Results of today's printer work

A very confused evening with a good outcome.
I decided to poke around a bit, and fired up the machine. I immediately hit problems because I could not get sensible readings from the thermistors, both the hotend and the print bed read all over the board, from 0 to 38 degrees (actual room temp is about 22). I spent a full 2 hours on this, eventually completely disconnecting everything from the RAMPS board, removing it from the CPU board, wiring a pot to the thermistor input, doing a careful inspection of the board, etc. The thermistor is as simple as circuits get, a 2-resistor voltage divider with a 10uF filter cap going into an A/D channel on the Arduino. Everything was fine yet there was some source of noise in the system.

Long story short, after 2 hours of dinking around and chatting with one of the designers of the board on the IRC channel, I suddenly realized that I'd moved the board to the USB hub instead of the PC, and that hub is a hunk of junk. The board runs from USB power. I moved it to the PC and the problem went away.

feh.

Anyway, in the mean time I also hooked up my new power supplies though they are not yet in an enclosure. They work fantastically. I'm going to build a box for them later, and I think I will be printing an enclosure for the electronics after my new heat sinks arrive, then I'll have to do some rewiring because I made some of the wires way too short.

I was thinking I'd try to print something on the broken glass, it's held together by tape on top, but it's bent in the middle by about 0.75mm and that's too much for a good print.

Neat stuff

There were several new Arduino platforms announced at the Open Hardware Summit yesterday.
Of course they're going 1.0, that was the expected news. But they also are releasing the Arduino Leonardo - it has a target price of $20, and uses an AVR chip with USB built in so the parts count is very low and you can prototype USB connected devices which then can be produced in quantity with only the one chip.

They also announced the Arduino Due which had a bunch of stuff on it including Wifi; it has an ethernet + wifi shield built on board.

They're holding up the official 1.0 platform release to provide solid support for these two new platforms. But once they release 1.0 they say they're going to try to avoid breaking stuff for a while :)

Man, I hope I have time to do an Arduino demo next year besides doing a 3D printing one and running the blinkie room.

Today's progress

I built an enclosure for the two power supplies from the sheet metal from an old computer that I threw onto the junk pile years ago. Pretty much complete, I just need an XLR panel connector for the output; that's the standard for the high current power for the RepRap printer.
The switch came from an All Electronics grab bag about 5 years ago, and the power connector from a dead PC power supply. The fan hole is too small but that's the biggest chassis punch I have right now.

Software problem solved

The latest release of the RepRap software that I'm using was causing me significant issue, but it turned out to be just a text file sitting there that specified gcode to be prepended to the output. It caused my printer to do weird stuff on startup. I goofed around with this for probably 2 hours over the last 4 days.