Temperature Spikes

Robert.Wall · 2022-01-31T21:54:45.769Z

Any ideas ?

In short - no.

I am fairly confident that the wrong values you are seeing are not errors coming from the DS18B20 sensor, the data from the sensor is protected by a checksum and if the data itself were being corrupted in transit, the checksum would surely fail.

I think your first suspicion - that it is something external that happens at the same time each day - is the likeliest explanation, but it might not be on your premises, it could be mains-borne.

I hope it’s a silly question - you, or someone within radio range, don’t have another node with the same ID also sending temperature data? There is nothing to prevent that from happening, so although highly unlikely, it is possible.

nikall · 2022-01-31T22:25:00.331Z

Hi Robert,

Nice to talk you again

I only have an emonPi and the DS18B20 is soldered on the board. The whole device (emonPi + Raspberry) are installed outside my home inside the box that the mains cables are being connected to the home. I don’t use any radio node but I don’t know if there is any in the neighborhood but it’s very unlikely to exist. It’s not a very populated area.

I’m straggling to think of any possible cause for this discrepancy. For sure it’s not the sensor otherwise the spike would be random. I also checked if some scripts are running by cron or systemd timer but didn’t find something.

Any other possible or impossible ideas ?

Robert.Wall · 2022-01-31T22:39:55.895Z

nikall:

I only have an emonPi and the DS18B20 is soldered on the board. The whole device (emonPi + Raspberry)

What exactly have you got? The “shop” emonPi has the Raspberry Pi inside the aluminium box, and the temperature sensor is normally external, connected using the RJ45 connector.

nikall:

For sure it’s not the sensor otherwise the spike would be random.

I would have thought so too, but I would not rule it out until it is proven good. Is yours a genuine Dallas/Maxim DS18B20, or could it be a “clone” - see Ds18b20 and emonTX3CM firmware - post 78 in particular.

nikall · 2022-02-01T09:48:37.771Z

Hello Robert

Robert.Wall:

What exactly have you got? The “shop” emonPi has the Raspberry Pi inside the aluminium box, and the temperature sensor is normally external, connected using the RJ45 connector.

I bought just the emonPi board along with the AC adapter. I connected it on a raspi 3B+. It runs perfectly so far except the issues with the temperature sensor. The sensor had a cable around 50cm I suppose with shielding. I didn’t crimple a connector on the cable. It was easier to solder it on the board.

Robert.Wall:

I would have thought so too, but I would not rule it out until it is proven good. Is yours a genuine Dallas/Maxim DS18B20, or could it be a “clone” - see Ds18b20 and emonTX3CM firmware - post 78 in particular.

The sensor was bought many years ago for some arduino project from China but haven’t been used since till now. It’s supposed to be an original but I can’t be sure without removing the shrink tube and inspecting the chip.

nikall · 2022-02-01T09:51:19.087Z

image1136×687 38.7 KB

That’s todays spike. This time with a delay of 11 minutes.

And a comparison with power graph.

image1137×576 38.3 KB

borpin · 2022-02-01T10:07:59.299Z

I’d pretty much guarantee that something is warming the sensor. That isn’t a ‘spike’ it is a gradual warming and cooling.

An animal sitting on the sensor, something heating the box (the sun?).

Put in a time lapse camera and see what you find.

nikall · 2022-02-01T10:33:26.830Z

Hello Brian,

thanks for the reply

Well, you may be right. The box is located mostly in the shade except of the morning hours. Meanwhile, I have moved the sensor location from it’s original place when I was trying to arrange the boards inside the main connection box. I will put some insulation foam or something outside the box in the spot where the sensor is installed and check again the temperature readings.

I’ll get back here to report the findings.

BTW, do you or Robert have a clue on how to read the UID of the sensor ? Do you report it somewhere in a log file during the initialization of the microcontroller ? I have compiled a small sketch to read the ID but I have to load it in the MC to run it and I don’t want to mesh with something and get into troubles.

Robert.Wall · 2022-02-01T12:10:24.583Z

nikall:

how to read the UID of the sensor ? Do you report it somewhere in a log file during the initialization of the microcontroller ?

No, the serial number is read and stored by the sketch that runs in the Atmel ATMega 328P on the emonPi Shield, but it never normally leaves that, it’s not written anywhere. If you have the emonPiCM software, then this can report the serial number, the ‘standard’ software cannot.

nikall:

Well, you may be right.

I think Brian is right - that is a genuine temperature change, it is rising by about 0.3°C per minute. There is no doubt in my mind that the sensor is reading correctly.

nikall:

I will put some insulation foam or something outside the box

I would try something that will reflect the heat away, like aluminium foil, on top of the insulation.

nikall · 2022-02-01T15:50:57.803Z

Robert.Wall:

I would try something that will reflect the heat away, like aluminium foil, on top of the insulation.

Yeah, I think Brian is right. I just didn’t realize how much difference they make some minutes of direct sun during winter. I thought that impact would be more or less a couple of degrees.

Yes I will insulate using some blanket like those being used in ovens and other similar appliances or I will DIY something.

Thank you all for your help!

nikall · 2022-02-01T15:59:40.262Z

Robert.Wall:

If you have the emonPiCM software, then this can report the serial number, the ‘standard’ software cannot.

I saw a post of yours describing some different versions of FW for the MC but to be honest I didn’t understand too much of what are the differences and why should I use it. If you can elaborate a bit on my specific case applied to the emonPi only, then I might give it a try.

Robert.Wall · 2022-02-01T16:59:46.414Z

nikall:

I didn’t understand too much of what are the differences and why should I use it.

All it is, is it makes the emonPi measure in exactly the same way that the latest emonTx measures - continuously like your electricity meter does, rather than taking a short sample every 5 or 10 seconds and assuming that’s representative.

nikall · 2022-02-01T18:18:43.226Z

OK I got it!

It’s the firmware you were referred to when you told me that I could calibrate the CT values from within the serial monitor.

Since I have already done this in the current firmware I will just add the correct calibration factor value to the sketch and just compile and upload. Then I can check and change the values (if needed) through the serial monitor.

EDIT

Compilation with pio run succeeded but I can’t upload it. I used --upload-port /dev/ttyAMA0 but avrdude spits out some sync errors. This never happened with the “standard” firmware.

Any help would be great (and appreciated)

EDIT 2
I compared platformio.ini of the standard and CM firmware and there are quite a few differences. I suppose that I have to adjust some variables in order to compile and upload without issues…?

Robert.Wall · 2022-02-01T19:29:29.944Z

I cannot recommend platformio - it destroyed my system when I tried it, and it took hours to put everything back in the right places. I only ever use the Arduino IDE, so I’m afraid I cannot help you.

borpin · 2022-02-01T21:49:42.097Z

nikall:

but avrdude spits out some sync errors.

seen that, but it worked fine eventually.

Are you uploading from the Pi? I did some docs a while ago about how to do that GitHub - openenergymonitor/EmonTxV3CM: EmonTxV3 Continuous Monitoring Firmware (Default shipped EmonTxV3 firmware) and this post emonTx not sending CT data - #21 by borpin

PIO is fine, and anyway, by this point, you are not using it.

Did you stop emonhub first?

nikall · 2022-02-02T09:47:43.711Z

Robert.Wall:

I cannot recommend platformio - it destroyed my system when I tried it, and it took hours to put everything back in the right places. I only ever use the Arduino IDE, so I’m afraid I cannot help you.

It’s OK Robert. Your help so far is priceless to me. I too don’t use pio but I wanted to compile the firmware on the raspberry so to make things simpler. The obvious solution was pio.

nikall · 2022-02-02T10:00:42.657Z

borpin:

Are you uploading from the Pi?

Hi Brian,
Yes, I compile and upload from the Pi where the emonPi is connected to.

borpin:

Did you stop emonhub first?

Yes I did but the result was the same. See what I did in short:

I cloned this repo locally on the Pi and compiled it (after installing the necessary dependencies) with pio run.

After I saw that the test run was OK I did a sudo pio run -t upload

The output is the following.

Warning! Please install `99-platformio-udev.rules`.
More details: https://docs.platformio.org/page/faq.html#platformio-udev-rules

Error: Please specify `upload_port` for environment or use global `--upload-port` option.
For some development platforms it can be a USB flash drive (i.e. /media/<user>/<device name>)
*** [upload] Explicit exit, status 1

I Ignored the warning for the udev rules because I don’t think is the case since I have uploaded before the “original” firmware without issues and I just added the --upload-port=/dev/ttyAMA0 to the command input. After issuing again the command (and having stopped emonhub service) I got the following output:

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xfc
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0xe0
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x8e
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x1c
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x8e
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0xe0
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x8e
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0xfc
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x70
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0xe0

And the upload failed.

Please let me know if something in the procedure above is wrong.

Thank you!

borpin · 2022-02-02T10:17:02.271Z

nikall:

After I saw that the test run was OK I did a sudo pio run -t upload

Did you read the instruction link I sent?

That command doesn’t work for a number of reasons.

borpin:

I did some docs a while ago about how to do that GitHub - openenergymonitor/EmonTxV3CM: EmonTxV3 Continuous Monitoring Firmware (Default shipped EmonTxV3 firmware) and this post emonTx not sending CT data - #21 by borpin

nikall · 2022-02-02T10:22:27.238Z

Should I use this instead?

avrdude -v -c arduino -p ATMEGA328P -P /dev/ttyAMA0 -b 115200 -U flash:w:output.hex

borpin · 2022-02-02T10:23:46.339Z

You should follow the whole set of instructions as it creates the HEX file to upload. You can’t just pick and choose bits of a set of instructions.

Note the line “If the emonTX is connected to the RPi via the serial interface” (which perhaps could be clearer).

Also, you may need to edit the file /opt/openenergymonitor/avrdude-rpi/autoreset and change the pin number to 12.

EmonTX to Rpi - Direct Serial Connection Getting Started

Took my life in my hands and Success!! . Having installed the system using the emonScripts, some of the elements were already in place. First compile the sketch. I know that @Robert.Wall is not keen on PlatformIO, but on the Pi it installed and worked flawlessly as described here GitHub - openenergymonitor/EmonTxV3CM: EmonTxV3 Continuous Monitoring Firmware (Default shipped EmonTxV3 firmware). The only oddity is creating the hex file. That instruction says use the upload option but t…

nikall · 2022-02-02T11:14:17.664Z

Brian,

I managed to upload the firmware I didn’t anyway strictly follow the document but it was a success.

The problem is that all the feeds and graphs stopped working. I confirmed that firmware is indeed OK by using the serial monitor. There I saw that FW version is 1.0 and I saw readings coming in but feeds were all dead.

Do I have to reconfigure everything ? And if yes, what about the previous records ?

EDIT
I think I found what I missed out. It’s the emonhub.conf…Right?