Impedance Analyzer Build and Experiments

[jaxbird]

...
the $99 is for an US student only ... otherwise it's $279
...

You can get them from MicrochipDirect for much less than that without being a student, plus I believe they run a campaign with free shipping this month. I'm sure I got an email somewhere, and that reminds me, I should order some stuff

Just don't get it because of this project, as I have no idea when I'm confident enough in the design and software to share.

Edit: to clarify, Microchip sells these for ~$220/each no matter who you are

[jaxbird]

New board ready:

[jaxbird]

Testing the extremes of the instrument. I've found this little 22nF Wima is very good to test the extremes in both frequency, sensitivity and linearity.

[jaxbird]

Measurement of 22nF from 1Hz to 20MHz, 10M to 10m range:



Much better than I had expected, I was expecting upper limit to be about 200-500k, but 5M+ is indeed possible.

[AlfBaz]

I'm curious, how long does it typically take to do a complete frequency sweep and analysis from say, 1Hz to 10Mhz and what is the minimum number of samples you would need for that range?

[jaxbird]

I'm curious, how long does it typically take to do a complete frequency sweep and analysis from say, 1Hz to 10Mhz and what is the minimum number of samples you would need for that range?

I haven't actually timed a full scan, the time depends on how low in frequency you want to go, anything below 10Hz is pretty slow. I always use the full 2x8k sample memory, but I do have some optimization, below 10 Hz I only sample 2 full waves, so that is 2 seconds+ per sample @ 1Hz, between 10 and 100Hz I sample 4 waves, 100 to 1kHz is 8 waves and above that 16 waves for the DFT. Retrieving the sample data and computing DFT plus various calculations for each sample is pretty quick,

For e.g. a capacitor measurement I rarely use anything below 100Hz, unless it's a large capacitor used in rectification.

In most cases 200 samples across the frequency range is enough to give a nice detailed measurement. It's what I use by default.

[jaxbird]

I've received a large number of private messages on this project while i've been away. It's always been my intention to release something at some point, whatever that means, but sometimes life happens, however I will post a video very soon explaining the functionality and I will make the design and software available free of charge, I hope my many hundreds hours of original work put into this project will be appreciated and not just copied into some shitty open source kickstarter like many before me or sold as original work on some shitty chinese site.

TLDR; I will post instruction video, schematics and software within the next week or so.

[dannyf]

great work, jaxbird.

not just copied into some shitty open source kickstarter

Likely that's where it is going.

Providing some hack-proof and visible signature in the software will help deter that.

[Wolfram]

I've received a large number of private messages on this project while i've been away. It's always been my intention to release something at some point, whatever that means, but sometimes life happens, however I will post a video very soon explaining the functionality and I will make the design and software available free of charge, I hope my many hundreds hours of original work put into this project will be appreciated and not just copied into some shitty open source kickstarter like many before me or sold as original work on some shitty chinese site.

TLDR; I will post instruction video, schematics and software within the next week or so.

Amazing work, looking forward to finally being able to make a decent impedance analyzer.

[jaxbird]

Would everyone prefer a kit available on eBay? (including pcb, essential high speed opamps, caps, shunts, cables and clips)

or just making a pcb themselves being ignorant of the essential knowledge how to achieve the best performance?

[jaxbird]

[fpliuzzi]

Your ebay kit idea sounds like an optimum way for a user, such as myself, to more easily mirror the quality measurement results that you have produced using your unit. I would certainly be interested in a kit containing the items you've listed above.

[jaxbird]

Small teaser:




I think I do need to add at least a little bit of input protection, perhaps a handful of BAV99 and some resistors.

[LaserSteve]

Considering your software looks an order of magnitude or two  better then the AD Demo board's included code, I'm highly interested. I work at a university and this chip would be the cat's meow for one of our small projects.  I have the demo board, and while the board is excellent. I have my doubts that the contract programmer knew what he was working on.

Steve

[fpliuzzi]

That's some teaser. Your Impedance analyzer software is pretty remarkable. You've really included quite a bit of flexibility into its operation.

[jaxbird]

Considering your software looks an order of magnitude or two  better then the AD Demo board's included code, I'm highly interested. I work at a university and this chip would be the cat's meow for one of our small projects.  I have the demo board, and while the board is excellent. I have my doubts that the contract programmer knew what he was working on.

Steve

Well, I'll release it for free once I have everything ready, just need to find the time to get everything together. I do contract work, but I doubt you'd find my rates reasonable .. especially if looking for a bargain. I mostly deal with very large corps where I really do need to factor in a lot of overhead, insurance, travel, meetings etc.

That's some teaser. Your Impedance analyzer software is pretty remarkable. You've really included quite a bit of flexibility into its operation.

Thanks, I did put a lot of effort into this project. I do think it's got a lot of potential, but sure, only a somewhat narrow audience.

[voltsandjolts]

This is fantastic jaxbird. Well done. 
Dave needs to do a review on this puppy when its complete, "young players" could learn a lot from this tool. And, ahem, some older players like me.

[rx8pilot]

This is a cool project. Wish I could have this right now.

[quarks]

 great project

[jaxbird]

This is fantastic jaxbird. Well done. 
Dave needs to do a review on this puppy when its complete, "young players" could learn a lot from this tool. And, ahem, some older players like me.

Thanks, I really find this tool has been very helpful in getting a better understanding of the relationship of many impedance related parameters, especially how to determine the quality of a capacitor, inductor etc.

I just wanted to make a usable ESR meter, but I kinda got caught up it in, and then The Electrician showed off his beautiful impedance analyzer, then that became my new benchmark, so I guess it's an unhealthy obsession coming to an end really. I'm proud of the end result though, I achieved or exceeded all the parameters I had for the project.

I have posted a video of the plug in board for those intersted.

[jaxbird]

New video, describing the plugin board and the design decisions involved:

[fpliuzzi]

I like the addition of the option to install SMA connectors on the input side of the PCB. It's always nice to be able to add an assortment of test jigs to a measurement device if needed. Nice touch.

[ruairi]

Fascinating project, thanks for the great video.

[jaxbird]

Fascinating project, thanks for the great video.

I like the addition of the option to install SMA connectors on the input side of the PCB. It's always nice to be able to add an assortment of test jigs to a measurement device if needed. Nice touch.

I will probably make a kit available, I think it will be around $50 including all parts (except the Analog discovery itself), it will work with both version 1 and 2 of the Analog Discovery and include everything including reasonable kelvin clips. I hope that is reasonable, I think it will cover the cost of all the parts with shipping from various vendors etc. It should not be a problem to solder the kit together for anyone interested, it's all 0805 or larger parts and so8/16 parts.

Shipping will be an additional $10 world wide. I will only be able to handle small quantities, but I think not a problem as the interest in this should be quite narrow. Anyway, the software if free for anyone who'd rather build their own, just keep in mind this is a hobby project so while I'll do my best to fix any bugs it might take a bit of time for me to respond to any bug reports.

I'll post another video on general usage and calibration of the device for best performance.

I'm sending one to Dave for evaluation, will be interesting to hear his opinion on the project.

[ruairi]

That sounds great, I'm in for a kit whenever they are ready. 

Thank you,
Ruairi