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💬 Battery Powered Sensors

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  • mfalkviddM mfalkvidd

    @sineverba your wiring looks quite odd. Especially compared to https://learn.adafruit.com/dht-humidity-sensing-on-raspberry-pi-with-gdocs-logging/overview
    Where did you find the wiring guide?

    S Offline
    S Offline
    sineverba
    Hardware Contributor
    wrote on last edited by sineverba
    #139

    @mfalkvidd do u mean the DHT? I can assire you that resistor is between data and VCC ;-) maybe semms strange for need of arrangement on frtzing....... in effect at 3,3 it works and it works in another noce (at 3,3) i would understand because at 5v it doesnt works and serial is flooded ...... I could also post a picture of real breadboard :-)

    Thank you!

    mfalkviddM 1 Reply Last reply
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    • S sineverba

      @mfalkvidd do u mean the DHT? I can assire you that resistor is between data and VCC ;-) maybe semms strange for need of arrangement on frtzing....... in effect at 3,3 it works and it works in another noce (at 3,3) i would understand because at 5v it doesnt works and serial is flooded ...... I could also post a picture of real breadboard :-)

      Thank you!

      mfalkviddM Offline
      mfalkviddM Offline
      mfalkvidd
      Mod
      wrote on last edited by
      #140

      @sineverba yes, you're right. It looks a bit different but the connections are equivalent. Sorry for the confusion.

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      • mfalkviddM mfalkvidd

        @sineverba yes, you're right. It looks a bit different but the connections are equivalent. Sorry for the confusion.

        S Offline
        S Offline
        sineverba
        Hardware Contributor
        wrote on last edited by
        #141

        @mfalkvidd no problem ! I can understand the difficult to understand schemas of other people ;-) do you nave btw somw idea for my issues and queation (if I can remove a caos, for example).... Thank you

        mfalkviddM 1 Reply Last reply
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        • S sineverba

          @mfalkvidd no problem ! I can understand the difficult to understand schemas of other people ;-) do you nave btw somw idea for my issues and queation (if I can remove a caos, for example).... Thank you

          mfalkviddM Offline
          mfalkviddM Offline
          mfalkvidd
          Mod
          wrote on last edited by
          #142

          @sineverba sorry, I don't. I have no experience with the bare atmega.

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          • O Offline
            O Offline
            Oliviakrk
            wrote on last edited by
            #143

            How about using rechargeable batteries instead of alkaline? They would be 1.2V instead of 1.5. vmax would be 2.8V ?

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            • O Oliviakrk

              How about using rechargeable batteries instead of alkaline? They would be 1.2V instead of 1.5. vmax would be 2.8V ?

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              sineverba
              Hardware Contributor
              wrote on last edited by
              #144

              @Oliviakrk
              I use recheargeable. At full charge both are 2.74...
              DHT22 at 2.74 doesn't read. It is rated for 3.3v - 6v

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              • S sineverba

                @Oliviakrk
                I use recheargeable. At full charge both are 2.74...
                DHT22 at 2.74 doesn't read. It is rated for 3.3v - 6v

                O Offline
                O Offline
                Oliviakrk
                wrote on last edited by
                #145

                @sineverba
                Yes, so a stepup before DHT 22 is required. And it works...But..I have issues with measuring battery level.

                int batteryPcnt = sensorValue / 10;
                

                Always gives something around 74-77%. Even if I use batteries straight of the charger (Panasonic/Sanyo Enelops, which are 1,3 -1,4V when taken of the charger)

                gohanG 1 Reply Last reply
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                • S Offline
                  S Offline
                  selvakn
                  wrote on last edited by
                  #146

                  There is minor correction in the battery level measurement calculation. It should be 1.1 * (1 * 10^6 + 470 * 10^3) / (470 * 10^3) = 3.44V

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                  • O Oliviakrk

                    @sineverba
                    Yes, so a stepup before DHT 22 is required. And it works...But..I have issues with measuring battery level.

                    int batteryPcnt = sensorValue / 10;
                    

                    Always gives something around 74-77%. Even if I use batteries straight of the charger (Panasonic/Sanyo Enelops, which are 1,3 -1,4V when taken of the charger)

                    gohanG Offline
                    gohanG Offline
                    gohan
                    Mod
                    wrote on last edited by
                    #147

                    @Oliviakrk Look in comments in the code

                    // 3.44/1023 = Volts per bit = 0.003363075
                    

                    if your batteries put out a total of 2.8V the voltage divider is set to use a Vmax of 3.44V (that suits the alkaline batteries), that is probably why. If you want you could change the voltage divider for a lower Vmax

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                    • sundberg84S sundberg84

                      @FatBeard - I would start by changing the Nrf24l01+ - there are some really bad ones out there.
                      Second I would rewire everyhing from/to the radio. After that I would rewire everything else and maybe change the arduino. As you said, removing all sensors and try debug in "bare minimun" (Power, Arudino and Radio) is a good idea. You can create a fake motion sensor sketch for example sending 1/0 with a 10 sec delay in between just to test the setup (without sensor attached).

                      F Offline
                      F Offline
                      FatBeard
                      wrote on last edited by
                      #148

                      @sundberg84 To give you an update. I've changed from a dht22 sensor to a bme280 i2c sensor. The sensor is running off a4 and 5 and power is gotten directory from 2aa batteries. My original problem is gone in that it's working fine as a mysensors node. My issue though is when in sleep mode, i'm running at 1ma, when i would expect to be down in the low ua area. Any thoughts? The code i'm using is based off of this thread: https://forum.mysensors.org/topic/3816/bme280-temp-humidity-pressure-sensor/5

                      sundberg84S 1 Reply Last reply
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                      • F FatBeard

                        @sundberg84 To give you an update. I've changed from a dht22 sensor to a bme280 i2c sensor. The sensor is running off a4 and 5 and power is gotten directory from 2aa batteries. My original problem is gone in that it's working fine as a mysensors node. My issue though is when in sleep mode, i'm running at 1ma, when i would expect to be down in the low ua area. Any thoughts? The code i'm using is based off of this thread: https://forum.mysensors.org/topic/3816/bme280-temp-humidity-pressure-sensor/5

                        sundberg84S Offline
                        sundberg84S Offline
                        sundberg84
                        Hardware Contributor
                        wrote on last edited by
                        #149

                        @FatBeard I looked at the datasheet and you should expect only a couple of uA... not mA. I would first disconnect the sensor and make sure it's not the other setup that draws power. Did you remove led and volt. reg.?

                        If the sensor still draws power I would either try another one or power it from a digital pin and turn power off before sleep with LOW.

                        F 1 Reply Last reply
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                        • sundberg84S sundberg84

                          @FatBeard I looked at the datasheet and you should expect only a couple of uA... not mA. I would first disconnect the sensor and make sure it's not the other setup that draws power. Did you remove led and volt. reg.?

                          If the sensor still draws power I would either try another one or power it from a digital pin and turn power off before sleep with LOW.

                          F Offline
                          F Offline
                          FatBeard
                          wrote on last edited by
                          #150

                          @sundberg84 Thanks Sunberg, pretty much sorted now. It was the sensor, i changed libraries and it solved my problem. In theory i was using the forced read with both, but only the sparkfun bme280 library worked in reducing the power. To the best of my knowledge, i'm now running at 6ua most of the time with a 60ms (i timed from beginning to end of the loop method) jump to 1amp every three minutes to get a reading. It's difficult for me to capture the amps properly as when i put my uni-t digital multimeter into the circuit, the nrf stops working. Any thoughts on why that might be?

                          sundberg84S 1 Reply Last reply
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                          • gohanG Offline
                            gohanG Offline
                            gohan
                            Mod
                            wrote on last edited by
                            #151

                            1 Amp is definitely a lot. I think it can't be a correct reading

                            1 Reply Last reply
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                            • F FatBeard

                              @sundberg84 Thanks Sunberg, pretty much sorted now. It was the sensor, i changed libraries and it solved my problem. In theory i was using the forced read with both, but only the sparkfun bme280 library worked in reducing the power. To the best of my knowledge, i'm now running at 6ua most of the time with a 60ms (i timed from beginning to end of the loop method) jump to 1amp every three minutes to get a reading. It's difficult for me to capture the amps properly as when i put my uni-t digital multimeter into the circuit, the nrf stops working. Any thoughts on why that might be?

                              sundberg84S Offline
                              sundberg84S Offline
                              sundberg84
                              Hardware Contributor
                              wrote on last edited by
                              #152

                              @FatBeard - as @gohan said - 1A can not be correct. Something is wrong.
                              If the radio does not work, and the sensors if fishy... I would disconnect it and run the radio/atmega only and fake a sensor value to send and see what happens.

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                              • sundberg84S sundberg84

                                @FatBeard - as @gohan said - 1A can not be correct. Something is wrong.
                                If the radio does not work, and the sensors if fishy... I would disconnect it and run the radio/atmega only and fake a sensor value to send and see what happens.

                                F Offline
                                F Offline
                                FatBeard
                                wrote on last edited by
                                #153

                                @sundberg84 @gohan. Apologies , that's a typo on my part. It jumps to 1ma do 60ms from 6ua. Which I'm happy with I think. My question was more how I can measure it properly. The multimeter seems to be effecting the circuit.

                                sundberg84S gohanG 2 Replies Last reply
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                                • F FatBeard

                                  @sundberg84 @gohan. Apologies , that's a typo on my part. It jumps to 1ma do 60ms from 6ua. Which I'm happy with I think. My question was more how I can measure it properly. The multimeter seems to be effecting the circuit.

                                  sundberg84S Offline
                                  sundberg84S Offline
                                  sundberg84
                                  Hardware Contributor
                                  wrote on last edited by
                                  #154
                                  This post is deleted!
                                  1 Reply Last reply
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                                  • F FatBeard

                                    @sundberg84 @gohan. Apologies , that's a typo on my part. It jumps to 1ma do 60ms from 6ua. Which I'm happy with I think. My question was more how I can measure it properly. The multimeter seems to be effecting the circuit.

                                    gohanG Offline
                                    gohanG Offline
                                    gohan
                                    Mod
                                    wrote on last edited by
                                    #155

                                    @FatBeard actually what you really need to measure is the sleep current as it is the state where the node will be spending all of its time. Where are you connecting the multimeter for measuring current?

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                                    • gohanG gohan

                                      @FatBeard actually what you really need to measure is the sleep current as it is the state where the node will be spending all of its time. Where are you connecting the multimeter for measuring current?

                                      F Offline
                                      F Offline
                                      FatBeard
                                      wrote on last edited by
                                      #156

                                      @gohan between positive end of one of the two aa batteries and where it enters circuit. If I start off by having battery connected, the release it slowly with the multimeter attached and without breaking circuit I get my 6ua. However after the timer runs out and the radio comes back on I'm stuck at 1ma. The radio at that point doesn't want to work and it doesn't return to 6ua

                                      YveauxY 1 Reply Last reply
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                                      • F FatBeard

                                        @gohan between positive end of one of the two aa batteries and where it enters circuit. If I start off by having battery connected, the release it slowly with the multimeter attached and without breaking circuit I get my 6ua. However after the timer runs out and the radio comes back on I'm stuck at 1ma. The radio at that point doesn't want to work and it doesn't return to 6ua

                                        YveauxY Offline
                                        YveauxY Offline
                                        Yveaux
                                        Mod
                                        wrote on last edited by
                                        #157

                                        @FatBeard the burden voltage of your multimeter might be too large, which would reduce the voltage to the atmega below its working level.
                                        You're measuring current, so the meter must be in series with the power supply. It's not clear to me how you can remove the multimeter without breaking power to the atmega.

                                        http://yveaux.blogspot.nl

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                                        • gohanG Offline
                                          gohanG Offline
                                          gohan
                                          Mod
                                          wrote on last edited by
                                          #158

                                          You could try to add a booster to power the Arduino or change the multimeter 😀

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