I've gotten out of the flow of writing blog entries, but that doesn't mean we have been idle. There has been progress in the PsyLink sphere along various fronts and I could make several blog posts out of it, but I want to try something new, and summarize everything in a 2022 retrospective post:
Early in 2022, Hackaday released an article on PsyLink (see HackChat & Hackaday Article) which pointed many eyes towards this project, and inspired several follow-up blog posts on other platforms:
PsyLinks into the Wild
Around 30 people have reached out to me following those blog posts, with their own stories, suggestions, and requests for collaborations, for which I am extremely grateful.
I could make arrangements for 8 people in 2022 to get their own PsyLink device for their personal research. (See also: Mass production) This is quite a small number, especially when compared to the spread of software-only projects, which anyone can obtain through a click of a download-button.
But let's look at the bright side: Instead of serving a large number of casual users, I served a smaller number of serious, enthusiastic users of which most have contributed back to the project. Thanks to all the new users for collaborating with me, it was a pleasure so far!
Yet, I'm looking into how to improve that number in the future, perhaps by outsourcing production or through cheaper components, faster assembly, and better advertising.
The design of the PsyLink Prototype 9.2 was finalized in early 2022, and has remained the standard prototype since then.
The modular setup of electrode modules allows custom-tailoring to specific purposes. The photo above shows a dense electrode layout (only 2 electrode modules with 8 electrodes each), but it's also feasible (although cumbersome) to go for an 8-electrode-module setup for maximum flexibility:
AntonX' Electrode Module for MCP6N11
Thanks a lot to AntonX for designing this!
Hopefully I get to test out this board soon and evaluate how it compares to Electrode Module 3.2.
Before ordering it, I wanted to do some polishing: The connector for the signals (S1 through S4) should be at the top rather than bottom, like in Electrode Module 3.2, and the label with the link ("psylink.me/b4") should be on the front side rather than the back side, but that's relatively minor problems and maybe I should just go ahead and order it as it is.
It's not a long-term solution to wear raw circuit boards on the skin. (Or is it?) John Shahbazian saw an opportunity, and designed a 3D-printed case for PsyLink's Power Module:
Thanks John for designing the case, this is a good start! I tried out printing it with the help of a friend successfully and it fits well, though we couldn't quite get the hinge to work.
What I would personally change:
- The hole on the side should rather be two holes, lined up with the holes on the power module PCB itself, so that the rubber band that holds the modules together can easily go through.
- Currently there's only one hole at the bottom, for one of the electrode screws. Since the user can choose which ground electrode they can use (and also for symmetry reasons), there should be 5 holes for all the electrode screws on the power module.
You can get the source files here:
PsyLink GUI for MacOS
John also built a convenient MacOS user interface for plotting PsyLink's EMG signals:
You can find his project PsylinkGUI.py on GitHub. Note that the software is not officially supported.
PsyLink as a Break-Out Board
PsyLink is mainly an EMG sensor, but can be turned into a wide variety of appliances. The power module, e.g. Power Module 4.2, can be used as a battery powered breakout board for the Arduino Nano 33 BLE Sense for any purpose besides neural interfacing.
For example, due to a domestic flooding situation, I wrote some quick-and-dirty code for water detection, plugged a PC speaker and 2 wires onto the PsyLink, and now it makes a siren sound whenever water touches the wires:
And of course PsyLink can also be used to power LEDs for a mobile, battery-powered mood light, see this mastodon post:
This is taking advantage of PsyLink's boost converter without using the Arduino at all:
PCBWay has offered sponsorship for free PCB prototyping to the project, for which I'm very grateful. We haven't actually made any use of this sponsorship so far, but may do so in the future.
By the end of 2022, the project has cost me (Roman, the main author) about 2500€. (excluding lost income)
The total income from donations and PsyLink-related consulting work was about 1850€, which is more than I ever dreamed of earning from an open source project! Yet, it's not quite enough to cover the costs, and certianly not enough to pay my bills. (Not that making money was ever a priority of this project.)
As a result, I am currently looking for paid work as a freelance software developer, so that this project can stay independent and free. If you know of any company in the field of neural interfaces, medical devices or biotechnology that's looking for a freelancer to get some IT work done, let us get in touch!
Hopefully the funding situation improves soon and I can dedicate more time to PsyLink and take on the next steps which are outlined in the wiki. :)
But of course there are now other PsyLink users out there and I am very excited what other contributions will come from the community.
Rochester Institute of Technology's Neurotech Exploration Team (NXT) is currently getting set up with their PsyLink and is looking into getting it to run on Microsoft Windows, and to control a 3D-printed robotic arm with PsyLink.
Good luck to everyone in the open source neural interface community, a big thank you to every PsyLink contributor, and a successful 2023 to you all! :)