Low cost microscope powered by USB


How to add USB power to my 60$ microscope (Bresser junior 20x)


  • Add current limiting resistor
  • Add USB cable
  • Add protective hardboard to the stage


I recently bought a low cost (60$ or 50€) stereo microscope aimed for kids. I wanted to see how it compared to ten to twenty times more expensive versions. It actually performs very well and I am glad that I now have a small microscope at home that allows me to solder miniature components with ease. The only problem was that it used AA batteries for the built in LED. To solve this I simply did the following:

  1. Open the battery compartment.
  2. Add a 220 ohm current limiting resistor to the switch.
  3. Solder the power wires (red and black) from a USB cable to the resistor and the battery connector and close the battery lid.
  4. I added a replaceable piece of hardboard (Masonite) on top of the stage to prevent damage during soldering.
  5. Done, you now have a low cost stereo microscope ready for SMD work and there is no more need to change batteries.

Modified battery compartment beneath the microscope. It is easy to go back to battery operation is needed.

The microscope

Since the stereo microscope is quite small and doesn’t have angled oculars, the ergonomics isn’t comparable with a professional Leica version. It also only offers a fixed zoom of 20x (which is quite high). But except from that it really works perfect. Bresser is a German brand and the junior microscope actually comes with a five year warranty! I have soldered 0402 SMD components with ease and I definitely recommend it to others that want a compact and low cost stereo microscope for private use.

Image showing the 20x magnification (2x 0603 caps and SOT-23-5 3,3V LDO on the Arduino Lernardo). It looks even better IRL (due to stereo oculars and focus) !

You can find distributors all over the world. I live in Sweden and bought mine here.

Bill of Materials (BOM)

1x 220 ohm resistor
1x USB type A cable


5 volts 10mA

Licensing Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

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