Thursday, August 25, 2011
Getting started with the Altera DE1 FPGA board: Create and download a simple counter
Monday, August 22, 2011
CNC milling glass plates and mirrors
Clamping the glass plate to the table is the critical part of the process, and so I built a jig that allows the glass to be held laterally with shims, but does not require a high clamping force, which would crack the glass.
Cutting parameters:
.085" dia diamond burr
3000 RPM
1-3 inches per minute feed
Cut depth .130" (full material thickness)
Flood coolant with soluble oil cutting fluid
Older post: http://benkrasnow.blogspot.com/2008/08/cnc-milling-glass-plates-and-mirrors.html
Saturday, August 20, 2011
Effect of acetone vapor on thermal printer paper
I am not sure of the chemistry involved, but I have found that acetone and isopropanol vapor will darken the ink in thermal printer paper. There is also a strange reversible blanking effect, where continued vapor application will cause the dye to temporarily become colorless. Do you know the chemistry involved?
Wednesday, August 17, 2011
Saturday, August 13, 2011
Water vortex display from SJ City Hall exhibition -- repair and upgrade
I built this project a few years ago with a friend to help get him interested in mechanical design. Later, the project was adapted for display at a "tech and art" exhibition at San Jose City Hall. After 8 months, the painted steel impeller began to rust and discolor the water in the tube. I took the device back to my shop and replaced the original aluminum shaft with a stainless steel shaft, replaced the shaft seal, and changed the impeller to an all-plastic design. If I were designing the device again, I would opt for a spring-loaded PTFE (Teflon) shaft seal, which I have used with great success in other applications.
Drill motor control:
http://www.youtube.com/watch?v=7yEABsNyRfo
Original video showing the WiFi-controlled watering can and vortex tube:
http://www.youtube.com/watch?v=XKrlRJ-GJms
Thursday, August 11, 2011
Repairing the 5V output from a Mastech HY3005D-3 (cheap import) power supply
Sunday, August 7, 2011
Transcranial Magnetic Stimulation project - part 2
I achieved neuronal stimulation of my primary motor cortex by using a single 15-turn coil and 1700 volt charge on the capacitor bank of about 190uF. The exact position of the coil on my scalp makes a very big difference in how much stimulation is achieved in the motor cortex. I would have suspected the single coil would produce much more diffuse stimulation and positioning would not be so critical. I never got any decent neuronal stimulation with the butterfly coil.
Wednesday, August 3, 2011
Cooking with thermite
I ignited four pounds of thermite made with aluminum / iron (III) oxide in a flower pot. The thermite reaction quickly formed liquid iron which dripped down out of the pot, and into a ceramic pan. I put a beef kebab directly onto the liquid iron, which cooked the food in under a minute. It was delicious!