Imagine that we want to design a tiny machine capable of sensing an external chemical concentration and move, for instance, upgradient. Our machine is so small that it cannot detect concentration gradients and so primitive that it cannot regulate its speed, which remains constant. If we assume that the machine has memory, as it moves in one direction it can compare the chemical concentration at different locations, compute effectively the gradient, and switch direction if it moves downgradient or keep its current direction if it moves upgradient. This is in a nutshell the chemotactic strategy used by some bacteria as E. coli. Here, we propose a different strategy, arguably simpler: we equip the particles with a clock that regulates the switching direction of the particles and show that there are specific clock designs, whose period depends on the chemical concentration, that allow guiding our tiny machine upgradient. We argue that the use of clocks may prove key to design chemotactic robots and to understand some bacterial systems.