Topics created by gionata

Here is a solution to create an unique identifier that is based on the device's MAC address (but is not easy to guess and is not the MAC address itself): /** Returns a hashed uint64_t */ uint64_t getHashedInt64(uint64_t u) { uint64_t v = u * 3935559000370003845 + 2691343689449507681; v ^= v >> 21; v ^= v << 37; v ^= v >> 4; v *= 4768777513237032717; v ^= v << 20; v ^= v >> 41; v ^= v << 5; return v; } /** Return a device unique identifier based on device's mac address, eg. 6C4080B51A5D3659 */ String getUniqueId() { uint64_t mac = ESP.getEfuseMac(); uint64_t hash = getHashedInt64(mac); uint32_t msb = hash >> 32; uint32_t lsb = hash & 0xFFFFFFFF; char unique_id[20]; sprintf(unique_id, "%08X%08X", msb, lsb); return String(unique_id); } Calling: getUniqueId() returns something like 6C4080B51A5D3659

@gionata said in cannot open source file "AvailabilityMacros.h" (dependency of "M5EPD.h"): AvailabilityMacros.h AvailabilityMacros.h is a file by Apple. It looks like it's provided by Xcode. Do you have Xcode installed?