Teardown: Generic Super-Cheap 640×480 Webcam

Recently, while sorting through a box of old, underused, assorted electronic “junk”, I came across several old cheap webcams that I bought in a pinch off eBay back in 2011. These units were especially cheap – they were had for about US$2 and are still available online even today.

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I remember that these were a fairly popular model, and they were sold under various guises. Some of them included uprating the resolution to 3MP, 5MP, 10MP or even up to an incredible 30MP (driver-based trickery). This one was advertised honestly and sold cheaply, but the plastic bezel already begins to exude “lies” – 10x digital zoom? Eugh. “Megapixel”? Yeah, 0.3 of them. Regardless of what you bought, it was all interpolated lies – this was a cheap plastic-bodied, plastic-lens, fixed focus, VGA webcam. As long as you realized that, you were fine.

20150304-2001-3845Unlike the more modern 20150304-2001-3846webcams, the video went through USB 2.0 but the audio was only available as an analog 3.5mm plug to go to the microphone port of a sound card. The cable, as expected, was slightly short. The unit featured white LEDs which can be controlled by the dial on the cable.

 

The unit has the ability to stand on its own, weighed down by a single nut in addition to the plastic shell, and also swivel up-down and left-right. The stand itself splits for clipping onto a monitor. There is a button at the top to launch an action (e.g. take photo) but this isn’t very much used. No indicator LED is provided.

Of course, such a unit is not very useful today, given the poor image quality, and most cameras have advanced far from where this was. As a result, I decided to take one apart to see what was inside …

Teardown

The unit comes apart easily with undoing the two rear screws. Inside we find a lot of hot glue, and relatively cheap construction. As expected.

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I particularly like how the electret microphone capsule is just “slotted in” somewhere in the casing, and a PCB mount push-button is “repurposed” as a chassis mount button with two flying leads soldered on to two pins. Getting rid of some of the wires, we can get to the PCB and get a closer look.

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The unit utilizes an EtronTech eSP268A6 camera bridge chip, and another unknown IC – possibly an op-amp for driving the LEDs or an EEPROM, where the yellow and blue cables are from the potentiometer. Interestingly, the chip does have a provision to provide USB audio as well but they just didn’t utilize it. Maybe it’s because there needs to be an additional payment to use the block? It’s a bit sad. The chip supports up to 1.3MP sensors in 8-bit mode, but offers no MJPEG support internally.

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The front side shows the lens assembly, which is a plastic lens in a threaded tube, which you can rotate to adjust the distance (and hence focus). The LEDs are not supported in any serious way and just protrude from the board. The 12Mhz clock crystal is mounted on this side as well. An unusual feature is that the PCB is green on this side, and black on the other – you don’t see this very often, and you’d expect the opposite for optimizing stray light into the sensor. Removing two screws frees the lens frame from the PCB, and clipping off all the LEDs lets us get closer to the sensor.

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Lets get a little closer still, with the macro lens.

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The fact you can get this for about $2 is still rather astounding, even if it’s a very poor webcam. Some electronics shops might charge the same for six white 5mm white LEDs or an electret mic capsule.

What’s it good for?

The sensor itself is only 640×480 VGA, and the processor isn’t particularly special, so you don’t get any fancy compressed modes – just YUY2. You don’t get a “fixed” frame-rate, as it falls with longer shutter times in low-light – a characteristic common to most webcams.

formats

The dynamic range is pretty poor as well, resulting in blown out highlights and noisy images. The plastic lens doesn’t help either, with colour fringing and a very smeared look even with manual focusing.

Not-Great

But with a little experimentation by twisting the lens collar, it is possible to manually focus this unit to see very small details – like a macro camera. There is a large amount of distortion, but the microprint on an AU$100 note was resolvable quite easily.

Macro-Camera

It seems that the closest practical focus gives about 17 pixels per 1/64th of an inch based on my old metal ruler.

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Other than that, there really isn’t anything to commend this camera for – maybe it’s better than nothing, but it’s not going to give a good picture regardless, purely because of the lousy optics, lousy sensor and processing hardware.

About lui_gough

I’m a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!

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