Project Logs

Collapse

• Reducing expectations...

  Vojtěch Glombíček • 08/14/2024 at 15:56 • 0 comments

  Soon after we built the first prototype, we realized that we had big changes to make.

  Nothing worked as expected. our motor drivers were blowing up, 3D printed gears were unstable and noisy, the robot was getting too heavy.

  We designed a better holder for motors with gearboxes, which looked promising.
  

  
  

  As we were adding everything together, the robot became quite bulky and heavy. The makeshift tires made from bike inner tube didn't have enough grip, the motor drivers were weak... and we didnt even start tackling the biggest challange, that is programming the FPGA.

  We realized that to meet the project deadline, the FPGA has to go.

  So, we started working on a v2 redesign, with an ESP32-S2 controlling the whole operation. The v2 design should be much more integrated, ideally we want to have everything except the sensor on one PCB.

• IR Sensor board

  Vojtěch Glombíček • 06/21/2024 at 14:49 • 0 comments

  It's possible to make a line follower with just 2 photosensors. Such configurations aren't very precise and thus not suitable for high speed. That's why people typically use 4 - 8 sensors.

  That's not enough!

  The bigger the better! To get even better precision and smooth control, we made an array with 32 infrared reflective sensors. FPGAs have a ton of available inputs, so we can afford 32 parallel channels.

  To clean up the signal from our KU163 sensors, we used four 8-channel digital buffers with hysteresis.

  The drawback of this approach is that the sensitivity is set by the resistors in series with the phototransistors, which are not easily adjustable.

  It works quite nicely!

View all 2 project logs