Hello my fellow arduino enthusiasts,
Ive just started using these miraculous machines and love everything so far.
I have a project, in which a arduino nano ble sense reads out its 8 analog inputs, its temperature sensor and its acceleration sensors, than writes them each to a characteristic.
A pi 3 b then accesses those on a regular basis and writes them to a .txt
After some time (inconsistent, one time after 14 minues, on time after 17, one time after 15 …), the arduino refuses connecting and the orange LED starts flashing 3 times slow, 5 times fast, on repeat.
I am new to all of this and maybe I made a mistake by trying jumping from making an LED flash to sensor data BLE transmission 
but since this is important for my studies, I would extremely appreciate any help.
Here is one version of my code on the arduino (i cut out some stuff due to character restrictions of the board):
#include <ArduinoBLE.h>
#include <Arduino_HTS221.h>
#include <Arduino_LSM9DS1.h>
BLEService guardService("1101");
BLEIntCharacteristic t0("2100", BLERead | BLENotify);
.
.
.
BLEIntCharacteristic t6("2106", BLERead | BLENotify);
BLEIntCharacteristic t7("2107", BLERead | BLENotify);
BLEIntCharacteristic ta("2108", BLERead | BLENotify);
BLEIntCharacteristic ax("2109", BLERead | BLENotify);
BLEIntCharacteristic ay("2110", BLERead | BLENotify);
BLEIntCharacteristic az("2111", BLERead | BLENotify);
//int m = 0;
//float xxx=0.0;
//float yyy=0.0;
//float zzz=0.0;
void setup() {
//#Serial.begin(9600);
//#while (!Serial);
//#pinMode(LED_BUILTIN, OUTPUT);
if (!BLE.begin())
{
//#Serial.println("starting BLE failed!");
while (1);
}
BLE.setLocalName("guArdian");
BLE.setAdvertisedService(guardService);
guardService.addCharacteristic(t0);
.
.
.
guardService.addCharacteristic(t7);
guardService.addCharacteristic(ta);
guardService.addCharacteristic(ax);
guardService.addCharacteristic(ay);
guardService.addCharacteristic(az);
BLE.addService(guardService);
BLE.advertise();
//#Serial.println("Bluetooth device active, waiting for connections...");
}
void loop()
{
BLEDevice central = BLE.central();
if (central)
{
//#Serial.print("Connected to central: ");
//#Serial.println(central.address());
digitalWrite(LED_BUILTIN, HIGH);
while (central.connected()) {
int battery = analogRead(A0);
//int batteryLevel = map(battery, 0, 1023, 0, 100);
int vt0 = analogRead(A0);
.
.
.
int vt7 = analogRead(A7);
HTS.begin();
int vta= HTS.readTemperature(CELSIUS);
//# Serial.print("Battery Level % is now: ");
//# Serial.print(vt0);
//# Serial.println(vt1);
t0.writeValue(vt0);
//t1-t6 same way, cut out due to character restrictions of the board
t7.writeValue(vt7);
ta.writeValue(vta);
// IMU.begin();
// float x, y, z;
// float x0 = 0;
// float y0 = 0;
// float z0 = 0;
// int n = 0;
// while (n < 5) {
// if (IMU.accelerationAvailable()) {
// IMU.readAcceleration(x, y, z);
// if (abs(x)>abs(x0)) {
// x0=abs(x);
// }
// if (abs(y)>abs(y0)) {
// y0=abs(y);
// }
// if (abs(z)>abs(z0)) {
// z0=abs(z);
// }
// delay(100);
// n = n+1;
// }
// }
// IMU.end();
//
//
// m=m+1;
// if (m>20){
// m=0;
// xxx=0.0;
// yyy=0.0;
// zzz=0.0;
// }else{
// m=m+1;
// if (abs(x0)>abs(xxx)) {
// xxx=abs(x0);
// }
// if (abs(y0)>abs(yyy)) {
// yyy=abs(y0);
// }
// if (abs(z0)>abs(zzz)) {
// zzz=abs(z0);
// }
// }
// int vax = (int) (xxx*100);
// int vay = (int) (yyy*100);
// int vaz = (int) (zzz*100);
ax.writeValue(0);
ay.writeValue(0);
az.writeValue(0);
delay(2000);
}
}
digitalWrite(LED_BUILTIN, LOW);
//# Serial.print("Disconnected from central: ");
//# Serial.println(central.address());
}
And here is the python code on the pi, which was shamelessly stolen from the hexiwear guide and adapted for my needs. It is run on a 10 second basis via cronjobmanagerthingy:
#! /usr/bin/python3
import pexpect
import time
import sys
import os
import binascii
# ---------------------------------------------------------------------
# transforms the crazy hex bits to a normal number (int)
# ---------------------------------------------------------------------
def hexStrToInt(hexstr):
#val = int(hexstr[0:2],16) + (int(hexstr[3:5],16)<<8)
#val = int(hexstr[0:2],16) + int(hexstr[3:5],16) + int(hexstr[6:8],16) + int(hexstr[9:11],16)
#if ((val&0x8000)==0x8000): # treat signed 16bits
# val = -((val^0xffff)+1)
val = int(str(int(bin(int(hexstr[3:5]))[2:])*(100000000)),2) + int(hexstr[0:2],16)
return val
# ---------------------------------------------------------------------
DEVICE = "F5:A5:37:66:E9:A2" # Arduino Mac Adress
if len(sys.argv) == 2:
DEVICE = str(sys.argv[1])
# Run gatttool interactively.
child = pexpect.spawn("gatttool -I")
# Connect to the device.
print("Connecting to:"),
print(DEVICE)
NOF_REMAINING_RETRY = 3
while True:
try:
child.sendline("connect {0}".format(DEVICE))
child.expect("Connection successful", timeout=5)
except pexpect.TIMEOUT:
NOF_REMAINING_RETRY = NOF_REMAINING_RETRY-1
if (NOF_REMAINING_RETRY>0):
print ("timeout, retry...")
continue
else:
print ("timeout, giving up.")
break
else:
print("Connected!")
break
if NOF_REMAINING_RETRY>0:
unixTime = int(time.time())
unixTime += 60*60 # GMT+1
unixTime += 60*60 # added daylight saving time of one hour
# open file
file = open("ledger.txt", "a")
if (os.path.getsize("ledger.txt")==0):
file.write("Device;Time;T0;T1;T2;T3;T4;T5;T6;T7;TA;AX;AY;AZ\n")
file.write(DEVICE)
file.write(";")
file.write(str(unixTime)) # Unix timestamp in seconds
file.write(";")
# # App mode
# child.sendline("char-read-hnd 0x6d")
# child.expect("Characteristic value/descriptor: ", timeout=5)
# child.expect("\r\n", timeout=5)
# print("AppMode: "),
# print(child.before),
# print(str(int(child.before[0:2],16)))
# file.write(str(int(child.before[0:2],16)))
# file.write("\t")
# T0
child.sendline("char-read-uuid 00002100-0000-1000-8000-00805f9b34fb")
child.expect("handle: 0x000b value: ", timeout=5)
child.expect("\r\n", timeout=5)
print("T0: " + str(hexStrToInt(child.before)))
file.write(str(hexStrToInt(child.before)))
file.write(";")
file.write(";")
# ...T1 - T7 i cut out now due to character restrictions of the board here
# # T7
child.sendline("char-read-uuid 00002107-0000-1000-8000-00805f9b34fb")
child.expect("handle: 0x0020 value: ", timeout=5)
child.expect("\r\n", timeout=5)
print("T7: " + str(hexStrToInt(child.before)))
file.write(str(hexStrToInt(child.before)))
file.write(";")
#
# # TA
child.sendline("char-read-uuid 00002108-0000-1000-8000-00805f9b34fb")
child.expect("handle: 0x0023 value: ", timeout=5)
child.expect("\r\n", timeout=5)
print("TA: " + str(hexStrToInt(child.before)))
file.write(str(hexStrToInt(child.before)))
file.write(";")
#
# # AX (same way AY and AZ, again cut due to character restrictions)
child.sendline("char-read-uuid 00002109-0000-1000-8000-00805f9b34fb")
child.expect("handle: 0x0026 value: ", timeout=5)
child.expect("\r\n", timeout=5)
print("AX: " + str(hexStrToInt(child.before)))
file.write(str(hexStrToInt(child.before)))
file.write(";")
#
file.close()
print("done!")
child.sendline("disconnect")
sys.exit(0)
else:
print("FAILED!")
sys.exit(-1)
I have tried not disconnecting from it every time from the pi, but same, i have tried not sending as many values, no success, i am at my witts end. HELP me mario!
