Velleman WFS210 wireless oscilloscope for only £20 !

[Mr. Scram]

I will waste no time and request a refund.

I am prepared to deal with a sub-quality product as described in the forum, where the fun comes from messing around with the firmware.

But I am not in the mood of having to deal with a DOA device.

It seems, however, Amazon requires me to ship back the defective device: this is OK if Amazon pays for the expenses. Otherwise it is kind of pointless and that would mean I NEVER would buy anything else from them.

I will keep you updated.

Regards,
Vitor

Please try to get it to work first. I thought I had a dud too, but with some love and attention, I have gotten the thing to work nicely. Maybe yours is different, but it certainly isn't a device that's ready to out of the box every time.

[Specmaster]

I just got mine to do a test and the answer is yes, the wifi light does come on if the power button is pressed while it is charging BUT that might not be the case if the battery is dead flat in the first place. It might be worthwhile leaving in on charge for a couple of hours and testing it again to be certain that it is DOA

[Bicurico]

I'm already on the Amazon support chat, requesting a replacement.

I am pretty sure this one is a DOA/DUD, because apart from the charging LED's nothing happens. I would wait/investigate if a WIFI LED would go on, but like this it could be anything from dead CPU to lacking firmware. It is just a paperweight right now.

Also, the fact that the box came unsealed, the inner plastic had the scotch tape broken and the screws under the feet where not fully screwed in, indicated that someone else struggled with this before...

[Avacee]

From a dead flat battery I plugged it in and turned it on and the wi-fi LED started flashing immediately and I was able to connect to it.

Just in case your wi-fi LED is kaput can you search for a wi-fi access point with the SSID "WFS210"?
This will appear within a few seconds of turning on the unit.

[Bicurico]

Thanks. No such SSID shows up - tried that, as well...

Bad luck.

What puzzels me is the amount of bad luck I have, when it comes to purchases of such devices. Around 5-10% is always with an issue.

Let's see how the return/replacment works out.

[Bicurico]

Device is already packed and ready to be shipped back.

Amazon handled it in an acceptable manner: They ship a new item, which arrives Nov. 2nd and I just have to bring the DUD to the local post office, without extra costs.

Hopefully, the next device will turn on!

Thanks for your help.

Regards,
Vitor

[medical-nerd]

Hiya

The device came with a USB cable, which is what I am using to charge it. I tried charging it on my laptop, now using a USB charger (1A).

It is charging for 5-10 minutes and I had expected that pressing the power button would do at least SOMETHING like turning on the WIFI LED's, but that is not happening.

Thanks,
Vitor

Hiya

The user manual recommends that the battery be fully charged before use. I had the same experience as yourself, then left it charging for a few hours (about 5) on a usb charger before trying it, then had no problems in turning it on. Using it for anything is another matter...........

Cheers

[Fraser]

Vitor,

There are comments on the Velleman forum that some users who attempted to upgrade the firmware to the latest version ended up with a brick. As the firmware update requires the opening of the units case, I suspect your unit had previously been sold, bricked during a firmware upgrade, and returned to Amazon under some pretext that did not indicate that it was faulty. Either that or the unit accidentally got back into good stock after being returned as faulty.
Amazon are normally pretty good where DOA items are concerned and they pay the return postage or supply a prepaid label etc.

Fraser

[Bicurico]

What got me annoyed was the fact that the device was at least "refurbished" and not new.

If it was new, I would give it the benefit of doubt and keep it for a while and spend time setting it up.

Because that was not the case, it goes straight back. I am tempted to open the air bubble envelope and leave it charging during the day, but that would cost me one air bubble envelope and if the device starts to work, I would still have to send it back now. Better to wait until next week.

I agree with Fraser on this: I have seen many bricks due to faild firmware upgrade attempts and this is exacly how it looks to me. The charging circuit does not involve the CPU/flash, which is why the LED's go on. Otherwise the device is just dead.

The fact that the screws where not fully screwed in and some residue glue on the side of the rubber feet makes me believe it was opened by the last "customer". Also, right now I am still waiting for the PICkit3 to arrive, so I have no easy means of reflashing it, if I wanted to.

I start to wonder if I shouldn't have just asked for a refund...
...but because I am waiting for the PICkit3, it would be a shame to not have a device to test the flashing proceedure. These orders come hand in hand.

Not the end of the world - just have to wait another week and deal with the shipping back proceedure (i.e. verify it arrives and I am not charged for the replacement unit).

Regards,
Vitor

[R_G_B_]

There are so many things wrong with the software and firmware of this thing it's unbelievable and these are still selling at around £100 pounds.

It's only because of Fraser mentioning the problems to velleman did they drop the goods and run like a bunch of crooks!

[Specmaster]

There are so many things wrong with the software and firmware of this thing it's unbelievable and these are still selling at around £100 pounds.

It's only because of Fraser mentioning the problems to velleman did they drop the goods and run like a bunch of crooks!

Im not aware that they have run like a bunch of crooks at all, its my impression that they are co-operating with us in updating the software and discussions about the firmware are happening as well.
What I am aware of is the fact that it took Fraser mentioning the issues to them and with the weight of this forum and its influential membership that got them to acknowledge that there are issues and they are willing to look at this head on to see what can be done about it. So unless you know something that has not been posted in this thread, they are talking to Fraser and another couple of members about resolving the problems.

[R_G_B_]

I was Metaphorical speaking 

It's now been bought to there attention in a reputable forum
That there are problems with the firmware and software and they have now released both of them.

Yes they are as far as I'm aware attending to this problem. But it should not take a forum like EEVBlog to bring their failings to their attention why did they not address these issues and why should it take such effort to bring this to there attention.

Politics of right and wrong no matter what samanitic you use to describe it's just a metorphore in this case but the meaning is what it is ...As if. People can be crooked in all walks of life it's just worded differently. And it seems the better the vocabulary to describe such actions or situation the better you fair at avoiding any come backs
Weasel words can be used to avoid any come back but it is what it is
I may sound harsh but I was telling it how it seems as if ...

[Ian.M]

Its strange that the firmware includes a MPLAB X loadable component: "bootloader.hex", yet they still recommend opening it to flash it with a firmware update.   I wonder whether they haven't got a copy of the PC app for bootloading it correctly configured with their VID and PID (assuming its a USB boothoader), or whether they've got a misconfigured bootloader - e.g. its looking for a button on the wrong I/O pin?    

@Fraiser: Please lean on Velleman for the bootloader source.

The other issue is input capacitance.  I cant find a spec for it anywhere.  The built in test signal has a rise time <1us.  With 1Meg in series right at the input jack, the risetime increased to 41us, from which I calculated the input capacitance as 37pF (41us/2.2*500K), and allowing for stray capacitance that probably means its about 35pF.   If anyone has a capmeter that's got 1pF resolution, it would be helpful if they can make their own input capacitance measurement and post it here.

Anyway the Maplin 60MHz x1/x10 scope probe AQ58N is *INCOMPATIBLE* with the WFS210.  Its x10 compensation range of 10pF to 30pF (nominal) is insufficient for the WFS210, resulting in severe undershoot on x10.  It looks like it needs a probe with a compensation range that goes up to 40pF.   Maplin don't have any other x10 probes so its not surprising they have put the WFS210 on clearance, as I bet everyone who's bought probes with it has returned them!   

[Howardlong]

It could be that the bootloader didn’t work properly or was flakey. It’s such a key component to get right, and you must get it right first time, or else you risk a product recall.

[Mr. Scram]

It could be that the bootloader didn’t work properly or was flakey. It’s such a key component to get right, and you must get it right first time, or else you risk a product recall.

Yes, it has the feel of something that was toyed with, but deemed unfit for release. As you say, a bootloader needs to be bulletproof, or you'd better leave it.

[Ian.M]

So why leave a borked bootloader in the project? Its not like the dsPIC33EP256MU806 requires a bootloader to be present to startup.  There's a CONFIG bit (RSTPRI) that determines whether it starts from the main or the auxiliary FLASH reset vector.   Leaving it in 'smells' like they didn't discover it was NFG till after the product launch.

[Mr. Scram]

I was Metaphorical speaking 

It's now been bought to there attention in a reputable forum
That there are problems with the firmware and software and they have now released both of them.

Yes they are as far as I'm aware attending to this problem. But it should not take a forum like EEVBlog to bring their failings to their attention why did they not address these issues and why should it take such effort to bring this to there attention.

Politics of right and wrong no matter what samanitic you use to describe it's just a metorphore in this case but the meaning is what it is ...As if. People can be crooked in all walks of life it's just worded differently. And it seems the better the vocabulary to describe such actions or situation the better you fair at avoiding any come backs
Weasel words can be used to avoid any come back but it is what it is
I may sound harsh but I was telling it how it seems as if ...

I don't quite understand why you're so consistently harsh. It's obvious that this product has its flaws. However, it would be easy for Velleman to pretend nothing it wrong and to keep quiet. Instead, they opted to help out and to try to improve the issues found. As always, it's not just about the mistakes you make, it's how you deal with them.

Calling them crooks and being consistently harsh only means they don't have anything to gain from trying to help. In that case, it would be better for them to drop the thing and hope it fizzles out quickly. Maybe with a bit of cooperation, a next generation device can be developed that does do what it promises, as this model isn't really that far off.

[Howardlong]

The other issue is input capacitance.  I cant find a spec for it anywhere.  The built in test signal has a rise time <1us.  With 1Meg in series right at the input jack, the risetime increased to 41us, from which I calculated the input capacitance as 37pF (41us/2.2*500K), and allowing for stray capacitance that probably means its about 35pF.   If anyone has a capmeter that's got 1pF resolution, it would be helpful if they can make their own input capacitance measurement and post it here.

Anyway the Maplin 60MHz x1/x10 scope probe AQ58N is *INCOMPATIBLE* with the WFS210.  Its x10 compensation range of 10pF to 30pF (nominal) is insufficient for the WFS210, resulting in severe undershoot on x10.  It looks like it needs a probe with a compensation range that goes up to 40pF.   Maplin don't have any other x10 probes so its not surprising they have put the WFS210 on clearance, as I bet everyone who's bought probes with it has returned them! 

It has two values measured with a Keysight U1733C, up to 50mV/div it's 44/45pF ch1/ch2, then at 100mV/div and above it's 36/38pF. I can compensate at 100mV/div and above with those probes but not at 50mV and below. (I think they're the same Maplin ones, the insert says HP-2060, claimed specs look identical, it's in a drawer full of probes of various provenance collected over some time).

On those two ranges, the capacitance remains constant.

However, even when you have compensated the probe, as you change the vertical (within the 100mV/div and above range), the compensation goes off. I measured the complex input impedance and there's negligible change between the vertical divisions in each of the two vertical bands.

[Ian.M]

Many thanks.

I checked the AQ58N (aka 'HP-2060') probes on my Dynamco D7100 which has 35pF input capacitance and they couldn't be compensated for that either so current stock certainly cant go much above 30pF, if that.   I suspect the supplier has changed the specs, and no one updated the part number.

Your news about the two input capacitance values is *NOT* *GOOD*. It sounds like the input divider design is badly *FUBARED* 

If you (or anyone else) could post two screenshots showing the compensation change with vertical position, that would be helpful.  Confirmation of the above results from anyone else with good enough test equipment would also be useful - lets build up some statistics here.

[exe]

So the WFS210 is not displaying the waveform the correct way around it's time reversed as the ringing should be in the rising edge of the Square wave.

There are many reasons why this may happen. Like, probes not compensated, probe loading, not enough bandwidth to display ringing, etc. People above mentioned bundled probes cannot compensate for input capacitance. This can be the problem. But I doubt it displays waveform "reverse". Although, never seen this scope...

[R_G_B_]

Yes it did display the waveform in reverse I will upload the comparison between both waveforms on the hps140i and wfs210 I'm absolutely certain of that  when I get a chance I will up load the screen shots I took.

[exe]

Yes it did display the waveform in reverse I will upload the comparison between both waveforms on the hps140i and wfs210 I'm absolutely certain of that  when I get a chance I will up load the screen shots I took.

Sorry for my comment if this is the case. But then it looks like very serious (and stupid) bug. Anyone else can confirm this? I'm asking because, who knows, may be it's coincidence that two waveforms look like mirrors of each other while they are not... I'd hook to a signal generator with assymetric waveform.

[Howardlong]

FWIW, although the code compiles, I've yet to get the provided build to work. It builds cleanly (use XC16 v1.24). The generated unified .hex is much smaller than that provided on their website (~197KB vs 954KB), although the .hex provided on the website is largely zeros.

There is some confusion as I believe that some of the LED indications come from the RN171 Wifi module, and not the MCU.

I can restore the .hex files provided and get them to work, but I should mention that I've found I've needed to do a factory reset and a calibration each time I load new firmware.

I don't really have the time to invest in this rabbit hole at the moment I'm afraid :-(

[R_G_B_]

Here's what I found a problem I discovered on the wfs210 as you see the waveform is being displayed the wrong way around.

[Specmaster]

Here's what I found a problem I discovered on the wfs210 as you see the waveform is being displayed the wrong way around.

Is it? Looks to me as if the trigger point has been set at the very tip of the wave and hence why the top of wave is shown before the trailing edge falls away. Move the trigger point lower and you should see the rising edge appearing which is what you have selected.