Tuesday, March 13, 2012

Alarm clock project 3: installing buttons, final look

First post: initial opening and beginning research
Second post: cutting
This is the third post.

This post is how I cut holes for and installed the buttons. There are pictures at the bottom for how the alarm clock turned out.

I used this hole-saw drill bit, which was 1'', and I needed something a little bigger than 1 1/8". 1 1/4" would be too big.

Clamping the lid. I put a wooden spacer underneath that was flush to the lid. This way the underside of the cut would be cleaner.

Pictures after drilling.

Here you can barely see the pencil outline of the desired hole. I have to sand away that much.

Poor man's sander. After sanding by hand a bit, the sandpaper taped around the hole saw would fit. This method worked pretty well. First I sanded it by hand, then spun it with a drill. I was careful not to let the hole saw slip or cut me while I held the lid.

 Sanded holes.

Test fit, it worked well.

Test fit.

Mounting the button circuit board.

These mounting posts originally held the CD player circuit board too, so I had to substitute these extra silver washers to make the screw tighten.

Here's how I soldered the buttons. I just connected them to the leads of the existing buttons so that they would still operate.

I left enough slack in the wires so that one could open the lid and see inside and so that they could bend easily to a good closed position.

Here's soldering the wires from the backup battery (for when the power goes out). This is the first time I used heat shrink tubing; I heated it with a lighter, which worked well enough.

As you can see from the above picture, I forgot to put the wire through the hole in the circuit board before soldering back together. So I had to cut it, put it through the hole, and solder it again (it wouldn't fit around). :P

 Closed lid.

How the wires reach under.

Finished alarm clock.

What's visible when you open the lid.

Hope you thought that was interesting!

Alarm clock project 2: cutting

First post: initial opening and beginning research
This is the second post.
Third post: installing buttons, final look

So I completely finished this project a little over a month or so. It's taken a crazy long time for me to post on it since I first started (Nov '11). Sorry about that for anybody who reads this and notices the discontinuity. I'll finish it up today.

I wanted to install bigger snooze and alarm off buttons on my alarm clock for ease of use. Read the first post for more information.
This post is about how I cut the unnecessary plastic away with a hacksaw. (cutting the holes for the buttons comes next.

First I figured out where the holes should go so that I know what is in the way. With the data sheet and a caliper I figured out the correct size of the hole. These buttons have clever clasps/latches/"wings" that push out on the hole to keep the button in place. These flex like a spring and adapt to a range of hole sizes, so I didn't need to be super precise. I drew the hole size on some graph paper with a compass so I could check the placement and draw around it on the alarm clock. The hole in the middle of the paper is for lining it up with the center lines I drew on the alarm clock (using the lines in the graph paper).

I'm using the darker circles closer to the center, as opposed to the lighter ones near them.

Underneath the cover, inside the clock. The dark, straight lines is where I'll be cutting material away. After establishing the placement of the buttons on the top, I measured up and over from the edges to be able to transpose the positions on the underside.

Another view.

The underside for reference.

I cut the plastic with a hacksaw blade. I protected my hand with some duct tape on one end. You can see my crude hilt for slip protection. :) (The alarm clock top has been removed.)

I basically took some diagonal cuts that were increasingly shallow. I sanded and filed the edges when I got close enough.

 Half way through I realized I could test the buttons on the center hole for the CD player spinner. It worked ok, but was a little loose. When it slipped into the hole I stabbed myself on that sharp corner near the laser symbol. :(

One side finished. The rounded corner was first cut a couple of times with the hacksaw blade, then sanded a bunch.

The other side.

Finished. I sanded all the edges to make them smooth, including the edge on the CD circle that already existed. It was painted silver and it contrasted with the true black plastic color from the cuts nearby.