Free STIM files are a fantastic resource for the curious mind, but they are not plug-and-play toys. Treat each file like a prescription: verify the source, inspect the code, and listen to your body.

Always consult with a medical professional before beginning any form of electrical brain stimulation.

Disclaimer: This article is for informational purposes only. DIY brain stimulation carries risks, including skin burns and mood alteration. The author does not endorse using unverified STIM files.

PsychoPy is an open-source stimulus presentation tool. Their Pavlovia repository contains free to use visual and auditory STIM files for common tasks (Flanker task, Go/No-Go, Oddball paradigm). You can export these as .psyexp and convert them.

Just because a file is free does not mean it is safe for you.

Step 1: The Text Editor Test Before loading a .stim or .json file into your device, open it in Notepad (or TextEdit). Look for anomalies:

Step 2: Compatibility Check Most free STIM files are written for Focus devices or DIY Arduino-based stimulators. If you use a proprietary device (like a Halo Sport), you will likely need to use a file converter or transcribe the parameters manually.

Step 3: The "Sham" Rule Always have a Sham (placebo) file loaded. A good free STIM file includes a Sham version that ramps up for 30 seconds and then drops to 0mA. You should never run an active file on a new montage without a blinded Sham test first.