Double Micro (nano) Ampere meter

[gohan]

That looks impressive. I'll be waiting for the instructions too 😀

[Nca78]

Wow, that looks nice, I'm stucked with my multimeter and couldn't find the parts avaiable for delivery here to build a µcurrent gold.
Please publish the build instructions !
(Maybe if you could give use the BOM first, then you'll have plenty of time to publish build instruction before we get delivered ;))

[AWI]

@DavidZH Impressive only by numbers ;-) I am prepared to trade my µCurrent for the Agilent :blush:
A meetup sounds good..any specific plans yet?

[AWI]

There it is Micro (nano) ampere meter (double). I need to add a schematic drawing. Any suggestions/ questions are welcome.

[gohan]

Why all those headers are needed?

[korttoma]

Parts ordered :D

[AWI]

@gohan As mentioned in the description: I use it as a "patch panel" to distribute the power and ground to different devices. Wiring tends to get messy on my workbench...

Not mine but similar ;-)

[gohan]

Oh ok, you use it like an integrated breadboard 😀

[sundberg84]

@AWI - did you steal my image on my workbench ;) j/k.
We need to revive the old workbench topic again!

[gohan]

Are resistor needed with a tight tolerance or else?

[AWI]

@gohan No special tolerance resistors needed. The only reason for choosing metal film resistors is that their temperature coefficient is better than carbon types (typical 50ppm/°C compared to 200-500ppm/°C).
As you will be calibrating the circuit you can choose from a large range (0.1 Ohm - 100 Ohm) for the shunt. This will only influence the burden voltage / sensitivity and range (Ohm's laws).

[DavidZH]

@AWI Lemme think about that..... Uuuuuhm. no... 😈

I have no plans for a meetup. Lacking a proper venue for such a thing. Unfortunately.

[NeverDie]

If there is some interest I will try to publish a decent built instruction on Openhardware.io.

I'm interested.

[Nca78]

@NeverDie said in Double Micro (nano) Ampere meter:

I'm interested.

In case you haven't seen it, it's here :
https://forum.mysensors.org/topic/6723/micro-nano-ampere-meter-double/5

[NeverDie]

@Nca78 said in Double Micro (nano) Ampere meter:

@NeverDie said in Double Micro (nano) Ampere meter:

I'm interested.

In case you haven't seen it, it's here :
https://forum.mysensors.org/topic/6723/micro-nano-ampere-meter-double/5

Thanks! It looks a bit complicated to me. I've used one of these breakout boards (https://www.amazon.com/gp/product/B00OPVBEQO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1) as a way to measure 24-bit voltage on capacitors, and it works really well. As you can perhaps tell from the photo:

the chip is fairly simple to use. What I especially liked is that there was already a demo arduino sketch for interfacing with it. That was a real time saver. If I were to build something, I might try that first, if only because it seems like it might be easier (though perhaps, in part, because I'm already comfortable with it). Would using it in conjunction with a sense resistor be all it would take to make an accurate, high resolution current sensor?

[AWI]

@NeverDie that one would work as well. Maybe harder to get and a little more pricy :moneybag:

[AWI]

@NeverDie said in Double Micro (nano) Ampere meter:

It looks a bit complicated to me

btw. Which part looks complicated? It's just a few resistors attached to an ADC board (and sketch ready) I am curious on how you can build something simpler with the ADS1220 (which seems to be a better ADC if you are able to find it somewhere ;-))

[NeverDie]

It sounds like I was mistaken then. In my quick read I thought that I had to implement the entire schematic, not just add a couple of resistors to a pre-made breakout board. I suppose if the schematic were more of a block diagram, that might be clearer for other future readers to quickly grasp, or maybe it's just me.

Why would the ADS1220 be a better ADC? I really haven't looked into doing a comparison. I bought the breakout board that I pictured above from Amazon , but I see that it's out of stock now. I believe the company which made it is in India. I seem to recall that it's open source, so there's always that I suppose. I didn't mind ringing the till for the maker: it was all pre-made, it did what I needed at the time (which was watching in real-time the voltage leakage from supercapacitors that I was testing), it was available with free Amazon Prime delivery, and I wanted something sooner rather than later. So, it fit what I needed at the time. Most of those reasons relate to rapid availability though rather than technical reasons.

[NeverDie]

OK, I received an HX711 and have partially hooked it up. I have it connected to an UNO and powered by the 3.3v pin. I also have AWI's sketch running on the UNO. I haven't yet connected a OLED screen to it, so at the moment I'm just looking at the output of the serial consol, which gives a running output of "average" and "spread". I have 10mv connected between A+ and A- to just to see what it will do.

Looking at the code, it looks as though the button (A2) is normally pulled high. Is the button supposed to be connected to GND through a 330 ohm resistor? I don't see any schematic with a button on it.

[mfalkvidd]

@NeverDie the sketch uses the internal pullup:

Button myBtn(buttonPin, true,  true, 40);				// Declare the button( pin, pullup, invert, debounce ms)