OLIA
The Open Lock-In Amplifier
A pocket-sized, USB-powered, open digital lock-in amplifier, based around the Teensy 4.0. Features include:
- Internal or external referencing
- 10 Hz - 50 kHz frequency range
- Dynamic range of ~106 (using input preamp)
- -1.6 V to +1.6 V bipolar input
- Variable input gain (from 0 to 64)
- Configurable analogue output
- Both exponential and synchronous filtering, with adjustable filter time constant
- Parallel calculation of higher harmonics
- 5 V power passthrough
- Simple, powerful frontend
- Ultra low unit cost (~£30)
- Simple construction (all hand-solderable)
A paper describing the device's design, construction, features and use, alongside test data is available here: https://doi.org/10.3389/fsens.2023.1102176.
This repository includes a parts list and build guide alongside some simple usage instructions. CAD and CAM files for the device's PCB are available in the boards directory, and source code for the device's firmware is available here. A simple python frontend is provided here, but those who wish to build their own interface can refer to the serial reference.
For those wanting to make optical measurements, we provide designs for an optical DC servo add-on board which can be used to compensate for and reject ambient light.