A TTL-controlled light switch designed to blank monitor displays for use in behavioural experiments.
Note: This device modifies existing monitors. Some tuning may be required depending on the model.
In systems neuroscience research, you want to present visual stimuli to animals without damaging the sensors you use to record neural activity. e.g. photomultiplier (PMT) for multiphoton imaging. Monitor blanking is a commonly used approach to minimize monitor light contamination by blanking the monitor backlight during the imaging pixel acquisition. The monitor turns on only during flyback periods of the fast-scan axis. Another approach is to use a 3D-printed cone.
- Electrically isolated TTL input (up to 1 MHz)
- Sub-1 µs switching time
- Adjustable backlight brightness
- Forced-on switch for testing/debugging
- Supports up to 15 W output power
View the complete electronic design project online via Altium 365 Viewer.
Connect the monitor to your computer and adjust the resolution, scaling, etc. On Windows, navigate to Settings > System > Display. Pressing the Forced ON button will enable debug mode, where the monitor functions as a standard monitor without digital pulses.
Once the monitor is detected and configured (also disable the debug mode), send digital pulses from your fast-axis mirror through the Trigger BNC connection. A low signal will blank the monitor, and a high signal will allow backlight illumination. (hence, you cannot see anything if you are not sending TTL pulses.) Here are example functions for ScanImage users to generate and send monitor blanking TTLs. BaselLaserMouse/ScanImageTools
The luminance of the monitor can be measured using a luminance meter (e.g. LS-100, Konica Minolta) or a light sensor (e.g. Photodiode, Champalimaud Foundations’s Hardware Platform).
The blanking driver circuit is designed to support a wide range of monitor backlight types. However, to ensure optimal performance, you may need to fine-tune the VLED voltage.
- Press the pushbutton to force the monitor ON, then use the trimmer R9 to adjust the VLED until the backlight reaches the desired brightness level.
- The output voltage VLED can be adjusted within the range of 41 V to 61 V.
The recommended VLED is at least 2 V higher than the forward voltage of the backlight panel.
To access the source CAD projects:
- Altium Designer 24 or newer
Academic licenses available via Altium Education - Autodesk Inventor Pro 2025 or newer
Academic licenses via Autodesk Education
Sainsbury Wellcome Centre hardware is released under Creative Commons Attribution-ShareAlike 4.0 International.
You are free to:
- Share — copy and redistribute the material in any medium or format
- Adapt — remix, transform, and build upon the material for any purpose
Under the following terms:
- Attribution — Give appropriate credit, link to the license, and indicate changes.
- ShareAlike — Distribute your contributions under the same license.
- No additional restrictions — Don’t apply legal or technological measures that prevent others from doing anything the license permits.
For the full legal text, see LICENSE.
@ARTICLE{Leinweber2014-nf,
title = "Two-photon calcium imaging in mice navigating a virtual reality environment",
author = "Leinweber, Marcus and Zmarz, Pawel and Buchmann, Peter and Argast, Paul and Hübener, Mark and Bonhoeffer, Tobias and Keller, Georg B",
journal = "Journal of visualized experiments: JoVE",
number = 84,
pages = "e50885",
month = feb,
year = 2014,
url = "https://app.jove.com/t/50885/two-photon-calcium-imaging-mice-navigating-virtual-reality",
doi = {10.3791/50885}
}
- Fork the repository
- Create a feature branch
- Make your changes
- Submit a pull request
- Author: @DCisHurt
- Email: yuhsuan.chen@ucl.ac.uk
- Website: FabLabs