Skill level: Medium. No computer programming necessary.
Time: First one takes about 8 hours, then about 4 hours each once you get the hang of it.
Green: Recycled broken radio, re-purposed LED's and batteries from tea lights.
Materials cost about $13.85 including batteries.
Step 1: Tools Required
2. Medium flat-head screwdriver
3. Small "nibbler" wire cutters
4. Small needle-nose plyers
5, Small flat-head screwdriver
6. Small phillips-head screwdriver
7. Soldering iron
8. Glue gun (optional)
I also used a small coping saw for flat cuts that were difficult with the rotary tool.
Step 2: Parts List
1. An old, broken transistor radio. This Instructable is for a side-dial thumb wheel model, but you can build one with a center-dial unit too by getting creative with the switch and LED placement.
2. A sound card that records and plays back audio. For this project, I used a dual-sample circuit board from Electronics 1-2-3 that costs $7.55, here's a link: http://tinyurl.com/cpbtyk .
3. Two LED tea lights that flicker with an amber glow.
4. Solder and solder remover or wire braid.
5. An eight inch length of 9-conductor ribbon cable or equivalent. Easily removed from any broken computer. I like the rainbow colors for easy wiring and a pretty look if someone opens the case.
6. Two 3-Volt CR-2035 dime batteries and holder. You can sometimes re-use the batteries that came inside the tea lights, as well as the battery holders if you want to trim them down and connect them together in series for 6 volts. Otherwise, good prices on eBay. You could also go with the original 9-volt battery instead and put in a voltage regulator circuit to bring it down to 6 volts. I chose to keep things simple as the current draw is minimal.
7. One 3/4 inch nylon bushing or two washers glued together for greater thickness.
8. Goop or Shoe Goo brand adhesive with applicator tip cut to smallest opening.
9. Electrical tape.
10. Masking tape.
Step 3: Open Case
Step 4: Remove Circuit Board and Speaker
Step 5: Grind Radio Circuit Board
Using a rotary tool, grind off the solder and copper clad from circuit board at the two locations.
Step 6: Remove Switches From Sound Board
The switches are slightly oblong rectangles so choose a side where two of the leads are closest together and clip them off leaving the two leads on the opposite side intact.
Step 7: Glue in Switches
Then apply more adhesive to the backs and sides of the switches being careful not to glue the button part so it won't press. Be sure to leave the two contact leads exposed.
Apply some masking tape to hold the switches in place for 1/2 hour, then remove it as well as the shims and let dry overnight.
Step 8: Connect Sound Board
Red: V6+ (Positive voltage in)
Brown: Speaker pin 1
White: Speaker pin 2
Blue: Switch 1, terminal 1
Green: Switch 1, Terminal 2
Yellow: Switch 2, Terminal 1
Orange: Switch 2, Terminal 2
With the relocation of the switches adjacent to the thumb wheel, you can start to see that this you are merely creating jumpers for the switches themselves.
Cover the bottom of the circuit boards with electrical tape and trim the sides.
Step 9: Connect Speaker
Locate the brown and white wires coming from the sound board and solder the remaining ends of the brown and white wires to the two terminals.
Step 10: Connect Battery Holder
Cut and strip an eight inch length of both red and black wire. Solder the red wire to the positive "+" terminal. Solder the black wire the the negative "-" terminal as well as the black wire that is connected at the other end to the sound board.
Fold back the terminals so they are flush with the bottom and cover them with electrical tape.
Step 11: Hook Up the Thumb Switch
Cut and strip an 8 inch piece of red wire and solder it as well as the other red wire connected to the sound board to the remaining terminal on the thumb wheel switch.
Step 12: Disassemble Tea Lights
Using a small flat-head screwdriver, pry the bottom out of the tea light.
Remove the battery
Bend the leads beneath the batteries to release the LED lead.
Turn over and unsolder the other side of the LED from the switch.
Do this on both tea lights to remove the LED's.
Step 13: Solder the LED's
Now solder the remaining lead of the LED you are working with to the other led on it's side with the flat end. You are creating a "series" circuit so the two 3 Volt LED's combine to make a 6 volt circuit that can handle the power.
Solder the remaining lead of the second LED to the red wire coming from the thumb wheel switch.
Wrap the exposed leads of the LED's with electrical tape.
Step 14: Install Nylon Crescent
Locate your original pencil mark on the tuner thumb wheel. Using the rotary tool, flatten the edge of the wheel to match the nylon crescent.
Glue the crescent to the flat spot of the wheel.
What you've created is a "bump" on the wheel that engages the switches as it passes them. This way, you don't have to install modern buttons on the outside of your old radio.
Trim the "bump" with the rotary tool for the right width so it engages the switches without pushing them out of position.
Step 15: Solder Wires to Switches
Blue and Green to Switch #1
Orange and Yellow to Switch #2
Step 16: Remove Radio Parts
Step 17: Glue Components
Glue the circuit board and battery holder to the radio circuit board (the side without the thumb wheels).
Test-fit the back cover to make sure there or no blocked screw holes or obstructions to closing it up.
Step 18: Glue in LED's
Step 19: Re-assemble
Re-insert screws to hold circuit board and speaker in place.
Step 20: Record Time Travel Broadcasts
Slide the switch on the sound board to the "REC" position to record.
Cue up the sound you want to play from your computer, and position the radio about six inches from your computer speaker set to play back at conversational volume.
Turn the tuner thumb wheel to engage one of the switches and hold it there until you want it to stop. It will allow a little over 20 seconds maximum for each recording.
Now cue up your second audio message on your computer, turn the thumb wheel to engage the second switch and hold to record.
Step 21: Time Travel!
Replace the back cover of the case and snap into place.
Turn the thumb wheel to engage either switch to play back your sounds and travel through time!
Step 22: Epilog
If you are making your Transistor Radio Time Machine as a gift, here's a few suggestions to make it special and specific to the recipient:
- Find out their birthday and date. Record yourself speaking as an old-time radio news announcement about the day of their birth and how very important it is.
- Find and record a sports game highlight of their favorite team on the year they were born.
- Record a pop tune they used to love as a child.
- Find an old ad of a product brand that is still made that you know they use.
- Record a hint for a treasure hunt.
- Record your voice doing an impression of them talking to themselves from the future.
"What is this, some sort of evil "Si-Op"? The radio is talking directly to me, and it KNOWS i'm LISTENING! Brilliant!"
Have fun, and please feel free to post your comments or questions here. I'm always looking for new ways to tinker with this stuff.
I make lots of interactive art, big and small, for the Burning Man art festival. Please check out my website at www.MutantVehicle.com for other weird stuff.
Be well and do strange things!