I my case I am trying to act my device as beacon and tried to set the txpower I want my beacon to get disappear from Locate App whenever I am out of its range so I tried setting the txpower distance for 1 meter but even after I go out of range of my beacon let's say 3-4 meter I still see my beacon on Locate App even though I have set it for 1 meter because it has rssi power which always varies which actually does the signal transmission part, I tried setting hardcode rssi power but still after seeing the beacon on Locate App it varies and when I am at distance of 3-4 meter I am able to see my beacon on Locate App.
Below is my code where I am trying to set my beacon.
Beacon beacon = new Beacon.Builder()
.setId1("2f234454-cf6d-4a0f-adf2-f4911ba9ffa6")
.setId2(String.valueOf(major))
.setId3(String.valueOf(minor))
.setManufacturer(0x004C)
.setTxPower(-84)
.setRssi(-49)
.setDataFields(Arrays.asList(new Long[]{0l}))
.build();
BeaconParser beaconParser = new BeaconParser()
.setBeaconLayout("m:2-3=0215,i:4-19,i:20-21,i:22-23,p:24-24");//
beaconTransmitter = new BeaconTransmitter(this, beaconParser);
beaconTransmitter.startAdvertising(beacon, new AdvertiseCallback() {
#Override
public void onStartFailure(int errorCode) {
Log.e("Class", "Advertisement start failed with code: " + errorCode);
}
#Override
public void onStartSuccess(AdvertiseSettings settingsInEffect) {
Log.i("class", "Advertisement start succeeded."+settingsInEffect.getTxPowerLevel());
Log.i("class", "Advertisement start succeeded."+settingsInEffect);
}
});
You need to calibrate your transmission power such that the BLE signal does not transmit further than a metre (or whatever your limit is). Different devices have different hardware with different behaviour so there is no exact transmission power which will transmit in a 1 m range if it was set for any BLE device. Also, the RSSI is a measured value which must vary as the distance between the transmitter and receiver is varied. The RSSI value that is set is a value used by other devices that sense the beacon, to calibrate the calculations those devices do which involve the beacon. For example, you could set the RSSI to a value which is the approximate measured RSSI when the beacon is 1 m away from the receiver. This could assist with the calculation of distance from the beacon when sensing the beacon with different receivers.
Related
I was tring to get the battery level and RSSI value along with distance in mtr of iBeacon acting as server and ESP32 acting as aclient which can collect data from surrounding iBeacons.
I tried doing like finding the rssi values for surrounding ble devices. But i also want to get the battery level of the perticular beacon im intrested in.
I read a paper discussing about a method to reduce beacon's measurement error up to 10%.
I was wondering if it's possible. Basically the self-correcting beacon system is composed of two beacons: target beacon and self-correcting beacon. These two beacons are positioned one meter far from the other.The measuring device (the device we want to calculate the distance from) is positioned at d meters far from the target beacon. Basically the target beacon broadcasts a message, self-correcting beacon will get, calculate the RSSI save as srcPower (RSSI at 1m distance) and broadcasts again. On the other hand, the target device will get the message from target beacon that was sent in the beginning and a message from the self-correcting beacon. So the measuring device uses this "more recent RSSI(d0) (srcPower) to calculate the distance"... does anybody tried to implement and it worked?
The link to the scientific paper is this one:
https://www.ronpub.com/OJIOT_2015v1i2n03_Cho.pdf
I would like to make my Arduino+HM-10 detect Estimote beacon distance without using phone connection but I’m not sure it’s even possible.
Can I detect the beacon only with HM-10?
Can I estimate the distance between my Arduino+HM-10 and the beacon? I know Apple didn’t publish the algorithm but I have already estimated distance to a beacon with a Cordova app on Android.
Yes, it is possible.
You have to use RSSI and algorithm that you have to choose depending of what you want to achieve.
Please, find my answer here, in order to get more details, especially on BLE technology limitations for distance measurement.
Yes, it is possible and with using a Firmware newer than v538 (you can check your version via the command "AT-VERS?") it is quite easy as well.
SoftwareSerial mySerial(8, 9); // RX, TX
// Connect HM10 Arduino Uno
// Pin 1/TXD Pin 7
// Pin 2/RXD Pin 8
void setup() {
Serial.begin(9600);
mySerial.begin(9600);
}
void loop(){
String message;
if (Serial.available()) {
c = Serial.read();
mySerial.print(c);
}
if (mySerial.available()) {
message = "";
delay(10);
while (mySerial.available()) {
c = mySerial.read();
message = message + c;
}
Serial.println(message);
}
This is the basic code to get a connection with your HM10 [the rx/tx pins might vary]. If you send a "AT" through your serial monitor, the HM10 should give back an "OK" now.
You might need to setup your HM10 as a BLE central device before you can start scanning for Beacons. This is done by sending:
AT-ROLE1 //sets central role
AT-IMME1 //should work without prior activation
AT-RESET //restarts the HM10
After that, if you send "AT-DISI?" through the serial monitor, the HM10 should start looking for iBeacons and (case it finds one) give back the following [the P´s are placeholders]:
OK+DISC[P0:P1:P2:P3:P4]
This message contains the POWER (sending signal power) and RSSI (recieved signal strength) of the iBeacon, from which the distance to the beacon can be deducted.
The last 2 digits of P3 contain the POWER of the iBeacon, P4 is the RSSI value.
[note: the 2 Power digits are hex values, you need to convert them into decimal values first --- the number should be somewhere around 190]
The most common way to measure distance between the Beacon (as far as I know) is:
distance = 10 ^ ((POWER-RSSI) / 10n) [n is between 2 and 4, I use 2]
:) I hope that helps and good luck on your project.
I try to use beacon(HM-10) to broadcast my sensor's data, but there is a problem that I use a loop to write AT commands, after a while, it doesn't respond anything.
Here is the part of the code:
String pre = "AT+MARJ0x";
int sensorData = 0;
loop () {
sensorData = getSensorData(); // always returns 100 ~180
String atCommand = pre + sensorData; // ex: AT+MARJ0x100
BTSerial.print (atCommand);
delay (200);
}
It initially work successfully about 3-mins, and then it doesn't work and can't be sent any at commands.
Can anybody help me fix this problem?
What you are trying is not possible with an Ibeacon.
All you do is set-up the major number of Ibeacon data in your HM-10device over and over again with sensor data.
major number is a part of the Ibeacon data spec:
(source: https://developer.mbed.org/blog/entry/BLE-Beacons-URIBeacon-AltBeacons-iBeacon/)
Data Spec:
IBeacons broadcast four pieces of information:
A UUID that identifies the beacon.
A Major number identifying a subset of beacons within a large group.
A Minor number identifying a specific beacon.
A TX power level in 2's compliment, indicating the signal strength one meter from the device.
This number must be calibrated for each device by the user or manufacturer.
A scanning application reads the UUID, major number and minor number and references them against a database
to get information about the beacon;
the beacon itself carries no descriptive information - it requires this external database to be useful.
The TX power field is used with the measured signal strength to determine how far away the beacon is from the smart phone.
Please note that TxPower must be calibrated on a beacon-by-beacon basis by the user to be accurate.
For a HM-10 device AT-commands are normally only used to set-up the device, not for sending data.
Google some examples and learn how to setup communication between BLE devices.
I'm building a system using two ultrasonic sensors and sending data through Xbee. I'm using two nodes in AT end point, one coordinator in AT mode as well.
For testing I've used the basic Arduino example:
if(Serial.available > 0) {
incomingByte = Serial.read();
if(incomingByte == 'H') {
//DO SOMETHING
}
}
It works fine for byte coming from 1 node.
How can I implement to check if incomingByte is receiving data from node1 and node2 at the same time?
you can't. Serial is born to be used by only two pair, infact it sdoes not have data collision managment (that mean if the sensor write toghedere, you will get ureadable data).
you can see the xbee as a serial, but that has collision detection and resolve under the hood. So you can't have parallel message.
You can add to the packet the time of the reading, and usa that
Also you can't use two ultrasonic togheder without taking big precautions as they will affect each others.