Introduction: USB FM Bug

About: Exploring, searching, hacking... is my life. I am working on radiation, high voltage, programming, 3d drawing, hacking, music and...


This is a modification project for a 2V-9V FM Transmitter Module. It will work with USB power, a small antenna at the end.


Operating Voltage: DC 2V- 9V

Work current: 10 mA - 50 mA

Reference distance: open ground 100 meters, 10-30 meters indoor environmental obstacles (3v voltage test, increasing the voltage from the greatly increased)

Output power: 3 DBM - 15 DBM

Operating frequency: 85MHZ --- 115MHZ (usually between 99-101 boot default frequency)

Receive way: as long as the 88-108MHz FM radio can receive, with FM feature phones.

Frequency adjustment: adjustable capacitor

Output Impedance: 50 ohms

Size: 18 mm * 10 mm * 3 mm

ANT connecting antenna length: standard 75 cm

Frequency regulation accuracy: < 0.1 MH

What do you need:

A FM transmitter module (Smallest PCB one on ebay): 4$

A USB Flash case: From junk

Soldering Iron


Hot Glue

Small Antenna from old Java Based Phone

USB Male

Step 1: Soldering

This is the longest and hardest part. We need to decide the shape of our module. I bended small pins and tried a lot for best result. You can look at pictures. Care about polarity when soldering usb pins.

1.In the first picture you can see my antenna unit.

2.Hotglued antenna to make it stand.

3.Final modification. Best result.

Now we can put our module into USB Flash Case

Step 2: Assembly

1.Put module into case and make it stay with hotglue.

2.Attach antenna and plug to your power supply.

3.Test it!

Step 3: What Can You Do? and Extras

You can hide it easily. Flowers and ornaments are good places.

You need to find a smaller power supply.

You can listen your baby when you go to neighbour.

You can communicate with your friends in yor area.

You can use it like a small radio station.

This module also works with 3.7v batteries. I made a usb pluggable battery for this project. Now our pocket FM radio is ready for using anywhere!

Thank you for your interest.

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