I was heavily involved with the local soccer community, and as a coach/referee I carried my own detector that I paid less for a ready to go version than this DIY shield. I was not going to depend on someone else's gear functioning when these were so cheap.
Got a link to that detector? The cheapest self-contained lightning sensor in a portable form factor I know of nowadays is the Acurite 02020 and it's around ~$50 nowadays.
That's interesting. That's the same one I have, but I only paid $27.99 for it. I couldn't remember what the model was, but Amazon shows that I purchased that model and clicking the View Order link it shows $27.99. I guess I bought at the right time??? Maybe it's tariffed to death?