So when I wanted to quit smoking I tried an electronic cigarette. They were expensive and didn't produce enough vapor for me. I figured hey it can't be that hard and decided to look into making my own.
Approximate cost not counting batteries is about $12
I took my existing electronic cigarette and hooked it up to a voltmeter and started making notes. I found other electronic cigarette models that had variable voltages so I decided to search through several forums out there to see what range of voltages were being used.
I found that most operate off 5-8vdc with wattage being a little higher than just from the battery alone so battery voltage needs to be higher than what is being used and the amp hours need to be high.
I found that most electronic cigarette mods were using IMR 14500 3.5v Lithium Ion Batteries
Needing to control the voltage I looked at several voltage regulators and came up with the LM317 because it supports the volt range I'm working with. I also wanted to leave room for creating a desktop model.
Nicotine use in the US requires you to be 18 years of age or older but then again this project isn't about nicotine and I didn't use any when I really began to quit smoking.
Feel free to ask questions and/or make suggestions.
Step 1: Application Schematics & Math
As far as the math goes I've done it for you so don't worry too much. I calculated the values based upon 7.5vdc but the intended use is around 6.5 to 7vdc. I left in the overhead because as the batteries get drained you can crank it up.