Very tiny Motor driver with Time-of-Flight sensor

The tiny board is totally self-contained by still have a fear of "reverse voltage application". The applied voltage (taken from rail) is directly connected 3.3 V LDO and Motor driver and reverse voltage may destroy the circuit. Indeed this issue can be easily solved by diode bridge insertion between board and rail. By insertion of diode, we don't need to consider the direction of train (polarity applied to board) and just the train will work by "detected information" and "program inside ATmega328". Ease of use is very important for this kind of board!!

Now two ToF sensors are on board!

General I2S device has some selectable address but the ToF sensor, VL53L0X has a fixed address (non-switchable). Instead, it has "shutdown" pin and we can use it as if CS of SPI. In this board, two shutdown pins (low-active) are connected to D4 and D5 of ATmega328p.

The white line on PCB is a cutting line and we can detach two sensor parts and connect with jumper or flat cable to main board. Of course, still motor driver DRV8830 is on-board!

Sample code to drive two ToF sensors are uploaded in the file area of this project. Actual operation can be found in the following youtube movie,, have fun!

1. Why don't you use WiFi or Bluetooth? They are already prevailed everywhere?
   
   Controlling something immediately (in emergency), can you switch on (wake up from sleep) smartphone or computer in less than 0.1 sec while connection establish and launch application? YES you can raise your hand less than 0.1 sec (even several seconds, still your movement will be faster than clever smartphones. Also, frequency is not infinite resources. Highly congestion easily breaks stable communication, but you can raise your hand even in thousands crowd.
   
2. Why you play with toy? Are you child?
   
   YES, I am surely still child and needs to learn lots. The implementation in train toy is just a "proof of concept" and not final objective (of course, if model train is controlled smoothly, I am very happy though.)
   
   
3. Gesture control is already well established. Why re-inventing wheel?
   
   YES and NO. Commercial-level technology is indeed sophisticated but when we just enjoy technology as a user, it is just "joy" and we will learn nothing. As everyone in hackaday knows how it is difficult to invent something new but for producing something new, we have to know what is possible and what is impossible. Even if ToF device is well known in your company or community or your office, at least I did not know how it works. By making, and also only by making, I believe, we can get knowledge through real experience. Actually, at hackaday, I am trying to share my experience of getting new knowledge and if this share will help your incubation of something new, it is enough.