Hi All!
The Joulescope JS110 Precision DC Energy Analyzer launched today on
Kickstarter.
Joulescope is the most affordable and easy-to-use tool that enables you to create better, more energy efficient products. It measures current from 3A (10A bursts) down to nanoamps and voltage up to 15V. A few features set Joulescope apart:
- Dynamic range: 10 amps down to nanoamp resolution
- Low voltage drop: 25 mV @ 1A (20 mV max across shunt resistor up to 2A)
- Great bandwidth: 250 kHz bandwidth with 2 MSPS
- Easy to use: Simple multimeter view and more detailed oscilloscope view with waveforms over time
- Customizable: Host software is open source. Swappable front panel is also open source!
- Portable: Light and small - can travel.
- Affordable: $499 on Kickstarter ($449 early bird) with $799 retail price (USD)
I started a Joulescope topic under
Test Equipment to discuss the technical details.
Let me know what you think, and I'm happy to answer questions!
@Evi - sorry you do not see the value. Hopefully, Dave will do a proper teardown so you can see that Joulescope is fairly priced. People developing battery powered products with high dynamic current range (pretty much anything that goes to "sleep" and has RF, displays, LEDs, or motors) either buy products that cost more than 10 times this, or use more manual techniques that use much more time. I wrote a more detailed blog post on the
alternatives here, and you can also check out
embedded.fm where we chatted about these issues.
You can think of Joulescope as the Saleae Logic of energy measurement. It's not the first, the cheapest, or the most accurate, but it's the one that is simultaneously affordable, easy-to-use and accurate enough for board-level voltage, current, power and energy measurements.
Quite amazing specifications; I wonder if the large banana plugs may introduce too much noise to nA or 10s of uV to the measurements.
I didn't yet see the video nor read the entire documentation - will do that later.
The price seems alright if the software is well polished and the noise is kept at bay.
@rsjsouza: Thanks! I have been working to achieve these performance specifications for two years, so it's not easy!
Yes, the banana plugs and individual wires do pick up more noise than BNC + coax, for example. In the process of developing Joulescope, I started with banana, then went to BNC, then realized I couldn't win. BNC + coax is limited to about 2 A, and even then introduces a significant voltage drop. The BNC connectors also have a much higher resistance than banana plugs. The good news is that many applications don't care as much about bandwidth at very low currents, so the additional noise picked up by banana plugs + wires doesn't matter too much (still keep cables short).
For situations where noise pickup does matter, you can swap out the front panel! The front panel hardware design is open source and available on
GitHub. I already have a BNC front panel and USB 2 front panel. I will be offering these as part of the Kickstarter somehow (hopefully a good stretch goal), and I will work with the backers to see what they want!
The Joulescope User Interface is already easy to use and functional. I will be adding more capabilities to improve the value. I have received great feedback from the Joulescope beta users and Kickstarter community. I maintain a list of
future features. Joulescope backers will help guide development, so
join the community!
It is isolated, excellent!
What is the rated isolation voltage?
Quick suggestion: make it SMALL.
Thanks for the feedback! Joulescope is pretty small. 150 x 81 x 33 mm and 217 grams. That's as small as its getting for this version and way better than any competing instruments. This precision analog and isolation takes up space!
What is the rated isolation voltage?
The rated isolation voltage is ±48V. I think that covers a majority of the use cases and means that I don't have to deal with much more stringent CE/UL testing. However, the actual components are rated much, much higher. The aluminum case also prevents higher isolation voltages. Do you have a specific isolation voltage requirement in mind for your application?
No immediate need, I was only wondering, perhaps you should post it on the specs.
Thanks for your reply.
Just out of curiosity, did you use those TI DCP power modules? I can't think of how did you get the 48V limitation from other than that.
The ±48V rating is self-imposed. It qualifies Joulescope as a very low voltage device so that it should get through CE certification easily, and UL is not necessary. The actual components are:
| Part # | Mfgr | Description | Isolation:working | Isolation:60s | Isolation:1s |
| 760390014 | Wurth | Transformer | 400 VRMS | 2500 VAC | 3125 VAC |
| Si8661BB-B-IS1 | Silicon Labs | Digital isolator | 445 VRMS | | 4500 VRMS |
| TLP2361(TPL,E | Toshiba | Opto isolator | 500 VRMS | 3750 VRMS | |
The Joulescope PCB maintains a 4 mm clearance between the isolated sensor side and USB side. The real limitation for isolation clearance is the aluminum enclosure. If I end up with enough customers that want to use Joulescope with higher isolation ratings, I can design a suitable enclosure and get the safety certifications. The ±48V rating is already in the user's guide, but these details are not. I will add them! Thanks!
So it's basically a Mooshimeter with more resolution and more bandwidth. (And a higher price.)
Thanks for posting the VoltLog Joulescope teardown & review. Hopefully, Dave gets around to one sometime!
Joulescope has much higher bandwidth, much better resolution, much better accuracy, much higher input impedance, with software that makes it simple to measure and optimize energy consumption. Joulescope also transfers all 2 MSPS, not just periodic summaries, which really matters for measuring short events like interrupt service routines, inrush current, and firmware changes that affect the duration of power states.
Joulescope takes care of measuring correctly so that you can focus on your work that matters. You can think of Joulescope as the Saleae Logic of energy measurement. It's not the first, the cheapest, or the most accurate, but it's the one that is simultaneously affordable, easy-to-use and accurate enough for board-level voltage, current, power, and energy measurements. Joulescope is also way more affordable than anything with comparable specs. You can download the
Joulescope User's Guide which contains the specifications.
@Evi - sorry you do not see the value. Hopefully, Dave will do a proper teardown so you can see that Joulescope is fairly priced.
I have the unit sitting on my Mailbag shelf.
BTW I'm actually working on very similar design (new and vastly improved uCurrent).
I have the unit sitting on my Mailbag shelf.
BTW I'm actually working on very similar design (new and vastly improved uCurrent).
Hi Dave!
Great to hear that a Joulescope is on the shelf ready for your mailbag segment!
Sorry to hear that Joulescope might be competing with your new project. :-/ You've done a great job teaching about burden voltage and dynamic current range. I am sure you will give the Joulescope a fair look either way. The existing products in $250 to $1000 USD price range for energy measurement are lacking, and there's room for a few good products.
Hi
Could you consider writing a post on how you managed your Kickstarter campaign? Seeing a small niche technical product doing so well is awesome. I think your input would help many folks doing the same thing.
Thank you
Could you consider writing a post on how you managed your Kickstarter campaign?
Yes! I definitely want to write more. I have some journal entries, my notes and some brief posts to a private forum. I won't have time to write publically for another few weeks though (need to get Joulescope over the manufacturing hump), but I will post here when something is available.
That would be awesome. Please do notify me in case it did not come under my attention.
We have now shipped Joulescope to all Kickstarter backers and preorder customers. We delivered according to the original Kickstarter timeline, and we are happy to announce general availability for Joulescope.
To order a Joulescope, visit the Joulescope shop:
https://shop.joulescope.com/A HUGE thank you and shout out to all of our backers and the growing Joulescope community!
