some tester codes and PING_PONG implementation.
idf.py build
idf.py -p [PORT] flash monitorESP32 promiscuous mode sniffer.
GY-511: Need to connect GND to GND, SDA to GPIO21, SCL to GPIO22, VIN to 3V3.
MPU6050: Need to connect GND to GND, SDA to GPIO21, SCL to GPIO22, VCC to 3V3.
Can change GPIO pins in the source code.
Tester codes for GY-511 (magnetometer and accelerometer) and MPU6050 (gyroscope and accelerometer).
I used complementary filter for MPU6050. For GY-511, I had a problem getting the heading angle out of the x,y,z raw data. atan(y/x) seems to be not working.
Previous try of broadcasting UDP packets.
Between M_recv and M_send: Need to connect GPIO4 to GPIO5, GPIO5 to GPIO4, GND to GND.
Between W_recv and W_send: Need to connect GPIO4 to GPIO5, GPIO5 to GPIO4, GND to GND. (same)
Works as follows:
M_send_node is broadcasting raw packets. W_recv_node is in promiscuous mode and can sniff the packets with RSSI values. If the RSSI value is high enough, a UART message is sent to W_send_note to send a raw packet back to M_recv_node. RSSI value is in the UART message, and sent back to M_recv_node. M_recv_node responds to the RSSI value in the message and change its frequency of LED blinking. (For LED part, use "LED")
M_recv and W_recv are in promiscuous mode (WIFI_MODE_NONE), and M_send and W_sned are in AP mode (WIFI_MODE_AP).
Possible improvement: Maybe we can reduce the system to 3 nodes by sending UDP packets back to M, so there is no need to have M_recv_node. The purpose of sending raw packets is to get RSSI values. But to receive UDP packets, M and W must be under the same network, which may be impossible.
In PING_PONG, the M_recv node responds to RSSI values. Freq_based is a version of PING_PONG where the W_send node sends many raw packets back to the M_recv node, where the frequency is based on the RSSI value. This change could improve the stability of the system.
Issue: Now, the M_recv node seems unable to receive a lot of raw packets. I tried IRAM_ATTR and removed the printfs in the callback, but this won't help. The most likely cause is the slow speed of promiscuous mode.
A working LED version of PING-PONG. Connect a LED onto GPIO32, it will blink at a frequency inversely proportional to the distance between M-node and W-node.
esp_gy511.h - for GY-511
esp_gyro_accel.h - for MPU6050
esp_raw_packet.h - for preparing and sending raw packets.