Introduction: Cigarette Socket to USB Conversion

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About: If you have any questions about my Instructables just ask me Kaltol1994@gmail.com Twitter and Snapchat Kaltol1994

A few months ago I bought a brand new USED car! For a low price I bought a BMW convertible in pretty good condition but being a 2003 the cigarette lighter socket had rusted out. Before realizing the rust was more than just the surface the phone charger I bought was now of no use. With the aid of a 3D printer, a caliper and a little CAD I made my own solution. I didn't take as many pictures through out the process, none during soldering, but I'll do my best to make it easy to grasp.

  • What you will need:
  • Wire - I used some 22 gauge stranded.
  • Heat Shrink - Good stuff.
  • Soldering Iron & Solder.
  • 3D printer or 3D printing service.
  • Socket set or Wrench - Used to disconnect car battery (This may cause some cars to go into anti-theft mode)
  • Caliper
  • CAD software.
  • A small hammer - To tap the circuit into the sleeve

Not including printing time (Mine took about four hours) everything should be done in 90 minutes or less.

DISCLAIMER: I did this project on my own, this is merely a guide to display what I did and how I did it. I do not claim any responsibility for any damages or injuries you cause to yourself, others or property by trying to replicate this project.

Step 1: Disassembly

This will be different for every car, just search "how to replace cigarette socket" and you should find what you need. Luckily BMWs are easy to take apart, I had everything apart in minutes.

Step 2: Measuring the Outer Diameter and Charging Circuit.

Using a caliper I measured the outer diameter of the metal socket and the inner diameter of the socket it fits into. I measured both to see how much of a gap there was in the first place, this helps when you need to give your print some play. I then measured the width of the circuit board and its thickness I then measured the depth. I also measured the USB sockets. I created a tube with a square hole for the ports and circuit and slits for the circuit board. It fit like a sleeve, but I didn't think of every detail...Read for more!

Remember: The spring at the end is positive while the curved piece of metal that touches the walls of the socket is negative.

Step 3: Design

You make the model with a few different methods, I made a profile and did a revolved base followed by an extruded cut. You could also make the outer circle in the sketch in the first picture, extrude it to 40mm then sketch a 28mm circle 0.6mm in the opposite direction then make the rest of the sketch and make an extruded cut. I could go on for a while. It's not a very hard shape, it's the measurements that posed the only challenge.

Step 4: Printing & Fitting

Remember how I said I thought of almost everything? I printed the sleeve, and it fit like a dream! Except for the toroid magnet. I had to do a little Dremeling here and there but it fits and looks great, people think my car came this way! Since all cigarette lighter sockets are the same size this should work for every car, the only variable being the circuit.

Step 5: Installation

Like dis-assembly this will vary for everyone, except for one key point, remember to put your heat shrink on before you splice your wires and remember to run the wires through the hole in your console before splicing and soldering, I promise you'll scream less this way (I raged a fair amount.) Now reassemble and enjoy!

One problem I had which may had been related to my phone sustaining some water damage, it would only charge when my screen was off (but wall chargers and USB ports on computers worked fine) but it now works fine not sure what it was, either the circuit or my phone, while this may look like a lot all we've done with this project is eliminate a socket. Everything works fine now so I'm happy, you will be too. If the circuit you use has great reviews you needn't worry.