Hi
I am aware that there are topics out there that partly cover this question, but even after a lot of trying and tinkering i was not able to achive my goal.
I try to transmit 2-3 BSSIDs from WiFi-APs with LoRa (TTN). I am able to extract the BSSID of nearby Wifis (WiFi.BSSIDstr(i) or WiFi.BSSID(i)).
In order to use the Function ttn.sendBytes() i need an array of bytes. But here comes the issue: I was not able to either loop over the BSSIDstr-return, remove the : and convert them, nor have i been able to concatenate WiFi.BSSID into one variable.
To be honest, i have an absolute mess between these variable-types. I come from php and ruby and do - even while trying hard - not understand what to use when...
I would be really happy if someone could give me a hint how to proceed!
Chris
p.s is there a "high-level" language available for esp32 that covers such kind of things? i tried to google it, but results were non-promissing
p. p.s., here's my code. but actually, it does not really make sense to look at it. it's really just try and error and every time i change something, it only gets worse
#include <TTN_esp32.h>
#include <WiFi.h>
const char* devAddr = "asdf"; // Change to TTN Device Address
const char* nwkSKey = "asdf"; // Change to TTN Network Session Key
const char* appSKey = "sadf"; // Change to TTN Application Session Key
RTC_DATA_ATTR int bootCount = 0;
uint8_t b[18]; // = {};
int i;
TTN_esp32 ttn ;
void printHex(uint8_t num) {
char hexCar[2];
sprintf(hexCar, "%02X", num);
Serial.print(hexCar);
}
void setup() {
Serial.begin(115200);
++bootCount;
}
void loop() {
if (bootCount % 20 == 0) {
//regular report
} else {
Serial.println("begin wifiscan");
if (true) {
String bssids = "";
String a;
int numberOfNetworks = WiFi.scanNetworks();
if (numberOfNetworks > 1) {
if (numberOfNetworks > 3) {
numberOfNetworks = 3;
}
char cstr[6 * numberOfNetworks];
int reslength = 12 * numberOfNetworks + 1;
for (int i = 0; i < numberOfNetworks; i++) {
a = WiFi.BSSIDstr(i);
a.replace(":", "");
bssids += a;
Serial.println(WiFi.BSSIDstr(i));
strcpy(cstr, bssids.c_str());
///Serial.println(cstr);
}
for (int y = 0; y < sizeof(bssids) / 2; y++) {
//uint8_t tmp = sscanf(bssids.substring(0,2),"%x");
//b[y] = (uint8_t)strtoul(cstr[0], NULL, 10);
}
}
/*for (i = 0; i < sizeof(b); i++) {
printHex(b[i]);
}*/
//ttn.sendBytes(b, 16);
}
delay(10000);
}
}
can you provide a link to a description of the format of the data packet you are either receiving or transmitting, or are you just transceiving ascii data.
Well, i try to send up to 3 mac-addresses (BSSIDs) which are 6 bytes or 12 characters each. I'd like to concatenate these into one payload in order to save airtime and battery.
ttn.sendBytes seems to accept uint8_t as a datatype which i don't really know how to fill with up to three WiFi.BSSID():
Thanks a lot. The last issue i was able to figure out myself. BSSID() is returning a pointer (?) and i had to use memcpy in order to store it in "your" mac1/2/3 var:
#include <TTN_esp32.h>
#include <WiFi.h>
const char* devAddr = "asdf"; // Change to TTN Device Address
const char* nwkSKey = "asdf"; // Change to TTN Network Session Key
const char* appSKey = "asdf"; // Change to TTN Application Session Key
uint8_t mac1 [6];
uint8_t mac2 [6];
uint8_t payload[12];
TTN_esp32 ttn ;
void prep(void)
{
int i = 0;
for (unsigned n = 0; n < 6; n++)
payload [i++] = mac1 [n];
for (unsigned n = 0; n < 6; n++)
payload [i++] = mac2 [n];
}
void setup() {
Serial.begin(115200);
WiFi.scanNetworks();
Serial.println(WiFi.BSSIDstr(0));
memcpy(mac1,WiFi.BSSID(0),6);
memcpy(mac2,WiFi.BSSID(1),6);
prep();
ttn.begin();
ttn.personalize(devAddr, nwkSKey, appSKey);
ttn.sendBytes(payload, sizeof(payload));
}
void loop() {}
Now i will have to build the main code around it, but that should be doable
No. Sorry for the confusion. These are just obfuscated TTN access-codes used in ttn.personalize()
WiFi.BSSID(i) returns the MAC of each Wifi found by WiFi.scanNetworks.
I will search for the three strongest or skip if less than 2 are closeby.
These macs will be sent over lora to an mqtt-client which will ask google location api where (approx) these wifis are. This makes a simple, (hopefully) power-efficient device which will help me find my stolen (or lost on a saturday night :-)) bike. In a more or less urban area this should be working quite well, but lets see in real life...
