As summer approached, I still had an ultra-quiet fan and an electronic circuit salvaged from a JNR puff. So I connected these components using a switch and a DC‑DC converter to build a compact, portable fan.

The puff’s PCB is glued to the top and secured with a block. I used a MOLEX connector, but you can also solder directly onto the PCB—there are two pads labeled + and – that extend from the 4V supply.

There are two rear plates: empty and normal. The normal plate significantly reduces noise, whereas the empty plate offers less reduction. In the end, I opted for no plate at all to achieve optimal airflow.

Note: Adjust the DC‑DC converter WITHOUT the fan attached to avoid burning it out by applying too high a voltage.

Optional: Add a 3.7 V battery for some portability (connect the battery’s + and – terminals to “B‑” and “B+” on the JNR PCB).