by techpawpanda

So you need to solder something small, but it is so tiny you can't see it properly. This is often the case with surface mount components (SMD), and we will show you an easy way to handle it.

Before deciding on which solution to use, you should determine what your requirements are.

For us, it was key to have a responsive system, a comfortable working position when soldering, a light, portable solution (at least that we can stack away easily), and of course, enough magnification to see very small components. The list became rather extensive but it is important to list all your ‘wants’ upfront and then peel away the unobtainable ones later.

In the end, our requirement list looked like this:

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• high magnification level
• responsive, i.e. high frame rate, if a camera
• long distance focus so there is enough room for tools and soldering irons under the magnifier
• light and small equipment
• built-in or easily added light/illumination
• possibility to make a recording/video (to create instructional videos)
• affordable, since we're on a tight budget (max $100)

We searched the web for different solutions, but most fell on a single parameter: price. There are many nice bench-top microscopes built for soldering, but none that fit our budget — normally by a factor of 15x in price!

We looked at using video cameras with close-up lenses, popular with some bloggers. It may’ve worked fine, but we didn’t want to risk our only video camera getting splashed with 250 degree Celsius melted solder.

Another option was to use a web camera. We tested the idea with an old camera, and found the magnification and focus distance weren’t a practical setup.

We also looked at so-called, USB microscopes. They are essentially a web camera with a different lens. There are, of course, a whole flood of on the market so how do we choose one? In our case, we started with a list of requirements, so we assumed it would be fairly easy.

Well, it wasn't so easy, mainly due to poor documentation. Many product sheets and specifications don't contain even the most basic optical performance information. How can one possibly decide on which product to buy? To choose, we simply excluded the ones without useful or enough information.

We settled on a USB microscope camera with 1.3 megapixel resolution, adjustable focus from 10mm to infinity (as stated), and up to 200x magnification. The resolution was chosen since many devices don't support fast data transfer over the USB channel, and 1.3 megapixel is as low as we wanted to go on resolution (lower resolution means less data in each image frame to transfer to a computer). Since the frame rate isn't always constant and limited by the exposure time (depending on the camera’s sensitivity), we opted to add 2 USB powered .

The image shows our kit: the USB microscope, two LED lamps, a USB hub (most low-cost 4-port work fine), and a to blow away solder smoke.