Tuesday, October 26, 2010

Camera Update

After several months of patient waiting i now have a set of microscope objectives (4x, 10x, 40x and 100x oil) and an m42 to rms ring (i wanted it for a mounting platform rather than for my current camera)


So far i have significantly higher magnification than was ever possible with my Helios 44-2

Taken with 4x lens

Taken with 10x lens

I am having trouble with the 40x and 100x objectives though, i am quite sure that the focusing strength of the lenses are high enough that i need to position the sensor even further back. I made this assumption when i looked at the camera configurations for trinocular microscopes. So far im getting some awesome results, going even further i purchased a slide micrometer to determine the scale.

Helios 44-2
4x Objective
10x Objective

 With a bit of rough calculations it works out to 3.5 px \ 0.01mm for the Helios, 10.7 px \ 0.01mm for the 4x and 26.5 px \ 0.01mm for the 10x objective... i really want to get the 40x and 100x objectives working now.

Wednesday, October 20, 2010

Huge Eprom Eraser

Over the past year i joined a small hackerspace that was just getting on its feet, one of the major initiatives we have going on is recycling... or what recycling really should be. In that time i have collected over a hundred eproms and i really should do something with them. I already have a chip programmer but lack the necessary eraser needed to prepare the chips for programming.

Naturally i went online to see what was out there... for 5 to 20 dollars i could get an eraser with a capacity of 2 or 3 chips. That won't do the trick if i want to batch test a few hundred of these things. The solution came when i found an old florescent blacklight in the corner, it drives f15t8 bulbs and i can easily get g15t8 bulbs which emit light in the crucial UVC spectrum.

The only real issue is the fact the UVC spectrum is very dangerous, enough to cause burns to the skin and your retina! I chose to use a cheap metal toolbox as an enclosure and sealed every seam to prevent light from escaping.

The rest was just dismantling the old light for the parts i needed and bolt them to the inside of the toolbox.

I used an old spring wound timer to control the time of exposure and added a safety switch to cut power if the door was open.

 Also i added a tiny plastic window so i could see if the bulb was working, UVC light won't pass though, pretty much the only thing it will pass though is quartz. Everything works fine so far, it takes about 7 minutes to erase a 27c512 eprom. I will run more detailed tests when i have the free time.