USB microscope

[millegps]

I'd like to start a thread about cheap USB microscopes (under 50$), intended to be use for pcb check.

In particular, if you own one, I'd like your opinion about resolution, frame rate and (real) magnification.

If you can, post also some capture samples.

Thank you!

[cyber_drifter]

I bought one to help with SMD work, but the microscope is that close to the board that there's no room to work. They are good for checking for dry joints and breaks in the track though. I bought one of the dirt cheap ones so maybe that's why it's not so useful?

[millegps]

One of my doubts was about focusing and distance between PCB (or what you need to inspect), because with hot air I guess it's very easy to melt down plastic protection or even lens

[pickit2]

see http://www.romanblack.com/VGA_microscope/VGAmic.htm

[millegps]

reading now, sounds very interesting!

Posted on: July 23, 2013, 11:56:05 23:56 - Automerged
Very nice project, but I think for 0402 (which is what I'm interested for) 9x magnification is not enough.

I saw also some optics, maybe if you change with the right one you can get better magnification.
Sometimes I used an optical professional microscope to check 0402 SMD components and I saw that a good magnification is between 20x and 30x

[solutions]

Why USB? What are you trying to do with the computer? If it's just viewing, or human inspection, it seems like too much technology and expense for the job.

If you are looking at automated joint inspection, and you are using 0402 (the only reason to do that is lots of them, high density placement), which I am guessing you are doing, you need to think about sharing what you have for software and what you've done with it, how you are assembling these components, not just starting and posting silly topics on here. Merely throwing an image on a screen to just do visual inspection or repairs is completely silly.

That said, the Intel USB microscopes were cool, and cheap, but there's no 64 bit driver for them (thanks a lot, Microsoft idiots).

So, what do you use for the inspection setup? How are you assembling these?

[Gallymimu]

I've bought several USB microscopes on ebay for electronics use.  They all work fine BUT they tend to lie about the resolution that the cameras are capable of so be careful.  They will sell them as X megapixels and they will really be just 640x480 cameras.

I've found them to be pretty good for electronics inspection and assembly but I honestly get more mileage out of a good 8" magnifier lamp.

[Ichan]

I like the that VGA_microscope idea for inspection, it can be even cheaper by using a cheap lcd TV so no vga converter needed. I may build this one soon, again for inspection - for hand working with smd components i agree that a good large magnifier lamp is the best.

-ichan

[calabazas]

I've tried a couple of USB cameras myself. Those can show picture and lighten things up but not precision. Has anyone seen a high quality high-resolution one in the market?

Low-end camera is priced at around $30. I wouldn't mind to spend $100.

[pickit2]

you need to get away from the cheap usb & microscope type of camera

http://www.linkhamson.co.uk/_blog/Electronics_Inspection/post/why-use-a-pcb-inspection-camera/

[Gallymimu]

you need to get away from the cheap usb & microscope type of camera

http://www.linkhamson.co.uk/_blog/Electronics_Inspection/post/why-use-a-pcb-inspection-camera/

what's the cost on those?  The old mantis microscopes we used were several $k used.  Pretty far off from a $30 or $100 webcam on a stick.

[solutions]

What you pay for is working depth and the quality optics, and number of elements. needed to pull that requirement off.

See how long your plastic lenses last when you are soldering 1 cm below them..

[millegps]

Well I do not agree with you.
As I said I'm looking for a cheap USB microscope, so it's not that expensive.
About too much technology, well since we are all writing in this forum, we all have a computer, with many USB ports you can use.
So to me it seems the easyest and cheapest way to do an inspection.

One more thing: if I'm working with 0402 I'm not at alla scared by technology to plug an usb webcam on my pc...

About my project: I'll have my pcb next week from eurocircuit. I'm using 0402 since space is very critical for my application.
I already used 0402 with cc1100 radio. I'll assemble prototypes with hot air gun, then it will go in production (as I did for other projects).

I'll use microscope to visual check connection, since I don't have an optical microscope.

Last thing: I don't think it's a silly topic, there's also a moderator here who can delete this topic if he thinks so.

I'll reply other posts later

Why USB? What are you trying to do with the computer? If it's just viewing, or human inspection, it seems like too much technology and expense for the job.

If you are looking at automated joint inspection, and you are using 0402 (the only reason to do that is lots of them, high density placement), which I am guessing you are doing, you need to think about sharing what you have for software and what you've done with it, how you are assembling these components, not just starting and posting silly topics on here. Merely throwing an image on a screen to just do visual inspection or repairs is completely silly.

That said, the Intel USB microscopes were cool, and cheap, but there's no 64 bit driver for them (thanks a lot, Microsoft idiots).

So, what do you use for the inspection setup? How are you assembling these?

[bbarney]

Last thing: I don't think it's a silly topic, there's also a moderator here who can delete this topic if he thinks so.

Or he could delete some members if they don't play nice 

[millegps]

I will try next week an USB microscope, sell as entry level professional tool, real resolution 1280×1024, I'll report my test and if allowed also brand. You can find on ebay for about 205€ (270$)

I've tried a couple of USB cameras myself. Those can show picture and lighten things up but not precision. Has anyone seen a high quality high-resolution one in the market?

Low-end camera is priced at around $30. I wouldn't mind to spend $100.

Posted on: July 25, 2013, 08:41:55 20:41 - Automerged
Nice comparison between optical vs digital.
I agree with the article, that using stereo microscope for a long period is not comfortable.

you need to get away from the cheap usb & microscope type of camera

http://www.linkhamson.co.uk/_blog/Electronics_Inspection/post/why-use-a-pcb-inspection-camera/

Posted on: July 25, 2013, 08:49:04 20:49 - Automerged
I don't know the price, but for sure a *real* full hd camera will cost more than 100$.

As I said on the previous post, cost for an entry level tool is 270$ (brand dinolite)

what's the cost on those?  The old mantis microscopes we used were several $k used.  Pretty far off from a $30 or $100 webcam on a stick.

Posted on: July 25, 2013, 08:52:31 20:52 - Automerged
main concern, on my 2nd post, was just that

What you pay for is working depth and the quality optics, and number of elements. needed to pull that requirement off.

See how long your plastic lenses last when you are soldering 1 cm below them..

[calabazas]

$200 to $300 price range is also fine, as long as it can do the job. It can be a handy tool to have during travel. Compact, precision, with adjustable light, with compact stand, USB, and hopefully a nice piece of software.

For traveling engineer need to see 0201.

[millegps]

Sorry, I don't want to be controversial.

Sense of the first post was to share experience from users who already had a microscope.
If people can share something different is very welcomed. I'm pretty sure with the right optical components you can even do your own home built microscope.

Or he could delete some members if they don't play nice  

Posted on: July 25, 2013, 09:10:26 21:10 - Automerged
I guess it's just for checking, or are you able to do hand rework on 0201?

$200 to $300 price range is also fine, as long as it can do the job. It can be a handy tool to have during travel. Compact, precision, with adjustable light, with compact stand, USB, and hopefully a nice piece of software.

For traveling engineer need to see 0201.

[pickit2]

well your blinded by the thought of you must use usb, have you even looked at lens from the point of focal length, field of view, and all the other working of camera and lens.
a good analog camera and the right lens, will be cheaper than a usb microscope.

A few years back, I bought a colour camera, telephoto lens motor control zoom, I was testing it at 12" up to about 1 mile, cost £25 and was using it with a input card to my pc.

As been said cheap usualy means you can zoom 50-500 but that is no good for the result you want, reason only a small part of what your looking at will be in focus.

I would even say a digital camera with micro function, would beat the e-bay microscopes.

[calabazas]

Posted on: July 25, 2013, 09:10:26 21:10 - Automerged
I guess it's just for checking, or are you able to do hand rework on 0201?

Portable camera is for inspection and taking picture.
If need soldering, better use stationed microscope.


Posted on: July 26, 2013, 06:07:42 06:07 - Automerged

I would even say a digital camera with micro function, would beat the e-bay microscopes.

Digital camera is bulky to carry. Micro mode can show minute item. Can it lighten things up in small area continuously with adjustable lumin? Will it show real-time picture on big screen? Adding all these up, camera becomes expensive and unsuitable.

[solutions]

Inspect all you want, if you find a fault, then what?

As I said, you want to locate a fault, hold the location, get the soldering iron out, and make the repair.

A toy microscope has zero working depth and sucks for doing that repair. On top of that, your toy microscope is NOT binocular meaning your eyes have zero sense of depth so repairs are not very precise.

And show me a USB microscope for less than a bazillion dollars that has a 6-7 inch (150mm) working depth while maintaining a 10-40x magnification (optical zoom, not lens changes) and I'll shut up.  There's a reason why these microscopes cost over a grand...the optics and the stability (mass) of the platform.

Yes I have a computer. But it's not a monitor...it just has one. You can buy an Extech on ebay for a couple of hundred bucks, but it's a toy. You can't do rework with it. You point to a crappy joint, snap a picture, then what?

I'm somewhat fascinated by how you are putting down 0402's using hot air - glue first? Solder melting point? A good way to destroy or damage components due to lack of temperature control (not to mention cold solder joints). And if you are producing a bunch of these, why aren't you running your pilots through the chosen assembly house - there's a lot of debug just in that part of the cycle? Not telling you what to do, but want to learn how you are getting away with these practices.

[millegps]

yes, I focused only to usb since they are cheap and ready to use, so I was trying to find out how reliable they are.

BTW I found also that there are some stereoscopic optical microscope under 200€ (~260$), but I don't know about quality

well your blinded by the thought of you must use usb, have you even looked at lens from the point of focal length, field of view, and all the other working of camera and lens.
a good analog camera and the right lens, will be cheaper than a usb microscope.

A few years back, I bought a colour camera, telephoto lens motor control zoom, I was testing it at 12" up to about 1 mile, cost £25 and was using it with a input card to my pc.

As been said cheap usualy means you can zoom 50-500 but that is no good for the result you want, reason only a small part of what your looking at will be in focus.

I would even say a digital camera with micro function, would beat the e-bay microscopes.

Posted on: July 26, 2013, 08:19:14 20:19 - Automerged
With SMD I don't use iron, but hot air.

If you find the fault you remove component, cleanup pads and then place component again.

BTW, I think there's a misunderstanding between us.
I never said I want to buy a 20$ USB microscope to replace an 1k optical stereoscopic microscope.
You can say the same for an oscilloscope, an SA, a rework station, and in general anything you can buy.

There are professional tools and there are tools for hobbysts, but I'm not here to compare a professional tool (optical microscope) with a toy (USB microscope)

I said, what can you do with a 20$ microscope?

I don't even want to take some picture of a joint (never said that), but just to inspect joints, find bad joints and fix them.

About 0402, to put them down I use my hands, tweezers and solder paste and stencil (optional). No glue. When you buy solder paste you have also a datasheet of the paste, where you can find melting point temperature. Usually you can find solder paste with melting point at ~180°C or ~220°C. You can find also many video on youtube if you are interested, i think a video is better than 1M words. You can start with searching "smd stencil reflow" on youtube and watch the first video to have an idea of the process.
And no, you will not destroy anything unless you don't stay for many seconds with hot air on the same component. For sure it's not the best way to respect an heating profile, but it isn't production it is only prototyping.

If you search for "qfn64 hand soldering", this how to NOT use hot air...

Even if you have someone which can assemble PCB for you, they will not setup a pick and place machine to produce only a couple of prototypes, unless you want to throw away your money.
Remember also that if you have to match an RF network for example, you need to change by yourself some components and it is unreasonable, in terms of time and costs, to have someone that do that for you.
BTW, if you know someone who can do that for a reasonable price let me know

Inspect all you want, if you find a fault, then what?

As I said, you want to locate a fault, hold the location, get the soldering iron out, and make the repair.

A toy microscope has zero working depth and sucks for doing that repair. On top of that, your toy microscope is NOT binocular meaning your eyes have zero sense of depth so repairs are not very precise.

And show me a USB microscope for less than a bazillion dollars that has a 6-7 inch (150mm) working depth while maintaining a 10-40x magnification (optical zoom, not lens changes) and I'll shut up.  There's a reason why these microscopes cost over a grand...the optics and the stability (mass) of the platform.

Yes I have a computer. But it's not a monitor...it just has one. You can buy an Extech on ebay for a couple of hundred bucks, but it's a toy. You can't do rework with it. You point to a crappy joint, snap a picture, then what?

I'm somewhat fascinated by how you are putting down 0402's using hot air - glue first? Solder melting point? A good way to destroy or damage components due to lack of temperature control (not to mention cold solder joints). And if you are producing a bunch of these, why aren't you running your pilots through the chosen assembly house - there's a lot of debug just in that part of the cycle? Not telling you what to do, but want to learn how you are getting away with these practices.

[PeterMcMonty]

I never worked on 0402 but usually I work on 0603. At work I have a very good binocular optical microscope with a 6x lens and LED lightning: it's for me an unvaluable and essential tool, togheter with an NBC reworking station, with iron solder, desolder and hot air.

Hot air is unvaluable when I need to remove multi pins components, even 64 LQFP !!! It needs a very good skills and a firm hand to do such a job without burn the chip and the PCB all around

To solder a 64 LQFP I prefer a very clean iron tip and some little solder to wet all pads.

At home I owe a toy USB microscope that I bought for few € at an electronic fair: very nice toy, but a toy. After few days I put it in a drawer and I forgot it.

I saw some tools that give you a good image on a computer screen, but I think they are used for inspection only... I don't figure myself watching a video on my side (or even on my front) and coordinate my hands to work on the circuit. I think it needs some practice: look in one direction that is not where you have to work, but I suppose it's feasible with some exercise.

[eSilviu]

Basically, all cheap USB microscopes are just cheap USB webcams, with the lens moved away from the CMOS sensor.
You can convert a USB webcam to a "microscope" just by adjusting the lens position beyond the limits allowed by the webcam manufacturer. It will work, but you will not have the adjust-ability offered by a "usb microscope". For a fixed focal point it may be enough...

[millegps]

I bought one USB microscope. I can confirm it is really invaluable (with all the limits already mentioned) tocheck SMD joints.
I paid 25€ on a store. Resolution is 1024x768 and it claims to do a 220x magnification.

Here's some captures



the same pins with a greater magnification


you can see also dust

[Ichan]

At what magnification all those pictures taken? What is the distance from the board to the microscope? What is the light source used?

-ichan