Introduction: Inductive Angel Tea Lamp

By Greg Zumwalt
About: Our grandkids keep me busy!

An inductively rechargeable version of my Angel Tea Lamp design. When the angel is placed on its charging base, the tea light LED extinguishes and the angel internal lithium battery is charged. When the angel is removed from its charging base after charging, the tea light LED illuminates for hours.


Designed using Autodesk Fusion 360, sliced using Ultimaker Cura 4.12.1, and 3D printed in PLA Ultimaker S5s.

Supplies

  1. Soldering iron and solder.
  2. Ohmmeter.
  3. Thick double sided tape.
  4. Thick cyanoacrylate glue.
  5. Red and black AWG 22 wire.
  6. Heat shrink tubing.

Step 1: Parts.

I acquired the following parts:

  1. One Adafruit inductive charging set (Adafruit part number 1407).
  2. One mini lithium battery charger (https://www.amazon.com/gp/aw/d/B0BRXYZTWN?ref=ppx_pop_mob_b_asin_title&th=1)
  3. One 3.7 volt 200ma lithium battery (https://www.amazon.com/gp/aw/d/B09WN9W5YV?psc=1&ref=ppx_pop_mob_b_asin_title).
  4. One plastic normally closed reed switch with magnets (https://www.amazon.com/gp/aw/d/B088CQL44X?psc=1&ref=ppx_pop_mob_b_asin_title).
  5. One 9VDC 400ma power supply.
  6. One angel tea lamp LED (3VDC).

I 3D printed the following parts at .15mm layer height, 20% infill with no supports:

  1. One "Angel Base Cover.stl".
  2. One "Angel Base.stl".
  3. One "Angel_Tea_Light_Small.stl".
  4. One "Charger Base Cover.stl".
  5. One "Charger Base.stl".

Prior to assembly, test fit and trim, file, sand, etc. all parts as necessary for tight fit . Depending on the colors you chose and your printer settings, more or less trimming, filing and/or sanding may be required.

Attachments

Step 2: Assemble the Charging Base.

To assemble the charging base, I performed the following steps:

  1. Slid the power supply wires through the hole in the side of "Charger Base.stl" and into the center cavity.
  2. After removing the red and black wires from the charger set transmitter board, soldered the positive (+) power supply wire to the charger set transmitter board positive (+) connector, then soldered the negative (-) power supply wire to the charger set transmitter board negative (-) connector.
  3. Pressed the charger set board and coil into the charger base.
  4. Pressed two read switch magnets into the magnet pocket in "Charger Base Cover.stl".
  5. Pressed the charger base cover assembly into the charge base assembly (glue will be used to secure the cover after assembly and test).


Step 3: Assemble the Angel Base.

To assemble the angel base, I performed the following steps.

  1. Pressed one normally closed reed switch into the reed switch cavity in "Angel Base.stl".
  2. After placing the angel base assembly into the charger base, using an ohmmeter, slid the reed switch side to side in the angel base reed switch cavity until the reed switch opens when on the charger base and closes when off the charger base.
  3. Pressed the charger set receiver board and coil into the angel base.
  4. Soldered the charger set receiver board positive (+) and negative (-) wires to the lithium battery charger positive (+) and negative (-) connectors respectively.
  5. Secured the charger set receiver board to the angel base using a strip of thick double sided tape.
  6. Secured the mini lithium battery charger to the charger set receiver board double sided tape.
  7. Soldered one of the reed switch wires to the lithium battery charger "OUT-"connector.
  8. After removing the angel tea lamp LED from the tea lamp, soldered a 40 mm length of red wire to the LED anode lead, then soldered a 40mm length of black wire to the LED cathode lead, then insulated both solder joints with heat shrink tubing.
  9. Soldered the LED red wire to the "OUT+" connector on the lithium battery charger.
  10. Soldered the LED black wire the remaining reed switch wire.
  11. Soldered the lithium battery pack red wire to the lithium battery charger "B+" connector, then soldered the lithium battery pack black wire to the lithium battery charger "B-" connector.
  12. Secured the lithium battery pack to the lithium battery pack charger using a strip of thick double sided tape.


Step 4: Final Assembly.

For final assembly, I performed the following steps:

  1. Pressed "Angel_Tea_Light_Small.stl" into "Angel Base Cover.stl".
  2. Pressed the angel and cover into the angel base assembly.
  3. Placed the angel assembly onto the charger assembly making certain the tea light LED extinguished.
  4. With everything assembled and tested, applied small drops of glue between the angel base and angel base cover, and the charging base and charging base cover, to secure them in place.

And that is how I 3D printed and assemble "Inductive Angel Tea Lamp."

I hope you enjoyed it!