Greeting from ZSCircuits!
We are pleased to launch a new product ZS1100A (IOT Power Meter). This is an advanced version of the IOT power profiler with an in-built power supply. So the users can directly power their IOT devices with this, and measure the power consumption. It has better accuracy and slightly higher dynamic range compared to the ZS2102A. We are launching it at CrowdSupply.com at a pledge price of $499 + shipping as applicable.
Link for the crowd funding page
https://www.crowdsupply.com/zscircuits/zs1100a-power-meter
Note that the product is still under prototype stage and shipping will happen only by Oct 2020. The price is limited to first 100 backers only and the products are shipped directly from the USA to worldwide.
@Julian Higginson : Thanks for your support in the crowd funding. Our goal is to make this tool available to all IOT developers around the world and help them optimise their designs. Your contribution will go a long way to realise this.
Regarding API, this is in one of our lists. Once the hardware is out in production, we can focus on writing the APIs.
an exponential function would make the most sense to me, but I also appreciate that's a lot harder to do. Identifying critical features and finalising their parameters for a product is always a tricky thing... this is why I was just asking what the capabilities were rather than trying to demand new features. To be honest, the area where I'm more concerned with output impedance is smaller batteries like the CR2032. The resistance you'll see from big batteries isn't usually going to be a limiting factor for pretty much anything I want to do. (And depending on what you're actually doing here to realise this feature, you might find the heat dissipation in an emulation resistor to be a big problem even for low resistances once the supply is pushing its current limits) But that said - I'm more than capable of adjusting whatever you ship to suit my usage if it's possible... particularly if it's supported and encouraged. :-) And even if I can't modify the unit itself, I can run the supply to a basic open load output level at whatever state of charge I want to investigate, I can always just put a resistor inline with my DUT anyway... the most I'd be missing there is recording the voltage drop in the application and being able to see it change over sustained end of life discharge. But this kind of edge behaviour is something that's easy enough to investigate for a set charge state. Another option, is if you had an API to allow integration of your application with other software, then it would be easy enough for me to make my own digitally controllable resistance to suit myself, hook it up by its own USB port, then write a really simple python program that just read the battery state of discharge from your application, and drive the impedance from there. So many possibilities really. Maybe better not to risk too much right now.... Whatever you come up with, my order is placed, and I'm looking forward to having this massive improvement over the nordic power profiler that I've been using most recently
The digital pot used to set this has only 256 taps and having 100 Ohms would increase the resolution by a factor of 10. We think 10 Ohms should be sufficient for most of the batteries. Anyway the hardware would be open source and the users may be able to swap few resistors to get higher resistances, if they need it.
We would release the documentation on how to do that.
In the meanwhile we would check if we can get some kind of non linear function to have higher steps as the output resistance increases so as to get the max value to 100 Ohms, while keeping the 256 steps.