Pesky phone always ringing at just the wrong time? Worried about your phone transmitting data even when it’s off? Make a simple cell phone sleeve from conductive fabric to block RF transmissions.
Not all conductive fabrics block the same frequencies of RF or at the same effectiveness. We found the shiny knit silver plated fabric in the Adafruit shop to be the most effective across wifi and cellular ranges, based on anecdotal testing with various phones.
Layering different types of conductive fabric may yield better frequency coverage, much like having multiple active ingredients in sunscreen. LessEMF does frequency blocking tests on their textiles and reports a graph of their shielding performance– our silver stretch is similar to theirs.