BlackBerry^® crushing apparatus

The procedure for this involves winching a 12 kg weight 8 meters up into a tree, then releasing it (using an electromagnet) onto a BlackBerry device. My brother took a few photos while I was setting it up. I especially like the two photos above right - they give a good sense of scale. The really long stick I'm holding in the left of these photos is not quite long enough to reach the branch I'm hooking on to - I had to go up on a stepladder and hold the end of the piece of wood above my head to reach the branch. Eight meters is a long way up!

I used an electromagnet, made from an small transformer, to hold the steel weight. When the electromagnet is de-energized, the weight starts falling, exactly straight and vertical. Getting the aim just right is a bit tricky - at left, I have the weight suspended just 20 cm above the unit under test. Leaving it dangling for a minute helps to establish exactly how the tree flexes, and allows the unit to be positioned directly under. I also put some pieces of plywood around the drop zone, and some plastic on the grass. After previous such events, I had electronic components scattered all over my lawn.

A target set up. The unit is balanced on a piece of angle iron in an attempt to split it in two.

Here's cranking the weight up, using a small winch setup I specifically made for this purpose. Cranking that 12 kg weight up 8 meters in one go repeatedly, is a bit tiring on the arms! Fortunately I had volunteers to help.

Once the weight was cranked up, I usually backed it off a little bit to make sure the magnet was not pushing against the pulley (that would mess up the aim), and then waited until everything settled again. Sometimes a light wind would also cause the tree to sway, so getting the perfect release conditions was, at times, a waiting game.

The spiraled phone cord you see in this picture is the wire supplying power to the electromagnet. The weight is released by cutting power to the magnet.

Sadly, the "split in two" experiment wasn't that successful. Some motion in the tree threw the weight off target and off angle, and we neglected to take a photo of the result.

The angle iron was somewhat flattened from the impact, so we couldn't repeat that test again.

But below are some photos of other results for your enjoyment...

The flatter the object to be crushed already was, the more severely it was crushed further, with bare circuit boards yielding more flattened results than whole units.

A stack of coins is particularly interesting to crush. Something has to yield on impact...

...and with the coins being the softest part of the system, it's the coins that end up taking up the damage.

Immediately after a drop, the coins were too hot to handle. But they were about 10% bigger than before, and with the picture from each coin imprinted onto the adjoining coins.

The coins actually ended up scattered after impact, but here's piecing the fit back together. You can see the top edge curled up. The weight wasn't completely on target, and the curling up is where the edge of the weight was.

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