This work presents a technique to produce random bits by exploiting single-photon time of arrival. Two quantum random number generator (QRNG) devices based on the field programmable gate array (FPGA) technology are presented: Randy, which uses one discrete single-photon avalanche diode (SPAD), and LinoSPAD, which uses a complementary metal-oxide semiconductor (CMOS) SPAD array, along with a time-to-digital converter (TDC). Postprocessing procedures are explained in order to extract randomness, taking care of SPAD and TDC nonidealities. These procedures are based on the application of Peres [Ann. Statist. 20, 590 (1992)] and Zhou and Bruck [arXiv:1209.0726] extraction algorithms. Achieved generation rates are 1.8 Mbit/s for the Randy device and 310 Mbit/s for the LinoSPAD device.