dist=0)
TSP:MSG:PAR OK (ID=0, dist=1)
TSM:FPAR:OK
TSM:ID
TSM:CHKID:OK (ID=101)
TSM:UPL
TSP:PING:SEND (dest=0)
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=24,pt=1,l=1,sg=0,ft=0,st=ok:1
TSP:MSG:READ 0-0-101 s=255,c=3,t=25,pt=1,l=1,sg=0:1
TSP:MSG:PONG RECV (hops=1)
TSP:CHKUPL:OK
TSM:UPL:OK
TSM:READY
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=15,pt=6,l=2,sg=0,ft=0,st=ok:0100
!TSP:MSG:SEND 101-101-0-0 s=255,c=0,t=17,pt=0,l=5,sg=0,ft=0,st=fail:2.0.0
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=6,pt=1,l=1,sg=0,ft=1,st=ok:0
TSP:MSG:READ 0-0-101 s=255,c=3,t=15,pt=6,l=2,sg=0:0100
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=11,pt=0,l=13,sg=0,ft=0,st=ok:Battery Meter
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=12,pt=0,l=3,sg=0,ft=0,st=ok:1.0
Request registration...
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=26,pt=1,l=1,sg=0,ft=0,st=ok:2
TSP:MSG:READ 0-0-101 s=255,c=3,t=27,pt=1,l=1,sg=0:1
Node registration=1
Init complete, id=101, parent=0, distance=1, registration=1
330
Battery Voltage: 1.11 V
Battery percent: 33 %
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=0,pt=1,l=1,sg=0,ft=0,st=ok:33

The sketch used is this:

/**
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
 * Copyright (C) 2013-2015 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * DESCRIPTION
 *
 * This is an example that demonstrates how to report the battery level for a sensor
 * Instructions for measuring battery capacity on A0 are available here:
 * http://www.mysensors.org/build/battery
 * 
 */


#define MY_NODE_ID  101

// Enable debug prints to serial monitor
#define MY_DEBUG 

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

#include <MySensors.h>



int BATTERY_SENSE_PIN = A0;  // select the input pin for the battery sense point

unsigned long SLEEP_TIME = 100000;  // sleep time between reads (seconds * 1000 milliseconds)
int oldBatteryPcnt = 0;

void setup()  
{
   // use the 1.1 V internal reference
#if defined(__AVR_ATmega2560__)
   analogReference(INTERNAL1V1);
#else
   analogReference(INTERNAL);
#endif
}

void presentation() {
   // Send the sketch version information to the gateway and Controller
   sendSketchInfo("Battery Meter", "1.0");
}

void loop()
{
   // get the battery Voltage
   int sensorValue = analogRead(BATTERY_SENSE_PIN);
   #ifdef MY_DEBUG
   Serial.println(sensorValue);
   #endif

   // 1M, 470K divider across battery and using internal ADC ref of 1.1V
   // Sense point is bypassed with 0.1 uF cap to reduce noise at that point
   // ((1e6+470e3)/470e3)*1.1 = Vmax = 3.44 Volts
   // 3.44/1023 = Volts per bit = 0.003363075

   int batteryPcnt = sensorValue / 10;

   #ifdef MY_DEBUG
   float batteryV  = sensorValue * 0.003363075;
   Serial.print("Battery Voltage: ");
   Serial.print(batteryV);
   Serial.println(" V");

   Serial.print("Battery percent: ");
   Serial.print(batteryPcnt);
   Serial.println(" %");
   #endif

   if (oldBatteryPcnt != batteryPcnt) {
     // Power up radio after sleep
     sendBatteryLevel(batteryPcnt);
     oldBatteryPcnt = batteryPcnt;
   }
   sleep(SLEEP_TIME);
}```

What I see on the gateway is:

mysGateway: TSF:MSG:READ,101-101-255,s=255,c=3,t=7,pt=0,l=0,sg=0:
mysGateway: TSF:MSG:BC
mysGateway: TSF:MSG:FPAR REQ,ID=101
mysGateway: TSF:PNG:SEND,TO=0
mysGateway: TSF:CKU:OK
mysGateway: TSF:MSG:GWL OK
mysGateway: TSF:MSG:SEND,0-0-101-101,s=255,c=3,t=8,pt=1,l=1,sg=0,ft=0,st=OK:0
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=24,pt=1,l=1,sg=0:1
mysGateway: TSF:MSG:PINGED,ID=101,HP=1
mysGateway: TSF:MSG:SEND,0-0-101-101,s=255,c=3,t=25,pt=1,l=1,sg=0,ft=0,st=OK:1
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=15,pt=6,l=2,sg=0:0100
mysGateway: !TSF:MSG:SEND,0-0-101-101,s=255,c=3,t=15,pt=6,l=2,sg=0,ft=0,st=NACK:0100
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=6,pt=1,l=1,sg=0:0
mysGateway: Sending message on topic: mysensors-out/101/255/3/0/6
mysGateway: TSF:MSG:READ,101-101-255,s=255,c=3,t=7,pt=0,l=0,sg=0:
mysGateway: TSF:MSG:BC
mysGateway: TSF:MSG:FPAR REQ,ID=101
mysGateway: TSF:CKU:OK,FCTRL
mysGateway: TSF:MSG:GWL OK
mysGateway: TSF:MSG:SEND,0-0-101-101,s=255,c=3,t=8,pt=1,l=1,sg=0,ft=0,st=OK:0
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=24,pt=1,l=1,sg=0:1
mysGateway: TSF:MSG:PINGED,ID=101,HP=1
mysGateway: TSF:MSG:SEND,0-0-101-101,s=255,c=3,t=25,pt=1,l=1,sg=0,ft=0,st=OK:1
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=15,pt=6,l=2,sg=0:0100
mysGateway: !TSF:MSG:SEND,0-0-101-101,s=255,c=3,t=15,pt=6,l=2,sg=0,ft=0,st=NACK:0100
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=6,pt=1,l=1,sg=0:0
mysGateway: Sending message on topic: mysensors-out/101/255/3/0/6
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=11,pt=0,l=13,sg=0:Battery Meter
mysGateway: Sending message on topic: mysensors-out/101/255/3/0/11
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=12,pt=0,l=3,sg=0:1.0
mysGateway: Sending message on topic: mysensors-out/101/255/3/0/12
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=26,pt=1,l=1,sg=0:2
mysGateway: TSF:MSG:SEND,0-0-101-101,s=255,c=3,t=27,pt=1,l=1,sg=0,ft=0,st=OK:1
mysGateway: TSF:MSG:READ,101-101-0,s=255,c=3,t=0,pt=1,l=1,sg=0:33
mysGateway: Sending message on topic: mysensors-out/101/255/3/0/0```

Thank for your help!
Jacob

[bjacobt]

hi @mfalkvidd,

Do you mind clarifying a bit, I've done sensorValue * 0.003363075

analogRead(BATTERY_SENSE_PIN);

Gives me 330, so
330 * 0.003363075 = 1.10981475 volts

Thank You!
Jacob

[mfalkvidd]

@bjacobt hmm. Yes, you are correct. The calculation seem a bit strange.
Using this calculator I entered
output 1.10981475 V
R1 1000000
R2 470000
Which gives a battery voltage of 3.471V

Looks like the calculations in the sketch are wrong? Or at least confusing :) I'm pretty lost.

[tonnerre33]

analogRead(BATTERY_SENSE_PIN);

must give you 1023 and not 330.
For me it's a problem of value resistance or analogReference.

Try to add this

analogReference(INTERNAL);
sensorValue = analogRead(BATTERY_SENSE_PIN);
  #ifdef MY_DEBUG
 Serial.print("Value A0 before force reference: ");
 Serial.print(sensorValue);
#endif
delay(10000);
sensorValue = analogRead(BATTERY_SENSE_PIN);
  #ifdef MY_DEBUG
 Serial.print("Value A0 after force reference: ");
 Serial.print(sensorValue);
#endif

Just after this existing code :

   #ifdef MY_DEBUG
   Serial.println(sensorValue);
   #endif

And plz send me the logs of the node ;)

[bjacobt]

@tonnerre33 Its still the same

Starting sensor (RNNNA-, 2.0.0)
TSM:INIT
TSM:RADIO:OK
TSP:ASSIGNID:OK (ID=101)
TSM:FPAR
TSP:MSG:SEND 101-101-255-255 s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=bc:
TSP:MSG:READ 0-0-101 s=255,c=3,t=8,pt=1,l=1,sg=0:0
TSP:MSG:FPAR RES (ID=0, dist=0)
TSP:MSG:PAR OK (ID=0, dist=1)
TSM:FPAR:OK
TSM:ID
TSM:CHKID:OK (ID=101)
TSM:UPL
TSP:PING:SEND (dest=0)
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=24,pt=1,l=1,sg=0,ft=0,st=ok:1
TSP:MSG:READ 0-0-101 s=255,c=3,t=25,pt=1,l=1,sg=0:1
TSP:MSG:PONG RECV (hops=1)
TSP:CHKUPL:OK
TSM:UPL:OK
TSM:READY
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=15,pt=6,l=2,sg=0,ft=0,st=ok:0100
TSP:MSG:SEND 101-101-0-0 s=255,c=0,t=17,pt=0,l=5,sg=0,ft=0,st=ok:2.0.0
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=6,pt=1,l=1,sg=0,ft=0,st=ok:0
TSP:MSG:READ 0-0-101 s=255,c=3,t=15,pt=6,l=2,sg=0:0100
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=11,pt=0,l=13,sg=0,ft=0,st=ok:Battery Meter
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=12,pt=0,l=3,sg=0,ft=0,st=ok:1.0
Request registration...
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=26,pt=1,l=1,sg=0,ft=0,st=ok:2
TSP:MSG:READ 0-0-101 s=255,c=3,t=27,pt=1,l=1,sg=0:1
Node registration=1
Init complete, id=101, parent=0, distance=1, registration=1
330
Value A0 before force reference: 327
Value A0 after force reference: 329
Battery Voltage: 1.11 V
Battery percent: 32 %
TSP:MSG:SEND 101-101-0-0 s=255,c=3,t=0,pt=1,l=1,sg=0,ft=0,st=ok:32

/**
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
 * Copyright (C) 2013-2015 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * DESCRIPTION
 *
 * This is an example that demonstrates how to report the battery level for a sensor
 * Instructions for measuring battery capacity on A0 are available here:
 * http://www.mysensors.org/build/battery
 * 
 */


#define MY_NODE_ID  101

// Enable debug prints to serial monitor
#define MY_DEBUG 

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

#include <MySensors.h>



int BATTERY_SENSE_PIN = A0;  // select the input pin for the battery sense point

unsigned long SLEEP_TIME = 100000;  // sleep time between reads (seconds * 1000 milliseconds)
int oldBatteryPcnt = 0;

void setup()  
{
   // use the 1.1 V internal reference
#if defined(__AVR_ATmega2560__)
   analogReference(INTERNAL1V1);
#else
   analogReference(INTERNAL);
#endif
}

void presentation() {
   // Send the sketch version information to the gateway and Controller
   sendSketchInfo("Battery Meter", "1.0");
}

void loop()
{
   // get the battery Voltage
   int sensorValue = analogRead(BATTERY_SENSE_PIN);
   #ifdef MY_DEBUG
   Serial.println(sensorValue);
   #endif

analogReference(INTERNAL);
sensorValue = analogRead(BATTERY_SENSE_PIN);
  #ifdef MY_DEBUG
 Serial.print("Value A0 before force reference: ");
 Serial.println(sensorValue);
#endif
delay(10000);
sensorValue = analogRead(BATTERY_SENSE_PIN);
  #ifdef MY_DEBUG
 Serial.print("Value A0 after force reference: ");
 Serial.println(sensorValue);
#endif
   

   // 1M, 470K divider across battery and using internal ADC ref of 1.1V
   // Sense point is bypassed with 0.1 uF cap to reduce noise at that point
   // ((1e6+470e3)/470e3)*1.1 = Vmax = 3.44 Volts
   // 3.44/1023 = Volts per bit = 0.003363075

   int batteryPcnt = sensorValue / 10;

   #ifdef MY_DEBUG
   float batteryV  = sensorValue * 0.003363075;
   Serial.print("Battery Voltage: ");
   Serial.print(batteryV);
   Serial.println(" V");

   Serial.print("Battery percent: ");
   Serial.print(batteryPcnt);
   Serial.println(" %");
   #endif

   if (oldBatteryPcnt != batteryPcnt) {
     // Power up radio after sleep
     sendBatteryLevel(batteryPcnt);
     oldBatteryPcnt = batteryPcnt;
   }
   sleep(SLEEP_TIME);
}```

[tonnerre33]

Ok it's not a problem with the analogReference, you can delete this part of code.
Did you control your resistance value and did you do this schema ?