Chinese Timegraphers

[mikepilk]

1 hour ago, ManSkirtBrew said:

I also really like the fact that you can see the raw waveform of what the microphone is hearing in real time.

I have a Weishi 1000. I'm interested in one of these to have the raw waveform to help in fault finding.

[JohnR725]

3 hours ago, Kalanag said:

My version is not a 3D printed „prototype“ anymore but industrially injection moulded.

That's a very helpful clue because I'm not sure how we can tell the good one from the previous ones if they basically look the same?

3 hours ago, LittleWatchShop said:

Interesting.  It digitizes the signal and sends it over USB.  This is in contrast to the other solutions talked about around here where the signal goes into the audio port.

I was trying to mentally grasp what the big chip was and then I realized how stupid of me that's the audio processing chip. They basically is integrated everything together on one circuit board which is definitely a good idea. It's not unique though but what's unique is its all in one circuit board. I found variations with the various laptops I had and I hate batteries and having to remember to turn the thing off. So I was using a little preamp with a USB sound soldered together this is a much nicer solution though. Plus the price is now definitely worth getting.

Then how do curiosity I looked at eBay sure enough the prices dropped and which one to get? Classic problem with Chinese variations. It looks like they still have the old style ones you're looking for the one with the USB cord. Then some of them are in slightly different plastic cases but go to the listing and go through all the pictures and classic they show a square case but then they eventually show the same case style is the one up above. Then of the four sellers in the US I picked one that had at least a slightly better well less negatives than all the rest. I'll take a leap of faith that it might actually show up and be technically correct. As this will save the problem but I currently have of I was going to make a new circuit board for the one that I have an integrate everything together and this will solve that problem. So I'll let you know what a couple weeks when it arrives and whether it actually comes from the US war wherever it comes.

[LittleWatchShop]

I want to know what chip they are using.  Maybe on yours they didnt paint over the markings.

[Kalanag]

30 minutes ago, LittleWatchShop said:

I want to know what chip they are using.  Maybe on yours they didnt paint over the markings.

CM108 is a USB Audio I/O controller.

CM108 spec

The second chip is a LM386 audio amplifyer.

LM386 spec

Edited January 9, 2023 by Kalanag

[JohnR725]

4 minutes ago, Kalanag said:

CM108 is a USB Audio I/O controller.

CM108 spec

I see you beat me to the answer. I was Going to suggest even if the part number was sanded off you can just look in the configuration file and probably figure it out. Then for my amplifier upgrade I was switching USB devices and the one I was switching to that is the chip so it should be a good ship about the only concern I could have is it would be nice if it was in a shielded box. But if that becomes an issue I can deal with that.

[LittleWatchShop]

4 hours ago, mikepilk said:

I have a Weishi 1000. I'm interested in one of these to have the raw waveform to help in fault finding.

That is indeed a good thing.  When I want to see the raw waveform, I have to leave the LWS and go into Lab #2 and put it on my watch amplifier and observe with an oscilloscope.  A bit of a pain.

I am working on an alternative.  I have the parts to put an inline splitter on my W1900 and I have a spare Tek digital oscope that is not being used.  It is small enough to find a home somewhere on the watch bench...I think ???

But wait!!!  Maybe there is a better oscope solution that takes much less space.  I see it cheaper on ebay.

[Vinito]

I just now ordered one of those mic base things at $32.

I previously bought some of these thinking I'd 3D print a case apparatus for it, which I'll probably still do at some point. If it worked (big "if"?), it would be a cheap way for folks to have a mic. But the pre-made one, even though it won't arrive probably until next Christmas, might still get to my bench before I build the DIY one 

 

[Kalanag]

10 hours ago, LittleWatchShop said:

That is indeed a good thing.  When I want to see the raw waveform, I have to leave the LWS and go into Lab #2 and put it on my watch amplifier and observe with an oscilloscope.  A bit of a pain.

May I ask why you don‘t just use the oscilloscope function of Tg0.5.0 for free?

Edited January 10, 2023 by Kalanag

[mikepilk]

Tried to get one on Ali-express, but non will ship to the UK 

I haven't use Ali-express before - is there a way to only show results for those who will ship to your country?

(And the search seems odd - never get the same results twice!)

[lexacat]

59 minutes ago, mikepilk said:

Tried to get one on Ali-express, but non will ship to the UK 

I haven't use Ali-express before - is there a way to only show results for those who will ship to your country?

(And the search seems odd - never get the same results twice!)

Oh, don't get me started on Ali X search, let alone their filter function. That's completely broken.

You should be able to set your shipping preferences up the top:

[Kalanag]

https://www.aliexpress.com/item/1005004815700149.html?spm=a2g0o.productlist.main.17.6f083c6ccWU1PN&algo_pvid=106ce219-d79e-48c0-b91a-aa5e4b6dddd0&algo_exp_id=106ce219-d79e-48c0-b91a-aa5e4b6dddd0-8&pdp_ext_f={"sku_id"%3A"12000030596764541"}&pdp_npi=2%40dis!GBP!39.44!23.27!!!!!%402100b18f16733472240287863d070b!12000030596764541!sea&curPageLogUid=lZHOkSLRDXL3

[lexacat]

5 minutes ago, Kalanag said:

https://www.aliexpress.com/item/1005004815700149.html?spm=a2g0o.productlist.main.17.6f083c6ccWU1PN&algo_pvid=106ce219-d79e-48c0-b91a-aa5e4b6dddd0&algo_exp_id=106ce219-d79e-48c0-b91a-aa5e4b6dddd0-8&pdp_ext_f={"sku_id"%3A"12000030596764541"}&pdp_npi=2%40dis!GBP!39.44!23.27!!!!!%402100b18f16733472240287863d070b!12000030596764541!sea&curPageLogUid=lZHOkSLRDXL3

Those are a really good option for sure.

If you're definitely after afull timegrapher I've found this one:

You need to be REALLY careful with Ali Express, because the "landing picture" and the product you get don't always align (or never align, in my experience). Take this screenshot for example. The landing picture is a standard weishi no. 1000 in white, but the red square is the actual selected product. It's black:

 

[LittleWatchShop]

3 hours ago, Kalanag said:

May I ask why you don‘t just use the oscilloscope function of Tg0.5.0 for free?

Physics. Two objects cannot occupy the same space at the same time. I just don't have the room for a PC in the LWS. I have an old Nuc that is small enough, but then keyboard, mouse, monitor,  cables...

Yeah, perhaps a dumb reason...

[mikepilk]

1 hour ago, lexacat said:

Oh, don't get me started on Ali X search, let alone their filter function. That's completely broken.

You should be able to set your shipping preferences up the top:
 

I have the shipping options set to UK, and the items do say "Ships to United Kingdom", but at checkout I get

1 hour ago, Kalanag said:

https://www.aliexpress.com/item/1005004815700149.html?spm=a2g0o.productlist.main.17.6f083c6ccWU1PN&algo_pvid=106ce219-d79e-48c0-b91a-aa5e4b6dddd0&algo_exp_id=106ce219-d79e-48c0-b91a-aa5e4b6dddd0-8&pdp_ext_f={"sku_id"%3A"12000030596764541"}&pdp_npi=2%40dis!GBP!39.44!23.27!!!!!%402100b18f16733472240287863d070b!12000030596764541!sea&curPageLogUid=lZHOkSLRDXL3

If only I could buy it !

[lexacat]

16 minutes ago, mikepilk said:

I have the shipping options set to UK, and the items do say "Ships to United Kingdom", but at checkout I get

If only I could buy it !

Well that's just weird. It might be specifically the address you've set. Are you sending to a non residential address, PO Box, or something else non-standard? Try changing the address if you can and see if the checkout works...

[mikepilk]

46 minutes ago, lexacat said:

Well that's just weird. It might be specifically the address you've set. Are you sending to a non residential address, PO Box, or something else non-standard? Try changing the address if you can and see if the checkout works...

It's just my home address. I deleted it, and all cookies but I get the same whatever I try. Very annoying

I just downloaded the app to my phone - same problem !!!  grrrr

GOT IT !

When I registered with Ali Express, I let Google auto-fill the address. Seems it didn't like it. I deleted it, entered it all manually and it finally worked. Import tax to pay, but still only £27

Edited January 10, 2023 by mikepilk

[LittleWatchShop]

15 hours ago, Kalanag said:

CM108 is a USB Audio I/O controller.

CM108 spec

The second chip is a LM386 audio amplifyer.

LM386 spec

I just ordered this for essentially ten bucks.  All it needs is a piezo and a case.  Will report back.

[xyzzy]

4 hours ago, LittleWatchShop said:

Physics. Two objects cannot occupy the same space at the same time. I just don't have the room for a PC in the LWS. I have an old Nuc that is small enough, but then keyboard, mouse, monitor,  cables...

Yeah, perhaps a dumb reason...

Laptop?  Ought to be able to use a Linux tablet too, like this https://www.pine64.org/pinetab/  The keyboard is removable.  Tg gives you a lot more than just a scope, no need to switch between timegrapher and scope.  Use less space than the weishi alone with a better screen.

3 hours ago, LittleWatchShop said:

I just ordered this for essentially ten bucks.  All it needs is a piezo and a case.  Will report back.

I wonder how the timing accuracy is on the CM108?  All the software I've seen uses the audio sample rate as the reference time.  They allow calibration, and tg might even get continuous calibration with NTP, but still if the audio sample rate is not constant, this shows up as errors in the s/d.

The cm108 requires a 12 MHz clock crystal, so I assume it generates its own audio and USB clock.  USB spec is ±0.25% on the clock.  Something you see now is crystal-less designs with just an on-chip RC oscillator, which is not good enough to meet 0.25%, but they use the USB SOF signal from the USB host to synchronize a PLL.  I've read C8051F32x does this, but who knows anything about that chip?

The sparse CM108 datasheet also says it uses adaptive mode.  This relates to how USB audio rate is controlled and so it important for timing accuracy.  What this means is it will attempt to modify the audio clock rate to match rate at which the USB host consumes data.  But, how does it do this?  One way is have an audio buffer with a fill level that is measured.  If it starts to fill up, audio is being produced too fast and the audio clock is slowed down.  This clock could be slowed down by having a fractional PLL with a few steps near the normal rate.  It can slow down one step.  But this might be too slow.  So the buffer empties and now the rate must be increased. 

So you get an audio rate that shifts back and forth between different rates.  An example might be 47619 Hz, 48000 Hz, and 48387 Hz.  I got from an NXP app note. What's that mean in s/d?  It's 685 s/d slow to 691 s/d fast.  That would be pretty useless!

One hopes the CM108 can steer the PLL in a closer tolerance than that!  One could probably measure it on the ADLRCK pin, assume the external I2S interface runs on the same clock as the internal ADC, which is probably does.

[LittleWatchShop]

4 hours ago, xyzzy said:

I've read C8051F32x does this, but who knows anything about that chip?

Well, I was one of the designers--it was my company.

See patent: US7505540.  There is no PLL involved in this invention

Edited January 10, 2023 by LittleWatchShop

[xyzzy]

Really!  You've never mentioned this before.  Certainly not on page 10 of this thread.

It looks like the that chip does do clock recovery.  No PLL in the diagram.  I guess it tunes the trim capacitance or something like that?

The CM108 does not come with nearly as nice of a datasheet, so we don't really know what it does.  I didn't see a spec on the 12 MHz crystal, so one can't even infer it from that.  If it was 0.25%, then we could guess it doesn't do any kind of clock recovery, while if it was greater than it probably would need to.

[LittleWatchShop]

4 minutes ago, xyzzy said:

Really!  You've never mentioned this before.  Certainly not on page 10 of this thread.

Well, nobody asked!!  Actually, though, somewhere on this forum I noted that the Weishi uses a Silabs micro and that it was one of my products (Silabs bought my company).

You are correct about how the chip works.  It is a pretty stable RC oscillator that is tuned from the USB burst. 

[JohnR725]

7 hours ago, LittleWatchShop said:

just ordered this for essentially ten bucks.  All it needs is a piezo and a case.  Will report back.

Strangely enough I have one of these well to be technically correct I have two of them. For future projects that may or may not ever get finished. Just a reminder this is basically equivalent to the audio into your laptop or computer it just puts it into a USB device.

That means you're going to need just a little more than the piezo Unit something to match Impedance usually possibly a little amplification may be some signal processing. Personally I find an op amp works really well for this providing you pick and choose the right one and then you can powered That off the same power as the USB powering this device and toss your batteries away.

[LittleWatchShop]

21 minutes ago, JohnR725 said:

Just a reminder this is basically equivalent to the audio into your laptop or computer it just puts it into a USB device.

Yup, I realized that.  But because USB is coming to the sensor box, you get the five volts to build your audio amp/filter for free.  My piezo amplifier/filter has a FET input.  The rest is discrete BJTs.  In retrospect, it is overkill but I was having fun when I designed it and laid out the board (also too big, but I did not want to mess with SMDs for a prototype).  When mine arrives, I will probably put it in the same place you put yours!! 

[xyzzy]

2 hours ago, JohnR725 said:

For future projects that may or may not ever get finished. Just a reminder this is basically equivalent to the audio into your laptop or computer it just puts it into a USB device.

There is a difference.  With this device, there are two clocks.  One is in the device, it samples the audio.  For a computer, you are done here, one clock.  But with the USB device, the audio must be sent over USB.  USB is digital, there is a clock here too.  But this clock is in the computer.

Both clocks must agree: every second, 48000 audio samples.  But are two different clocks going to run at exactly the same rate?  No, they are not.  So stuff must be done about this.

And that stuff to deal with these two clocks that must be the same but aren't, it can affect timing things via audio at a rate measurable in s/d.

[JohnR725]

4 hours ago, xyzzy said:

There is a difference.  With this device, there are two clocks.  One is in the device, it samples the audio.  For a computer, you are done here, one clock.  But with the USB device, the audio must be sent over USB.  USB is digital, there is a clock here too.  But this clock is in the computer.

Both clocks must agree: every second, 48000 audio samples.  But are two different clocks going to run at exactly the same rate?  No, they are not.  So stuff must be done about this.

And that stuff to deal with these two clocks that must be the same but aren't, it can affect timing things via audio at a rate measurable in s/d.

So simplistically are saying that using a USB interface for timing is out?