I've seen a couple other web posts about how to modify the Staples Easy button to play your own message, but now that Radio Shack has closed, some of those posts are no longer valid.
Another method required having a 9-volt battery hanging out the side of the button. Not acceptable, in my opinion.
So, I figured out my own way. You use a pre-made ISD1820 voice recorder chip, already on a board, and strip out what you don't need.
Step 1: Original Board, With 2 Switches Removed.
First, here's an image of the original board. Actually, in this
image, I've already removed the 2 switches at the top for "REPEAT" and "FT" (Feed-through mode) by desoldering them from the back.
Step 2: Jumper the FeedThrough But Not the Repeat Switches. Remove Bulky Items.
In this image, I have simply bent a small piece of copper wire and made a jumper for the "FeedThrough" switch. Jumpering these two holes allows the board to work properly with the microphone and speaker in the correct manner.
The Repeat switch should remain open; no jumper required. You want your message to only play once each time you press the button.
Also, the biggest change in this picture is that I removed the ISD1820PY chip, then desoldered the socket for it, and soldered the IC chip back into place directly. The point of all this is that you have to make the board as slim as possible.
Desolder the microphone. Carefully. You'll need to hook it back up later using jumper wires.
Last, desolder the speaker terminal. Same reason; it's too high.
Step 3: Trim the Board Edges.
As you can see in the first image, the board is too wide. I held the edges of the board on my belt sander to sand/grind them off (just the right and left). As you can see in the second photo, it now fits neatly into the Easy Button case. I desoldered the wires for the batteries and speaker from the Easy Button circuit board. Keep that board; you'll need it for the switch.
Step 4: Still Some Things Sticking Up Too High...
Looking from the side, you can see that the capacitors and the jumper are still too high. In the second pic, you can see I desoldered and removed the P2 jumper and used another little bent copper wire to replace it. Next, the capacitors!
Step 5: Capacitor Mod, and Hooking Up the Easy Button Wires.
Capacitor C5: By desoldering this one from the bottom, I was able to bend it over in place, and use it over. It's leads just barely remained in the holes when it's laid down on the board.
Capacitor C4: Originally a 220uF 35V polarized cap. I replaced it with something I had on hand, a 100uF 16v. The batteries only supply 3.3v on this thing, so I figured 35V was serious overkill on the original. And as it turns out, it works just fine. I laid it out to the side to make room for the board that needs to go back on above this one.
As you can see, I removed the other jumpers for VCC, LED, FT, GND, etc. on the right side of the board (bottom of the picture). The only ones you need are VCC and GND. Solder the battery wires from the underside. I cut little slots in the red plastic 'wall' of the Easy Button to route the wires.
Solder the mic to the board with jumper wires. UPDATE: I thought the mic orientation didn't matter, but I made a second one, and it recorded louder with the mic wired one way over the other. Therefore, either pay attention to which terminal goes to which hole when you desolder it, or hold the wires one way and test, then the other way, and test, to see which works best before you solder them in place.
Same with the Speaker wires; no polarity.
I removed the PlayL and PlayE buttons. You don't need the PlayL one. The PlayE button will get wired to the original top board of the Easy Button. Any of the 4 holes by the PlayE and PlayL words along the bottom of the board will work for one wire; they're all on the same circuit of the board. The other purple wire goes to either of the top 2 holes of the PlayE button.
Step 6: Modify and Hook Up the Top Board.
First, do a little drilling. I used my smallest drill bit to drill a hole on the left side of the board, to the left of the "IO2" marking, just on the left edge of the bare silver pad that's there. Looks messy; sorry.
Cut/scrape the trace that goes from there to the black blob. That blob is the original EasyButton I.C. It shorts your circuit, too.
Solder the other purple wire (top row of PlayE button from previous step) to the silver pad that you just drilled next to. I didn't leave enough silver pad, and had to scrape a little green off the trace that goes to the "OKY" button to make the connection.
The other purple wire (from the bottom of the ISD1820 board) goes to the original "GND" terminal of the EasyButton circuit board.
See that little "2M" surface mount component? Heat it up with your soldering iron, and rotate it out of the way. It shorts your circuit. Don't need it. Remove it completely, if you'd like.
You should be able to use a multimeter to measure the resistance between GND and the drilled&soldered terminal on the left edge to check the button's operation. Resistance should go from infinite (open circuit) to very low (under 100 ohms, I think) when you press the button in the middle.
Before I screwed the board down, I used a fine saw to cut out a notch above the remaining 'REC' button. Make it kind of wide, like I did, to make future steps easier.
Step 7: Drill Access Hole for 'RECORD'
This is a tough one. I wanted the button to still look nice, and you need access to the Record button. You could remove one of the dummy weights in the base of the button, and run wires for a new Record button that mounts on the bottom, but I figured one hole, just big enough for a paper clip, wouldn't look too bad.
I tried to eyeball where the hole should go to make it exactly above the Record button. That's a tough one. I was a little south and west of where I should have placed it, but I solved that problem.
By the way, the button should be completely functional at this point. Try it out. If it doesn't work, start checking all your solder connections!
Step 8: My Solution to the Misplaced Record Hole.
I had my middle-school son try to activate the record button using a paper clip when it was all reassembled. He had a lot of trouble finding the button. Having built it myself, I could find it every time, but I wanted anyone to be able to find the Record button and say, "That was easy", so I came up with this solution.
I cut a wide zip-tie strap and used a small pliers to bend it into a Z shape, trimmed the ends, and hot-glued it to the base of the Easy Button. The other end of the strap rests just above the Record button. It just makes a wider, and much longer, place to press the paper clip to record your own message.
As long as the hot glue gun was out, and things were fully functional, I put dabs of glue at all 4 corners of the ISD1820 board, and on the microphone wire.
The glue on the zip tie, as picture here, rubs the edge of the button. Trim it right to the edge of the red plastic.
Also, one of the 4 posts from the underside of the EASY button needs to be trimmed off (side cutters) so that it doesn't run into the zip tie and keep the Record button pressed all the time.
Step 9: Mic Holes
When everything was reassembled, I did the final test. I noticed that my voice recording was muffled a little compared to when I recorded with everything open. That's to be expected, having it encased in plastic.
So, I took that tiny drill bit again (same one I used for the Record hole), and drilled 4 holes in the top of the button right above where the Microphone is glued inside. I think it cleared up the recording a little bit.
Good luck! If nothing else your soldering and de-soldering skills should be better after this job!