You are right !

For fans of the streetfighter franchise it's quite easy to memorize: RI=U

@@VincentFischer Or for the Swiss: U = RI

@@markusmohr5470 I was taught I = V/R Same but different symbols

I learned V = I * R. Pretty basic.

Thank you!

Yeahh

Thank you for your nice words!

Many thanks!

Thank you for the nice words. We are glad to help!

I asked Google what you weree searching yesterday and adapted the viceo accordingly ;-)

Sorry that I was too late!

Glad to read that you can use the content!

@@AndreasSpiess Is it possible to cover power measuring sensors with data logging function in future?

I do not think so because we build our loggers ourselves ;-) So the topic is probably too special for most of my viewers.

Fantastic! I have not problems wit hCovid-19 because I live in the basement while creating videos ;-)

Thank you for sharing your experience!

Thank you for sharing your experience!

Glad you can use it!

Have fun!

Thank you for your kind words! You chose a nice place to judge about our country ;-)

The subtitles are made by Luciana, my Translator.

Happy to help! You are also one of my most loyal subscribers!

An interesting part. An "INA219" with a hall sensor! Good choice.

You are welcome!

Good luck with your project!

You are right. When I made the video I did not yet recognize that the INA219 can measure current in both directions :-(

Thank you!

Just bear in mind that, just as with clamp-style multimeters and current transformers in general, you have to pass *only one* of the current-carrying wires through the loop of the sensor. So for an AC mains appliance you can pass through the sensor EITHER the line wire (aka live/phase/hot) OR the neutral wire (aka return), and most of the time that still requires modifying the cable (at least to remove the outer layer of insulation for countries/appliances that use double-insulated mains cables) or creating some kind of adapter that you can plug the appliance in to. If you were to pass a mains-powered appliance's cable as a whole through such a sensor it would read zero - or at least close to zero - as the field generated by the current flowing one way in the line wire would be cancelled out by the opposite current in the neutral wire. (There may be a small non-zero reading as a result of sensor error, any current leaking to earth external to the cable [hopefully none!], and - I'm not at all sure about this - maybe even non-unity power factor from capacitive/inductive loads, such as motors, switch-mode power supplies, etc.) And actually, all of these sensors have limited value for measuring mains AC appliances for two reasons: all they tell you is the current - and is that RMS current or the instantaneous current at the time your MCU decided to make a reading? After all, the current draw of most AC appliances goes up and down alongside the sine wave of the voltage! Without knowing the supply voltage, you can't know the power consumed, which is often what we're more interested in. Yes you can estimate the supply voltage at 100/110/115/120/220/230/240V RMS nominal (any I missed there?! 😹), but in practice that varies throughout the day, and thanks to the nightmare that is power factor, unless you know the true, not-RMS voltage (i.e. the exact point on the voltage sine wave - between ±141V [100V RMS] and ±340V [240V RMS]) at the moment the current was measured, at best you're probably only calculating apparent power, not real power; see en.wikipedia.org/wiki/Volt-ampere I've used some smart-home-style current-transformer clamp-based devices that are designed to be clipped around one of the wires leading to/from the house's electricity meter, and I found that they differed from the correct value (as measured by the electricity meter itself) by 20-30%, which I figure is mostly because they have no reference to the mains voltage, so they have to rely on an estimate of the RMS voltage and *a complete guess* at the house's overall power factor! :S

@@AndrewGillard very clear thank you for these details

Glad it was helpful!

Perfect! I hope everything is ok on your side? Covid-19 maybe has a long way to get to Lincoln, so you might be lucky ;-)

@@AndreasSpiess The neighbor across my house returned week ago from hospital, almost died, he had Covid-19! I spoke to his wife, about 5 meters away, and she did not get it or did not have any symptoms at all - like many people, who had it not knowing at all. And I hope you are staying safe also, I don't like you get it at all! Have a great Sunday!

Danke! Nun sollten wir nur noch ins Do-it-Yourself gehen dürfen...

@@AndreasSpiess Na zum Glück stellt die Post noch von AliExpress zu ;-P.

Thanks for sharing your experience!

Jason Pluis adding a battery helps, but luckily you're on the right channel to find out about this sort of thing!:)

Without a battery it is probably easier to use the analog input and decide on the voltage at startup.

Another viewer suggested this part, too. Very nice, but not cheap ;-)

@@AndreasSpiess true, it's not cheap, but come on as a Swiss you are used to that. 😜 But jokes aside, it is very precise and has a very low resistor value. So the voltage drop is minimal and the measurement range is huge.

I’ve used this part in a commercial 1kwh 24v battery pack. It performs very well.

Good luck with your project! Seems to be nice.

6mA on 25A is impressif!

You're welcome!

Thank you for your nice words!

Omar Mekkawy I just checked the data sheet and it does have a sign bit. Also I'm pretty sure I hooked my leads up backward when my mAh tester project the first time and I did get negative current readings when the supply read lower than the load.

You are right. My mistake!

Andreas Spiess, I should have read more of the comments. You stay safe!

@@AndreasSpiess never mind. you are welcome.

Thank you for sharing your experience. I assume they are similar to the ACS712?

Maybe a topic for a quickie...

Glad you enjoyed it!

Maybe you watch my today's video ;-)

My pleasure!

I did not cover mains in particular. There you get other sensors. But I have no overview.

Shit happens... Fortunately they do not cost a fortune...

Glad you liked it!

Just change the resistor and do the calculations according ohms law (the right one, not mine ;-)

:-)

You might be right. But I do not like to cut ground wires...

@@AndreasSpiess One context for using a low-side shunt is when you have panel mounted shunts a distance away from the monitor. It's safer to then have the shunt sensing leads routed to the monitor because they're nearer ground potential. Not sure if it's a matter of personal taste :)

The hand seems to have a lot of fans...

You are right.

Thank you!

I assume the INA219 has a built-in voltage reference. The ACS chips not.

This seems to be a quite complex procedure. But you are right. It seems to work.

They for sure are ok...

You are right, it is a good chip. Welcome on the channel, BTW.

I also do not like to cut ground wires...

The probkem has been, typically, that you need to measure voltages that are higher than the V+ in the DUT, in case where you are measuring your 'own' current consumption, which is a probkem for most amplifiers... of course, low-side measurements make the V- a bit 'floating', but the voltages being measured are referenced to 'ground', making noise suppression easier... high-side measurements also affect the apparent V+ of the DUT. Lots of considerations to make, almost all of them introduce some compromise in the DUT performance/stability, or bandwidth, or sensitivity, or dynamic range, or... I spent a few years doing this stuff...

Which opamps please.

which part number are you using ?

@@OmarMekkawy OPA192

That is not easy. Most concepts use fast switching shunts for that purpose. I covered this issue for smaller currents in the video I suggested.

Glad you enjoyed it!

Glad you enjoyed it!

Maybe I will come back to you with the "RMS tricks" when I prepare a AC current video...

Glad you enjoyed it!

Appreciate it!

I looked at their products. It seems to be a very special product for precision usage. The principle is interesting, but nothing for this channel.

You're welcome

Welcome aboard the channel!

You are right. If you connect the ground of the op-amp to the battery the inputs would be positive.

Andreas Spiess No, you can connect the ground (negative power supply) of the op amp to the Arduino ground. You connect the (+) input of the op amp and the op amp negative power supply to the Arduino ground. You connect the op amp positive power supply to the high side power. You connect, say, a 10K ohm resistor between the power source low side and the op amp (-) input. You connect the same value (or larger, to scale up the output) resistor from the (-) input to the op amp output. This will invert the negative voltage across the 10 ohm resistor to a positive voltage at the op amp output. The op amp drives its output to make the voltages at its (-) and (+) inputs equal: both end up at zero volts (Arduino ground). Thus all the op amp input and output voltages are zero or positive - quite legal! Notes: I have built this circuit and used it in past projects to sense negative voltages with only a positive power supply for the op amp. It works. Carefully read prospective op amp data sheets to select one where the common mode input range includes zero or slightly negative input voltages. This will be true for most op amps that have “Rail-to-Rail” inputs. You also want an op amp with an output range that includes zero volts. This will be true for op amps with “Rail-to-Rail” outputs. Select an op amp that has clamp diodes on its inputs, thus guaranteeing the (-) input cannot go very far negative. The 10K ohm input resistor will limit any transient input currents to the op amp (-) input and its clamp diodes before the op amp output settles.

@@w6wdh, Andreas Spiess and Juergen Schimmer : The Rail-to-Rail feature is not even mandatory as (+) input can be biased to say 1V and the program will cancel that out with a simple I=aX+b (b being negative here). Or did I miss something ?

I assume this is the reason for the INA226 which has such a pin. For safety, this is for sure a good thing. One other sensor also has a comparator on board for that reason.

@@AndreasSpiess yes it's always better to remove software from detecting faults and acting on them, better at times to act then let the software know. i know you can use interrupts, but interrupts make it harder to demonstrate that the code will always work as you cant easy test your code being interrupted in every possible place. Thank for another thought provoking video.

Glad it was helpful!

This is the fate of the guy who stands up and does something...

@@AndreasSpiess wer viel macht , macht viele Fehler, wer wenig macht, mache wenig Fehler, wer nichts macht, macht keine Fehler und wer keine Fehler macht wird befördert.

Da hast du recht. Wahrscheinlich sitze ich deswegen immer noch im Keller ;-) Aber ich bin zufrieden.

Pay attention. Maybe she wants to know what her husband is watching every sunday morning and reads the comment ;-) We all wait till the do-it-yourself shops are open again!

You are welcome!

I assume all the "type 1" sensors would give you results. The hall sensors probably are not sensitive enough.

Look at the RCV420 IC from Burr Brown/Ti, a much better solution, that converts 4-20mA to 0-5v. With an external 16bit ADC i2c such as ADS111x this is a robust solution. www.ti.com/lit/pdf/sbvs019

Glad it was helpful!

You are welcome!

Bitte, gern geschehen!

Very good application. Thanks for the feedback!

Thank you!

Maybe I will make a video about AC current measurement in the future.

Here the worst seems to be manageable. The new infections are constant. The hospitals still have lots of capacity...

Interesting concept. Thank you for sharing!

I did not cover AC in this video. Maybe I will do one in the future...

You are right with the bi-directional. I did not know it and di not read the ".." manual. But I do not like to cut ground wires. That is probably why I did not even look at this possibility.

@@AndreasSpiess I used to monitor charge and discharge so I remembered positive and negative currents. I prefer the High side measurement too. Thanks for the reply ;)

The INA219 does not measure current. It measures voltage across a shunt resistor. For small currents you can increase the resistor value. But then it has other disadvantages. Maybe you watch my videos about deep sleep (e.g. ukposts.info/have/v-deo/hIVzbIiOsbB9uJc.html ) Anyway, I do not think that uA in a typical solar project are important because you probably need at least mA to charge the battery. So you probably need more sun or a bigger panel.

@@AndreasSpiess 1000 times thanks for the help!

So far I have no experience with AC current measrurement. So I cannot help :-(

These sensors are quite fast. They can transfer frequencies of a few kHz. Mabe you consult the datasheet?

@@AndreasSpiess I've just checked again the ACS723 (one I have) and its response time lies between 5µs and 20µs (pages 6 and 21 in the datasheet @ www.digikey.com/en/datasheets/allegro-microsystems-llcacs723datasheetashx ). The response time depends on a bandwidth limiting voltage though. That might be a little too slow, IMHO. The protection I had in mind was a fuse-like surge protection, not some form of current limiting.

My pleasure!

Good to hear!

Drill bits and fingers are not a good team, you are right!

As long as your wife does not intervene ;-)

Glad you like them!

Maybe I will make a video about measuring AC. So far I do not have everything together. The HCPL7510/20 is for sure a candidate.

:-) You are welcome!

Thanks for the info!

The INA260 seems to be very good, but also expensive :-(

@@AndreasSpiess It's fine, especially considering the built-in laser trimmed resistor: A beefy (but lousy +/- 1%) 2mΩ alone does cost around 20% of the whole INA260 with it's 0.1% tolerance resistor. Not to mention that you can use it like that without additional external parts and thus a lot less design issues. Adafruit has a module with it for MSRP $9.95 which sounds very fair and maker friendly to me.

My newer videos get Spanish subtitles (made by an Argentinean Lady). I do not speak Spanish :-(

You are right!

Also the power specs are 20v 13A

Maybe you need an oscilloscope to look at the voltages to understand what happens

4 wire sensors can always be done if you add an independent voltage sensor.

I mainly concentrated on DC. Maybe I will do once a video on AC. Unfortunately this is not my strength :-(

Plus you cannot open this ring. So you had to detach then reattach wire somewhere. That’s precisely what we want to avoid on main!

You are right. But at least you do not have to cut it. Cutting is a no go here. Removing and re-attaching is not easy to prove

Glad you liked it!