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Low-noise, Easy-to-use Analog Data Logger: SiGZiG

Captures signals at the lowest noise levels with very low drift. Precise and easy to use. It’s all your data logging fantasies come true.

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We are addressing the major frustration of collecting real world data such as pressure, temperature, flow, current, voltage and other analog signals. Having used dozens of data loggers during product development, we got fed up with their noisy/drifty signals, clunky and expensive form-factor, and the “Windows 95” user interface.

The SiGZiG makes it easier to tap into the analog world and log signals with precision and simplicity. Our 24bit model even has a noise floor of less than a microvolt. The software is cross platform with an interface that is simple and beautiful. The precision electronics are potted and encased in black anodized aluminum. Plug it into your computer via USB, connect up your sensors and you are collecting data in no time. (See full specs in the details section)

We plan to launch a Kickstarter campaign when the development is complete, you can sign up at Sigzig.com to be notified.


Demo Videos


How the Project Solved Our Specific Problem:

The SiGZiG is a byproduct of our hardware start-up which received funding from the Defense Department to develop advanced chemical sensors. To read data from our sensors the options were limited: 1) Ginormous data loggers or 2) Non-ginormous data loggers that didn't have the stability or true resolution sufficient to monitor our sensors or 3) Build our own.

Going with option 3 (by the way we tried 1 and 2 first), we successfully built hardware that was small, low-power, super low-noise, and very temperature stable. The hardware worked great for our chemical sensors as well as everywhere else around the lab. We love it, so we decided to package it in a nice case to see who else would want one too.

The idea is to use the SiGZiG to log precise changes in temperature for months or quantify the performance of your voltage reference. Anything that outputs a voltage can now be tapped into with a simple, easy-to-use tool. Had our data logger been available at the beginning of our project, it would have literally saved us more than a year of development time.

Function:

Our vision is to make this as simple and easy to use as possible. Plug in the USB logger, use standard jumper cables to connect things up and click start on the software you downloaded from our website (or write your own).

Specs:

We are working on three initial versions with more to follow:

4 Channel

4 Channel

8 Channel

18bit

16bit

24 bit

4 Differential

4 Differential

8 Differential

-5V to 5V

-5V to 5V and -10 to 10V

-5V to 5V

Noise @ 1 sample/s: < LSB

Noise @ 1 sample/s: < LSB

Noise @ 1 sample/s: 0.3uV

Drift: 15 ppm/C

Drift: 10 ppm/C

Drift: 2ppm/C

Up to 200 sample/s

Up to 200k sample/s

Up to 4k sample/s

Something that we started notice after playing with many commercially available devices is that their stated specs often didn't mean a whole lot. For example a product would state 24bit resolution but when testing it was really more like 16-18bit. All the components used matter to deliver the performance.

Our engineer Paul hooked a pulse sensor up to the 4 channel logger and here is his pulse taken from his index finger. You can see a cool plot of the test here:

Case

When designing the usb logger, we deemed the quality of the case as highly important to help with noise reduction, durability, coolness factor, and to reflect the internal build quality.While our first prototype cases came from Protolabs (great for quick-turn prototyping), we had to search for a more cost-effective solution for mass production.Working with different manufacturers on case materials, coatings, sandblasting, metal injection molding, machining, and anything else they/we could think of, we are getting some pretty great results.

One thing we thought would be cool is to make the bottom of the case customizable if you have a laser cutter/engraver. Here are a few designs that we came up with:


Modules

We haven't done any work on this yet, but we'd like to build modules to expand capability such as a

  • Voltage expander-12V to 12V,
  • Current to voltage10pA to 100mA, 1mA to 10A,
  • Screw Terminal adapter
  • Sensor Block – with luminosity, temperature, humidity, pressure, and color sensors.
  • BNC

Software:

Our original software was built specifically to test and evaluate advanced chemical sensors. It works great for our R&D but is limited to Windows, has a slow refresh rate, and is best for internal use. Here is a shot of it:

With the development of the this data logger, it became apparent that we must create a software package that is silky smooth and works across all desktop operating systems.

For the past 3 months, software has been built up with a focus on functionality. Here is the prototype:

It obviously isn't pretty, so we hired a graphic designer and this is the concept we like. We are currently skinning the prototype software:

Components and Software needed to get Started:

So what do you...

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  • Updated Data Logging Software Released

    Sigzig08/24/2015 at 17:49 0 comments

    This past week we spent a lot of time fixing bugs in the Zig-4 plotting software. You can download the data logging software on our website.

    Our previous project log describes our approach to software so I'll just let you know what was fixed in the latest version.

    Updates:

    • Resolution/Speed slider now works
    • Added zoom to the time scale
    • Graphical improvements
    • Detects Sigzig more reliably

    Check out the latest screen shot here of version 0.3a software.

  • Open Source is Amazing! Thank You @ProcessingOrg

    Sigzig08/20/2015 at 21:58 0 comments

    We just uploaded to our website our earliest attempts at creating an open source version of our full featured SiGZiG software that is used to interact with and collect data from our data loggers. This version will be limited to The Zig-4 hardware for now but may be adapted for more hardware in the future. We decided to take advantage of the Processing IDE and libraries to make this simple program and want to give a big thank you to all the hard work that is being done at processing.org. It is only because of the ease of use of processing that a simple program written by our engineer for logging during testing could come to rival our closed source (and expensive to make) version.

    It is not without bugs and glitches right now but we will be updating it frequently and will do some major fixes when our programmer gets back from vacation.

    We are also still working on some visual tweaks but it is coming along as you can see below:

  • So, what's in the box?

    Sigzig08/18/2015 at 23:47 0 comments

    Not too much technical information in this post, but it still involves something that is very important to getting a product shipped...packaging! I always love getting a package in the mail and opening it up to see all the goodies inside.

    Because this is a Hackaday Best Product entry, we wanted to show that this project is closing in on being an actual product ready to ship. When you open up a package from us, you will find a white box that contains the following:

    • Sigzig (of course)
    • 3 foot micro USB cable
    • Four 8 inch pin-out cables
    • Microfiber carrying bag

    Samples of these items were recently received at our location! You may be thinking, "why are you posting pictures of a plain white box"? Well, we are super excited to see the whole product and packaging coming together! Graphics for the box are being created so that these white boxes will have some branding in the future.

  • Processing Sketch to Collect Data

    Sigzig08/18/2015 at 23:42 0 comments

    We will be releasing a processing sketch soon for controlling the Zig-4 as well as collecting and displaying data from it. All of you are more than welcome to download it and give us your feedback. The idea behind making this program/sketch is that it gives you a base program to start from that you can then tweak and change to your liking or specific purposes.

  • It's not Just a Label

    Sigzig08/18/2015 at 23:13 0 comments

    It's not just a label, it is the label that your SiGZiG will don for the rest of its life. We are being extremely picky about the choice of supplier. The label is chemically etched stainless steel and we are looking at things like the quality of the etch (of course), the depth, the finish of the stainless steel (brushed, polished, etc.) and even the location of the tabs that are used to hold it during processing. Definitely not all suppliers are created equal as you can see in the comparison of various versions below.

  • Demo Video

    Sigzig08/18/2015 at 21:15 0 comments

    Here is our video demo for the HackaDay best product entry (this is now posted at the top of our project details page). We made this in Paul's basement at 2:00 a.m. in order to make the deadline.

    Unfinished basements are cold at night. Hope you enjoy it and that this gives you a better idea of SiGZiG.

  • Cases Update

    Sigzig08/18/2015 at 21:10 0 comments

    Cases are close to being finalized. Small changes, but we are detail freaks over here. The case on the left is our latest version. Slightly deeper black, bevel around the logo, and took care of some screw thread issues.


  • Manufacturing

    Sigzig08/18/2015 at 21:06 0 comments

    We've been touring assembly shops to find a manufacturer for our SiGZiG electronics. We looked inside and outside of Utah and landed on a good local shop so we can keep an eye on progress.

    Here is a quick snapshot of our tour.

  • Using Input Impedance to Measure Current

    Sigzig08/18/2015 at 05:59 0 comments

    Input impedance on measurement equipment is usually kept as high as it can in an effort to prevent loading down the signals the equipment is measuring. For example most general purpose digital multimeters aim for an input impedance of at least 1M ohm. The Zig-4 has a lower input impedance of 330k ohms but this is still high enough for many/most situations. That being said it is still important to understand input impedance and its affect on your measurements.

    In this post I thought it would be fun to actually take advantage of the 330k input impedance of the Zig-4 as a sort of low current sensing.

    The goal: To see if we can use the Zig-4 to detect a change in current in the very low nA range.

    Even though most everything can be calculated, I thought it would also be nice to back up some of the calculations using actual measurements. I wanted to use a recently acquired Keithley 480 Picoammeter and on the lowest setting so the first order of business was generating a really small known current.

    Using a 1G ohm resistor and a 1.25V voltage reference we can generate a current of 1.25nA.

    The resistor is 1% and the voltage reference is not exactly 1.25V plus the meter could be off a bit... but overall that's close enough.

    I then added a 100M ohm resistor in series with the 1G ohm resistor effectively lowering the current to a calculated 1.136nA

    Again, close enough.

    Now lets swap out the Keithley 480 picoammeter with the Zig-4 and do the same change in current to see what kind of signal we get. The current in both cases will be a little lower because now there is the additional 330k of the SiGZiG.

    Above is the setup except I switched back and forth between the 1G and the 1G+100M ohm resistor. Below you can see the signal I was able to get. The Zig-4 does have a small amount of programmable gain, so in all fairness the below plot is with it set to a maximum gain of 8 giving it more bits for the range it was measuring.

    So by using the input impedance of the Zig-4 to our advantage we can actually use it to monitor small changes in current down to the sub nA range. In the case above we were able to clearly pickup a change in current of only 115pA (113.5pA to be exact).

  • Zig-8 Prototype Testing

    Sigzig08/14/2015 at 05:59 0 comments

    Most of our focus has been on the Zig-4 lately but I finally found some time to play around with one of the Zig-8 (24 bit, 8 channel) prototypes to do some noise floor and short-term drift test. There is still a lot of work that needs to be done, but the results where still worth posting. Remember this is a Prototype!

    The setup of the test was basically take three pretty good voltage references, put them on the bench and monitor them along with a temperature sensor and a silver oxide battery (one of the original voltage references) for 10 hours once a second. Not overly scientific but educational nonetheless.

    Below is a plot of the three Vref's. This is a 1 hour section after about 6 hours of warmup (you can see the time stamp at the top). Even though a sample was taken every second there is a little aliasing going on with the way the software displays all the data so you don't actually see every point (sorry).

    The scale on the left is in µV and all the plots have been zeroed out for easy comparison. So what do we see? Well we are basically looking at the combined noise and drift of the SiGZiG Zig-8 prototype with the noise and drift of the 3 voltage references. And it looks like, at least over 1 hour, that the combined noise and drift stays pretty much within +/- 1µV. So what part of the noise is from the Zig-8 prototype and what belongs to the voltage references?... well the short answer would be that generally any signal common to all the readings is from the SiGZiG. That being said there are other things in common, like temperature (for good or bad).

    Lets do some averaging to see if we can better pick out the common signal.

    The above data has been smoothed with a running average of 10 samples. You can kind of make out parts that are in common to all three plots.

    Okay, this 60 min chunk is getting boring, lets look at the whole thing.

    As you can see not all voltage references are created equal. Now if you look at the yellow plot the real question is which voltage reference is drifting, the one being measured or the one in the Zig-8? Well if I was only measuring the yellow one it would be pretty hard to say, hopefully now you can see the wisdom in measuring more than just one supposedly great voltage reference. By monitoring more than one it becomes a statistics game and in this case the yellow one is the odd one out.

    Applying averaging again and you can start to make out the commonality between signals. However looking at what is common is still not a perfect method for recreating the noise and drift signature of the SiGZiG because there are slight variations between each channel as well as the fact that each channel is not sampled at exactly the same moment in time. Overall though it still gives a much clear picture than just monitoring a single voltage source when down at these small levels.

    So how did the silver oxide battery compare?

    Actually not that bad, we are talking 140µV of drift over 10 hours. Even so it definitely puts the others in perspective.

    And what about temperature?

    I noticed some of the changes in temperature seemed to match up with variations in the voltage of the silver oxide battery.

    After scaling and overlaying you get this

    If you had a good enough data logger you could almost use a silver oxide battery as a temperature sensor!... okay no you couldn't but you can obviously see it is affected by temperature.

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Discussions

Roobotics wrote 04/22/2017 at 22:03 point

I guess this product is dead? Did it ever sale any? Maybe I missed a kickstarter. As John said, website is down(random redirects possibly to spammy/malicious places), official twitter no activity since 2015, unfortunate, I wanted to buy one for a logging project.

  Are you sure? yes | no

John Boyd wrote 01/15/2016 at 21:09 point

What is the latest? I have been waiting for this to go on sale, but just saw the website is down.

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K.C. Lee wrote 07/30/2015 at 19:24 point

My free comment of the day:

If you want to sell stuff, better have the actual numbers to back up what you are selling to a technical crowd.

>The idea is to use the SiGZiG to log precise changes in temperature for months or quantify the performance of your voltage reference.

Keyword: months.  And yet you have not posted the long term drift specs of your data logger.   How do we know what you are observing changes in the voltage reference isn't due to your instrument accuracy over time?  (i.e. components aging etc)  There is a reason why instruments needs to be calibrated/recertified periodically.

>For example a product would state 24bit resolution but when test it was really more like 16-18bit. All the components used matter to deliver the performance.

So where is your actual ENOB, linearity figures then? 

Not sure about anyone else, I actually like the non-skinned plots better.  May be I care more about functionality over form.

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Sigzig wrote 04/07/2015 at 21:05 point

That's why we posted here, we know what we want but we need feedback/comments from you to know what everyone else wants. Yes, the main hardware is closed source (so people can work full-time on it), but come on guys, this is Hackaday!... I am pretty sure someone on here will do a full tear down, especially when you think about the number of post on depotting, decapping and general reverse engineering.  

The other main reason for posting is as mentioned "open source adapter boards."  We already have a bunch in the pipeline that we are going to post all the files for and hope others will join in with even more.  

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haydn jones wrote 04/07/2015 at 14:03 point

I believe Amtel have posted a project that uses there close source chips. Its also cool to see projects develop to the production stage, even if we can't get to see every detail.

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zakqwy wrote 04/06/2015 at 19:33 point

Cool! Looks useful. I want to build one!

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davedarko wrote 04/07/2015 at 09:37 point

defense department vs. open source? muah-ah-ah, guess that won't happen because of NDAs etc. . This project kind of fits your .stack page @zakqwy, hope they will add some "open source adapter board" projects here, but why share a closed source project if not for advertising reasons only :( It's a cool data logger that was already featured on hackaday.com and the person{s} who build this definitely deserve some credits for the logger. 

http://www.sigzig.com/blog/2015/1/26/answering-data-logging-questions&nbsp;

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zakqwy wrote 04/07/2015 at 13:47 point

Yeah, I'm starting to get more shameless with my trolling of closed-source projects. I really do like the product too, it's just not appropriate for this community if it's not open-source (IMHO).

Okay @Sigzig, a real question--any plans for a multichannel 4-20mA input module? If you want to appeal to industry, $40 "temperature and pressure sensors" aren't going to fly; you need to interface with transmitters.

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davedarko wrote 04/07/2015 at 13:54 point

yup, feel the same way, too :) 

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Sigzig wrote 04/07/2015 at 21:32 point

is there a specific purpose for the 4-20mA range?  We could do  1mA-1A or something like that.  That would give you resolution down to the low uA range.  In our lab we use a log compressed 10pA-10uA for our chemical sensors.  

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zakqwy wrote 04/07/2015 at 21:46 point

In the world of industrial field instrumentation--flow meters, temperature sensors, level transmitters, gas analyzers, etc--24vdc/4-20mA current loops are the gold standard and have been since they took over from 3-15psig air signals half a century ago. Some instrument manufacturers try to push advanced digital protocols (such as Foundation Fieldbus and Profibus), but the vast majority of facilities I come across (upper Midwest) still use current loops for remote indication, control, and logging. 

1mA - 1A would cover the range, and low uA resolution would certainly be adequate for industrial datalogging. However, you'll find that customers in the instrumentation sector will often specifically ask for a 4-20mA system--it's the only thing they've known in a lot of cases.

This might not be relevant if industrial instrumentation isn't a market you want to pursue. However, I've been in that world for some time and there is a distinct lack of good, cheap, compact, rugged, easy-to-use dataloggers out there.

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