424 BDF1000 Line folower
424 : BDF1000 Line folower
- Author: Belkacem BENADDA
- Description: a logic circuit and PI controler for the BFD1000 Line follower sensor dedicated to tinytapout SKY26a
- GitHub repository
- Open in 3D viewer
- Clock: 50000000 Hz
How it works
This Solution reads input from the BFD1000 5-channel IR to control the robot motor wheels. The sensor has 5 inputs, S1, S2, S3, S4, S5, giving a 1 output for blanc color and 1 for white color. The CLP pin outputs a 1 when a collision occurs, and the near pin outputs a 1 when an obstacle is detected. The outputs are the left and right motors' ON/OFF signal, and the direction control. We also add velocity since we are doing PWM directly from the clock pin.<br>
| S1 | S2 | S3 | S4 | S5 | CLP | Near | EnL | DirL | EnR | DirR | Observation |
|---|---|---|---|---|---|---|---|---|---|---|---|
| x | x | x | x | x | 1 | x | 0 | x | 0 | x | Stop |
| x | x | x | x | x | x | 1 | 0 | x | 0 | x | Stop |
| 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | Forward full speed |
| 1 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | x | 1 | 1 | Low correction left |
| 1 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | x | 1 | 1 | High correction left |
| 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 1 | rotate left |
| 0 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 1 | full rotate left |
| 1 | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 0 | x | Low correction right |
<br> The logical equations are then:<br> Left motor control:<br> EnL = (s1&s2&s3&~s4)|(s1&s2&s3&~s5)|(s1&s2&~s3&s5)|(s1&s2&~s4&s5)|(~s1&~s2&~s3&~s4&~s5)|(~s1&s3&s4&s5)<br> DirL = (s1&s2&s3&~s4)|(s1&s2&s3&~s5)|(s1&s2&~s3&s5)|(s1&s2&~s4&s5)|(~s1&~s2&~s3&~s4&~s5)<br>
Right motor control:<br> EnR = (s1&s2&s3&~s5)|(s1&~s2&s4&s5)|(s1&~s3&s4&s5)|(~s1&~s2&~s3&~s4&~s5)|(~s1&s3&s4&s5)|(~s2&s3&s4&s5)<br> DirR = (s1&~s2&s4&s5)|(s1&~s3&s4&s5)|(~s1&~s2&~s3&~s4&~s5)|(~s1&s3&s4&s5)|(~s2&s3&s4&s5)<br>
<br><br>
How to test
Simulations are performed on the NEXYS4 FPGA board using the AMD Vivado tool. Connect the BFD1000 sensor as follows:
- S[5:1] to ui_in[4:0]
- Clip to ui_in[5]
- Near to ui_in[6]
- PWM to ui_in[7] in case you want to add speed control
The outputs EnR/L and Dirr/l are connected to the right and Left motor drivers, respectively. LEDs can also be used to analyze the control tasks on motors.
External hardware
BFD1000 5-channel line follower sensor, two motor drivers with LED display
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | S1 | EnL | Kp[0] |
| 1 | S2 | DirL | Kp[1] |
| 2 | S3 | Out1L | Kp[2] |
| 3 | S4 | Out2L | Kp[3] |
| 4 | S5 | EnR | Ki[0] |
| 5 | Clip_Near | DirR | Ki[1] |
| 6 | PWM | Out1R | Ki[2] |
| 7 | sel | Out2R | S_Ki |