💬 Battery Powered Sensors

ricorico94

Hi,
I'm trying to build a Soil Moisture sensor with NiMh battery and solar panel as in another post. I use a stepup converter to 3.3V connected on the VCC of a pro-mini 3.3V. The sensor seems working when connected to FTDI USB device, ut once I remove the power from FTDI, no more communication. I measured the voltage on the output of the stepup which indicates 3.26V. Is it norml or a defective step-up ? And should I remove the regulator of the pro-mini as suggested above or not ? (in article above, it states the regulator is not necessary, but it doesn't say if pro-mini would still work if regulator remains there).
Thanks for your support

mfalkvidd

@ricorico94 what does the debug output from the node and the gateway say?

What regulator are you using? Most regulators produce power that is too noisy to be usable by the nrf24 radio (you didn't state which radio you're using so I'm just guessing here, based on the most common problems). What capacitor(s) are you using after the regulator?

See https://forum.mysensors.org/topic/666/debug-faq-and-how-ask-for-help/ for the most common problems and how to diagnose them.

Also see https://www.mysensors.org/build/battery for more information about battery powered sensors.

ricorico94

Hi,
As regulator I use a stepup like that one:
https://fr.aliexpress.com/item/DC-DC-0-8-3-3V-to-3-3V-Step-Up-Boost-Power-Module-For-Arduino/32819660926.html?spm=a2g0s.9042311.0.0.27426c37HEbdcz

I use a NRF24L01 as radio module following the connection guidelines from Mysensors. I did not add any capacitor to 3.3 and ground of the NRF24L01.
I connected the vO of the stepup to the VCC (the VCC between RX and GRD and not the RAW) of the arduino pro mini 3.3V as indicated in this post:https://forum.mysensors.org/topic/4045/solar-powered-soil-moisture-sensor
I use indeed a similar lamp with its small NiMh battery (1.2v) and its solar panel.
The NRF24L01 is connected on GRD (between RST and RAW) and on VCC (between A3 and RST). I hadn't put any capacitor.
I tried following your advice to add a 0.1uF ceramic capcitor between VCC (the one between RX and GRD) of pro mini and its ground, but apparently, I face same issue.
(I did not solder the capcitor yet, I only connected through the pins I usually use for the FTDI)

16 MCO:BGN:INIT NODE,CP=RNNNA---,VER=2.2.0
26 TSM:INIT
28 TSF:WUR:MS=0
34 TSM:INIT:TSP OK
36 TSF:SID:OK,ID=4
38 TSM:FPAR
75 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
2084 !TSM:FPAR:NO REPLY
2086 TSM:FPAR
2123 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
4130 !TSM:FPAR:NO REPLY
4132 TSM:FPAR
4169 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
6176 !TSM:FPAR:NO REPLY
6178 TSM:FPAR
6215 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
8222 !TSM:FPAR:FAIL
8224 TSM:FAIL:CNT=1
8226 TSM:FAIL:DIS
8228 TSF:TDI:TSL
18229 TSM:FAIL:RE-INIT
18231 TSM:INIT
18237 TSM:INIT:TSP OK
18241 TSF:SID:OK,ID=4
18243 TSM:FPAR
18280 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
20289 !TSM:FPAR:NO REPLY
20291 TSM:FPAR
20328 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
22337 !TSM:FPAR:NO REPLY
22339 TSM:FPAR
22376 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
24385 !TSM:FPAR:NO REPLY
24387 TSM:FPAR
24424 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
26433 !TSM:FPAR:FAIL
26435 TSM:FAIL:CNT=2
26437 TSM:FAIL:DIS
26439 TSF:TDI:TSL
36442 TSM:FAIL:RE-INIT
36444 TSM:INIT
36450 TSM:INIT:TSP OK
36454 TSF:SID:OK,ID=4
36456 TSM:FPAR
36493 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
38502 !TSM:FPAR:NO REPLY
38504 TSM:FPAR
38541 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
40550 !TSM:FPAR:NO REPLY
40552 TSM:FPAR
40589 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
42598 !TSM:FPAR:NO REPLY
42600 TSM:FPAR
42637 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
44646 !TSM:FPAR:FAIL
44648 TSM:FAIL:CNT=3
44650 TSM:FAIL:DIS
44652 TSF:TDI:TSL
54657 TSM:FAIL:RE-INIT
54659 TSM:INIT
54665 TSM:INIT:TSP OK
54669 TSF:SID:OK,ID=4
54671 TSM:FPAR
54708 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
56717 !TSM:FPAR:NO REPLY
56719 TSM:FPAR
56756 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
57493 TSF:MSG:READ,0-0-4,s=255,c=3,t=8,pt=1,l=1,sg=0:0
57499 TSF:MSG:FPAR OK,ID=0,D=1
58765 TSM:FPAR:OK
58767 TSM:ID
58767 TSM:ID:OK
58769 TSM:UPL
58806 !TSF:MSG:SEND,4-4-0-0,s=255,c=3,t=24,pt=1,l=1,sg=0,ft=0,st=NACK:1
60815 TSM:UPL
60852 !TSF:MSG:SEND,4-4-0-0,s=255,c=3,t=24,pt=1,l=1,sg=0,ft=1,st=NACK:1
62861 TSM:UPL
62863 TSF:MSG:SEND,4-4-0-0,s=255,c=3,t=24,pt=1,l=1,sg=0,ft=2,st=OK:1
64872 TSM:UPL
64909 !TSF:MSG:SEND,4-4-0-0,s=255,c=3,t=24,pt=1,l=1,sg=0,ft=0,st=NACK:1
66918 !TSM:UPL:FAIL
66920 TSM:FPAR
66957 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=1,st=OK:
68964 !TSM:FPAR:NO REPLY
68966 TSM:FPAR
69003 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
71012 !TSM:FPAR:NO REPLY
71014 TSM:FPAR
71051 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
73060 !TSM:FPAR:NO REPLY
73062 TSM:FPAR
73099 TSF:MSG:SEND,4-4-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
75108 !TSM:FPAR:FAIL
75110 TSM:FAIL:CNT=4
75112 TSM:FAIL:DIS
75114 TSF:TDI:TSL

Apparently, it sends correctly packets but can't receive any ACK or message from the gateway.
I got this log by connecting a FTDI adapter with only the RX/TX cables. If ever I connect also the GRD and 3.3V of the FTDI, then I get no error message at all (even without the capacitor) and Domoticz receives all updates (and also sends as I use Domoticz to send customized sleep duration to the sensor).

Should I try adding both the 0.1uF to VCC/GRD of arduino and also a 4.7uF to the 3.3/GRD of the NRF24 as suggested in the "Connect the Radio" page ?
Any idea ?
br,
Rico

mfalkvidd

@ricorico94 yes add the recommended capacitor.
Also check the gateway log at the same time you check the node log. That will let you know if the gateway isn't hearing the node, or if the node isn't hearing the gateway.

ricorico94

Thanks for the advice, I'll try that.
For the log on the gateway side : I use a gateway on the raspberry pi itself (as per https://www.mysensors.org/build/raspberry ) of my Domoticz installation. Is there an easy way (like via telnet) to get the logs other than by creating the new line in the config file ? Maybe the 3rd option proposed with "mysgw.pipe" ? (in such case, do I need to reboot whole raspberry after modifying the config file?)

mfalkvidd

@ricorico94 follow the instructions at https://www.mysensors.org/build/raspberry#troubleshooting

ricorico94

Thanks to another arduino forum, I found what was wrong.. probably indeed a stability of power due to step-up converter. In that forum, they were explaining that receiving is more sensitive to power noise than sending data and that in such case, it's good to add a 100uF capacitor on 3.3V and GRD of radio module. I tried 100uF and it worked.. I then tried with 47uF and it's still working. (I had tried with 0.47uF and it was not working at all)

In the "Connect Radio" guidelines, of Mysensors, it is stated that a capacitor of 0,47-47uF is improving reliability but that "the exact size usually doesn't matter" which was misleading in my case.
Could I suggest to rephrase that sentence into "the exact size usually doesn't matter, but you can try 47uF if 0.47uF still doesn't work, especially if sending data works well and not receiving data." ?

Edit for Erratum: please read 4.7-47uF instead of 0,47uF-47uF. Tests I had made were with 4.7uF as well, not 0.47uF
br,
Ricorico94

mfalkvidd

@ricorico94 great input, thanks! I have updated the page, except that I changed 0.47uF to 4.7uF in your text since the recommendation is 4.7 - 47)

ricorico94

oups, indeed. I'll edit my post as well to avoid confusion as well. Thank you for your support, I appreciated a lot.
By the way, I could never find how to get the logs in my gateway installed on raspPI. But that's another post. ;-)

Maschler

Hello together,

I'm just trying to get the voltage measurement to work. But there is something wrong. I built everything as shown above and uploaded the program to the Arduino pro mini. The only thing I changed is the sensing Pin A0 -> A3
In debug mode I see the following (the supply voltage is constant 3.3V):

Battery Voltage: 3.12 V
Battery percent: 92 %

Battery Voltage: 2.40 V
Battery percent: 71 %

Battery Voltage: 2.32 V
Battery percent: 69 %

Battery Voltage: 2.31 V
Battery percent: 68 %

Battery Voltage: 2.29 V
Battery percent: 68 %

Battery Voltage: 2.30 V
Battery percent: 68 %

Battery Voltage: 2.33 V
Battery percent: 69 %

What could be the reason? That doesn't make sense to me.

zboblamont

@maschler You may be picking up noise which will give an unsteady voltage during the ADC sample.
A 0.1uF electrolytic cap between the analogue pin and ground in parallel with the resistor should stabilise it sufficiently.
I use this arrangement with much higher resistances which are known to increase noise, the capacitor maintains a steady voltage sufficient for the ADC sample period.
One thing worth checking with a multimeter is what the actual voltage is on supply and on the pin. The 1.1v bandgap is sometimes not exactly 1.1v, particularly on clones. Once you know the two values you can modify the ratio and you should get reliable and accurate readings.

gohan

The 1.1v reference could be + or - 10%, but a small ceramic cap on near the analog pin should help to stabilize the reading. Also taking 3 measures and then sending the average is a good way of minimizing errors

alowhum

I'm looking for a USB rechargeable battery that can deal with very low power drain, so that I can power an Arduino Nano. Most power packs will not work with very small currents - they turn themselves off. So ideally it should not be too clever..

Does anybody have a favourite?

gohan

https://www.aliexpress.com/item/ESP32-ESP32S-For-Wemos-For-Raspberry-Pi-18650-Battery-Charge-Shield-Board-V3-Micro-USB-Port/32843629344.html

nekitoss

It would be great to add to this arctle that if you want to be battery powered outdoors with temperature below zero - you have to use lithium batteries (FR6 for AA) (yes, batteries, not li-ion accumulators!) (for example ultimate lithium energizer, also could be found lithium batteries from other vendors), because Alkaline (LR6 for AA) will be frozen and loose their capacity heavily. If i remember it is >50% at -10 C and death at -20 C. Same problem for li-ion accumulators - when liquid is frozen - electrons are stucked...
Also would be great to add some link about battery/accumulator types, advanteges and disadvantages, but i have no links in english, easy-to-read and in one place...

But i have very great link about battery-powering that really should be added here, but in advanced section:
http://www.gammon.com.au/power

zboblamont

@nekitoss Not sure where you got your information but my Gas Node is on it's second year running on the same two Varta AA alkalines and been down to -20 on more than a few occasions last winter, typically 4 months below -10... Currently the temperature is -3 and headed to -8 overnight, voltage is 2.98, will probably need to replace them in autumn 2019...

benhub

The tap point could be bypassed with a 0.1 uF capacitor

Can someone explain, how exactly I should connect this capacitor? Should it be between A0 and GND? Would be great to see this capacitor in the graphic.

zboblamont

@benhub That rather depends what you are quoting from, as could not find the original statement.
If it is to do with stabilising voltage from a point on a resistor divider to read it on the analogue pin, the capacitor is from the analogue pin to ground.
It's purpose to dampen oscillations long enough for the ADC to sample the voltage, but usually only where high value resistances are used.

tonbor

The quote is from this sample : Measuring and Reporting Battery Level

Use a 1MΩ (R1) and 470KΩ (R2) resistor in series, connected to the positive terminal on the battery and ground and then connected the tap point to the A0 input on the CPU.

The tap point could be bypassed with a 0.1 uF capacitor to keep the noise level low, at this otherwise high impedance point.

skywatch

@tonbor Yes, the capacitor goes from the analog input to ground.

💬 Battery Powered Sensors

2

11.7k

11.2k

113.0k