Monthly Archives: March 2011

LED display modification

A friend of mine obtained a large number of static (non-scrolling) LED signs made by Electronic Displays Inc (EDI).  The signs communicate using RS232 or RS485 serial connections.  We decided to improve the signs by replacing the serial communication with Bluetooth so no data cables need to be routed to the sign.  We also decided to make the signs more interesting by giving them a large message memory and effects such as scrolling, blinking, bold font, etc.

These modifications are easy to add using a board I designed that plugs directly into the socket of the PIC microcontroller already in the sign, replacing it and adding these features.

Our board is on the bottom-left and the PIC microcontroller it replaces is to the right.

Vertical Stabilizer Spars

Started making vertical stabilizer spars.  Got to really use some clecos.  I worked really hard in an attempt to keep everything straight and centered.  Getting parts clecoed together while leaving room to attach more parts was a little bit of a juggling act, but it was enjoyable.

You may notice a maroon scotch-brite pad in the background.  I had been trying to find them locally and finally found them at Fastenal.

Here’s a shot showing more of the clecos.

Tail 3

Made some clips and bent a flange on a piece of channel.  My shipment of Nuvite arrived and I tried it out on the leading edge we made at the workshop.  I was very pleased, but I think I went through the different grades too fast in an attempt to try them all out, so there seem to be some scratches left.

Tail 2

Started working on the tail.  I was hesitant to cut the spar channel on my compound miter saw because I was unsure if it would vibrate too much or get caught and bent.  I held it firmly and cut really slow and it cut perfectly.  I even made the 5 degree cuts on the flanges with the bevel feature of the saw.

Cutting the circle was another matter entirely.  First I used my unibit, but this vibrated like crazy and didn’t seem precise at all.  Plus it seemed to be melting the aluminum more than cutting and the force I was applying to cut was deforming the metal.  Not having a hole saw or a fly cutter I decided to use a forstner bit as a last-ditch attempt.  I added cutting fluid and the forstner bit went through like butter.  Spade bits probably would have worked just as well except mine don’t have a nice tooth on the outside to cut the circle out.

I have been dreading bending the forward spar fitting for a while.  I decided to try using my bench vise and a piece of thick-walled pipe I found in the basement with the correct diameter. I cut a “V” into a block of wood with my bandsaw.  Once I lined everything up, the bending was way easier than expected.

Aluminum Angle Bundle 17

I have tried a few methods to open angle past 90 degrees.  The 4lb hammer method was very tedious for some of the longer pieces so I used the bench vise and WD-40 to squeeze the angle open.  This would have worked much better with a chunk of steel or something to squeeze against, but I could have wasted a bunch of time finding a suitable chunk.  Instead I stacked a bunch of pieces of scrap aluminum together–this was a pain, but now I’m done :-)  On the plus side, it was very easy to control the angle of the squeeze over the entire length of angle.

Aluminum Angle Bundle 16

I’ve made some good progress.  I keep thinking I’m almost done cutting all the aluminum angle, but it keeps on coming.  Here are some of the parts I’ve made since my last post.

Here are all the parts I’ve made so far.