CurrentRanger review & availability

Sunday morning I woke to an unusual amount of email asking about the CurrentRanger availability. And the limited stock was all gone, so I knew something happened.

I was then pointed to to Andreas Spiess’s latest video:

Thanks to Andreas for posting a thorough review of the CurrentRanger, I especially appreciate how he was able to quickly tune the code to his own needs and customized the CurrentRanger to behave the way he wanted.

He also kindly posted a 3D printable model of the case he shows in the video, some folks already printed it and it looks great! Find it on thingiverse here. The stock case needs some modification to fit the green terminal and access to the USB case, as well as allow mounting the buzzer. If you have a 3D printer you can print this case and keep the black stock case for another project, thanks Andreas!


I am working to get more units in stock this week. There are a lot of moving parts to making this product. First a large BOM and a complex assembly and testing procedure. I want to ensure to the best of my ability that each unit is able to deliver what it claims.

Some components like the banana jack terminals and OLEDs come from the place we hate to love, China. I’m currently waiting for the small banana jack terminals and OLEDs. However I have a surplus of GOLD terminals, and could replace the small terminals with those if some folks are interested – let me know!


I can understand concerns about the cost especially for hobbyists or students. Let me reiterate what I’ve already mentioned in the forum and to others. Here’s the TL;DR of that:

I always tend to design something that I would first and foremost use. While not a high end product, this is not a toy either. I spent over a year – among other things of course 🙂 – developing this product and I put a lot of thought into pricing it before release. I’m not interested in selling high volumes at razor thin returns on my investment and my effort. I prefer fewer sales for people that can appreciate it and not abuse it. I think it was priced fairly, given the high cost of the BOM and the complexity and time it takes to make and test, it really is probably the most complex thing I ever made both in hardware and software. Also, it is not much more expensive than the uCurrent, I am sure anyone reasonable who understands the differences and the set of extra features (perhaps watched the video above for some contrasts), can appreciate all that for just $30 more. The uCurrent is always a great option for those needing accurate current measurements at a lower price.

1 thought on “CurrentRanger review & availability

  1. If you work with wearables, or any device that strives for a low-power budget, then measuring nA is vital to knowing your code is really saving every drop of power, especially when the uC is sleeping.

    Current Ranger (CR) is a neat piece of kit. I use it to measure minimum sleep current on Nordic’s nRF52 uC. If you use an Agilent (or equivalent) DVM capable of nA to mA current measurement, then you will have paid some serious money, perhaps a few K for it, and probably you forget how to work it between projects. It sits on the shelf depreciating…

    For the hobbyist/semi-pro, the CurrentRanger(CR) is a brilliant, inexpensive alternative. It takes but a minute to set up and get measurements. If you are on the road a lot, it fits in a corner of your carry-on.

    It’s predecessor, uCurrent-Gold, by Dave Jones’ of EEVBlog fame, of which I have two, works fine and is a great little tool, but it’s a tiny bit tedious to use. With uCG you have to keep manually switching it’s range switch as the uC alternates between normal operations (mA), and deep sleep (a few 100 nA). Added to that is the need to sometimes switch ranges on the attached DVM – it takes some juggling. And between sessions, the uCG battery inevitably goes flat, and you have to dissemble the enclosure to replace battery.

    Felix’ CURRENT RANGER ** STREAMLINES** the process in three important ways.
    1) It automatically switches range between mA, uA and nA;
    2) It has it’s own (optional) display – pay the extra, it’s more than worth it;
    3) It uses a LiPo that you can charge using a standard USB PSU with taking the LiPo out the enclosure.

    Felix made valuable, experience-based improvements that more than offset the extra few bucks. He also responded to all my questions very promptly with useful advice, and support.

    Disclosure – I’m not related to Felix, I have not met him, and I’m just a regular customer, and I rarely write testimonials, but I swear this is the device I have been waiting for.

Leave a Reply

Your email address will not be published. Required fields are marked *