Author: Ed

Raspberry Pi Serial vs. TNC-Pi2 vs. APRX

The APRX iGate program I’m using produces a hardware & software event log file:

2016-09-03 11:24:40.368 TTY /dev/serial0 read timeout. Closing TTY for later re-open.
2016-09-03 11:25:10.373 TTY /dev/serial0 Opened.
2016-09-03 11:32:05.485 CLOSE APRSIS noam.aprs2.net:14580 heartbeat timeout
2016-09-03 11:32:15.495 CLOSE APRSIS noam.aprs2.net:14580 reconnect
2016-09-03 11:32:15.776 CONNECT APRSIS noam.aprs2.net:14580
2016-09-03 12:25:11.154 TTY /dev/serial0 read timeout. Closing TTY for later re-open.
2016-09-03 12:25:46.154 TTY /dev/serial0 Opened.
2016-09-03 15:50:14.905 TTY /dev/serial0 read timeout. Closing TTY for later re-open.
2016-09-03 15:50:46.155 TTY /dev/serial0 Opened.
2016-09-03 16:50:51.155 TTY /dev/serial0 read timeout. Closing TTY for later re-open.
2016-09-03 16:51:26.155 TTY /dev/serial0 Opened.

I have no idea what’s going on with the “read timeout” messages. They seem to occur almost exactly a hour apart, except when they’re a few hours apart. The TNC-Pi2 board includes a PIC processor; maybe it loses track of something every now & again, but APRX only notices if it happens in the middle of a read operation.

The APRSIS server connection drops every few days and APRX seems well-equipped to tolerate that.

All in all, it’s working fine…

2016-09-21

Vacuum Tube LEDs: Fully Dressed 21HB5A

Black PETG definitely looks better than cyan for this job:

21HB5A – Black PETG base – flash

Holding the plate cap to the tube with a thin ring of opaque epoxy cuts down on the glare under its edge:

21HB5A – Black PETG base – cyan phase

Fire in the bottle!

21HB5A – Black PETG fittings – punched drive platter – purple phase

It’s still running basically the same Arduino code as before, but I have some ideas about that…

2016-09-20
Hard Drive Platter Punch Bushing

The last time I punched a hard drive platter, I lathe-turned a bushing to center the Greenlee punch:

Greenlee punched drive platter

This will work better:

Vacuum Tube Lights – Greenlee punch bushing

The OD centers the bushing inside the punch body, the ID captures the screw, and the raised boss captures the platter.

After drilling the platter on the new fixture, it’s ready for punching:

Hard drive platter – Greenlee punch bushing

Line everything up, turn the screw, and It Just Works:

Hard drive platter – punched

The masking tape holds the platter to the bushing, eliminating the need for a third hand. The bushing emerges unscathed, ready for another platter. Overall, I think that’s faster and less messy than milling the platter ID on the Sherline.

Printing out a base to fit the Duodecar socket and assembling all the parts:

21HB5A in socket on platter – detail

The Duodecar pin circle (19.1 BCD + 1.05 pin diameter) will actually fit inside a hard drive platter’s 25 mm unpunched ID. It might look a bit squinched, but the less you see of the socket, the better. I’ll try that on the next one.

The OpenSCAD source code is the same as before; set Layout = Bushings; and a bushing will pop out.

The original bushing doodle with dimensions:

Greenlee 1.25 inch punch bushing for hard drive platter – dimension doodle

2016-09-19
Poughkeepsie Waterfront at Night

Another Walkway Over the Hudson Moonwalk provided a good view of the Poughkeepsie waterfront:

City of Poughkeepsie Waterfront – night view

The railroad station’s parking garage produces the big mass of sodium light in the middle and (I think) the bleached church on the far left has mercury vapor floodlights.

The smaller spots of cold-white LED lighting scattered here-and-there will gradually expand and, in five years or so, take over the entire vista …

2016-09-18
A Curiosity of Sparrows

There’s obviously something going on inside the long-abandoned nesting box:

Sparrow investigating bird box

You’ve seen this happen to people, too:

More sparrows on the bird box

How many sparrows can fit on the roof of a bird box?

Four sparrows investigating bird box

There’s always room for one more:

Late season sparrows on bird box

Perhaps they were having a family reunion?

Taken with the Canon SX230-HS from the patio, zoomed all the way, and ruthlessly cropped.

2016-09-17
Vacuum Tube LEDs: Aligning the Plate Cap Leads

The original plate cap, even without fins, seemed entirely too large for the 21HB5A tube. There’s not much wasted space inside and, after trimming the outside a bit, this is about as small as seems possible:

Vacuum Tube Lights – thin cap solid model – section

PETG doesn’t bridge well and, after cleaning out the wire hole, the remaining shell didn’t hold the brass tube very securely. Epoxying tubes into two caps at once, with a longer brass tube holding them in alignment, worked well:

Black PETG Plate Caps – brass tube alignment

The tube eliminates vertical tilt and you (well, I) can eyeballometrically align the caps and tubes in azimuth. The thin ring of JB Kwik epoxy around the brass tube isn’t visible, so it’s all good:

21HB5A – Black PETG base – flash

This project may eventually force me to try epoxy coating, high-build primer, and good paint…

2016-09-16
Monthly Image: New Coopers Hawks

“Our” Cooper’s Hawks have long since flown off, although one occasionally swoops through the yard on an urgent mission. I took this picture on an early July morning, when they were still being companionable:

New Coopers Hawks – Watching the Area

Taken with the DSC-H5 and 1.7x teleadapter, zoomed in all the way, and dot-for-dot cropped. The birds look fine and the image looks awful…

2016-09-15