Neon Lamp Tea Light
Introduction: Neon Lamp Tea Light
Updated: Now it's easy to order the PCB for this project directly from PCBWay! Here's the link: https://www.pcbway.com/project/shareproject/Neon_Lamp_Tea_Light.html
Neon lamps, also known as neon glow lamps, are wonderful little bulbs that glow orange when you give them high voltage and low current. Neon lamps are mostly obsolete now; they belong to an era when many electronic devices were supplied with high voltages in order to drive vacuum tubes, and the voltages required for neon lamps were convenient and accessible. Compared to an LED which might have a voltage drop of 3V, a neon lamp's striking voltage on the order of 100V makes it impractical for use in modern circuits, which use transistors instead of vacuum tubes and require much lower voltages.
However, neon lamps look really cute! They deserve better than to be consigned to the history books, thrown out in favor of surface-mount LED's lacking any sense of personality. With this in mind, I decided to create a small, portable neon bulb light. I wanted my creation to have these properties:
* Small (as small as possible)
* Long battery life (1 day at least)
* Wirelessly rechargeable (compatible with any phone charging pad)
Since I wanted to minimize the size of my circuit, I chose to create my first printed circuit board, using Autodesk Eagle. 492
Initially I wanted to make a necklace with a glowing neon lamp, but the size of the charging coil and the height of the inductor on the PCB made that difficult, so it morphed into a tea light. Maybe I'll try to make an even smaller version in the future!
This project requires medium difficulty electronics (regular soldering, surface-mount soldering with solder paste) and medium difficulty hardware (3D printing, sanding/filing). If you want to skip the theory and jump straight to building it, skip to Step 7: Order the PCB!!!. Also, it may take a lot of experimentation to get the wireless charging to work reliably, because the battery is placed so close to the charging coil that it can absorb a good portion of the energy transmitted by the charging pad. A couple tips to deal with this are detailed in Step 14: Troubleshooting.
Let's get to it!
Supplies
Tools:
* Soldering iron and solder
* Multimeter and alligator clips
* 3D printer (I used a QIDI TECH Shadow 5.5S resin printer, you might have some difficulty with the 3D printed threads on the case if you use an FDM printer)
* Wire cutters
* Tweezers
* Surface-mount solder paste (https://www.digikey.com/en/products/detail/chip-quik-inc/SMD291AX10T5/3972568)
* Heating pad for SMD soldering (I used this cheap one)
* Wireless Charging Pad (like this)
Parts:
I strongly recommend ordering this SMD component assortment, since it has nearly all the surface-mount parts you need for this project.
Through-hole Components:
* 1x 1.5M 1/4W resistor
* 1x 18k 1/4W resistor
* 1x 8.2k 1/4W resistor
* 3x 100nF 100V ceramic capacitors (https://www.digikey.com/en/products/detail/kemet/C320C104M1U5TA7303/6562562)
* 3x MUR120 switching diodes 200V (https://www.digikey.com/en/products/detail/on-semiconductor/MUR120G/1482788)
* 1x 150uH 1A fixed inductor (https://www.digikey.com/en/products/detail/kemet/SBCP-80HY151H/9842573)
* 1x LT1073 DC/DC converter chip (https://www.digikey.com/en/products/detail/analog-devices-inc/LT1073CN8-PBF/889104)
* 1x NE-2 Neon Glow Lamp (Anything that says NE-2 should work: https://www.amazon.com/Miniature-Round-Lamps-Diameter-NE-2-0-5mA/dp/B075MPPWFN/)
Surface-mount Components:
* 1206 package resistors:
+ 2x 10M
+ 4x 100k
+ 1x 220
+ 1x 33k
+ 1x 4.7k
* 1x 470 resistor (0603 package)
* 2x 4. 98