Central.m

- (void)centralManager:(CBCentralManager *)central
 didDiscoverPeripheral:(CBPeripheral *)peripheral
     advertisementData:(NSDictionary *)advertisementData
                  RSSI:(NSNumber *)RSSI {
    if ([self isIgnorePeripheral:RSSI]) {
        return;
    }

    if (peripheral) {
        if (![self.peripherals containsObject:peripheral]) {
            [self.peripherals addObject:peripheral];
        }

        [self.centralManager connectPeripheral:peripheral options:nil];
    }
}

- (BOOL)isIgnorePeripheral:(NSNumber *)RSSI {
    // Received Signal Strength Indicator
    if (RSSI.integerValue > -15) {
        return YES;
    }

    if (RSSI.integerValue < -60) {
        return YES;
    }

    return NO;
}