MAKERphone 2: A DIY 4G phone with plug-in camera, speaker and prototyping board

CircuitMess, a Croatian electronics kit maker, is selling MAKERphone 2.0, a build-it-yourself 4G phone on Kickstarter that buyers program in MicroPython or Arduino C++ and extend with plug-in hardware. Insert a SIM and it makes real calls and sends real texts. For anyone who tests or tinkers with devices, that is a cellular handset whose software you write yourself.