Can LoRa module damage my periferal?

Projects General Guidance
1

I've been working with Lora module 915 MHZ RFM95, so i get the data every second, and transmit it via LoRa every 10 seconds, some source said Lora is not suitable for high data rate so i think sent the data every second gonna mess it up and make it work harder, my problem is every time the lora send the data (every that 10 seconds) my periferals (mpu-6050 and lcd) blinking once, it happen less than a second but my eyes can caught it, is it safe? lora draws high current in transmission process but how to overcome this so it doesn't affect my readings data gradually? i'm scare that my periferal gonna be slowly damage after operates several times.

should i use another power source for lora? since it's sharing the same voltage 3.3v with my mpu-6050 (my lcd use 5v) from esp32 3.3v pin, my issue is i'm gonna use battery as power supply, what recomendation for the power supply for my esp32? this far my idea is using hw 553 boost converter dc to dc from 0.1-4 V to 5 V, but last time when my battery li-ion drop to 2 V it can't provide enough voltage to power my lcd, i can't use power adapter + IC 7805 since my project supposes to be outdoor.

image
image376×375 30.1 KB
HW 553

should this hw 553 module supposed to be pricy? cause mine, i bought from the store with cheap price, any recommendation what boost converter alternative that i can used?

image
image818×644 62.1 KB

sorry for the mess schematic diagram, u can tell i'm a newbie :slight_smile: (and also there's another problem with output and battery load sharing with tp4056 module but i'm gonna talk about it in another topic

2

There's no Vcc on the mpu6050.

3

If you let li-ion battery voltage to drop to 2V, you are risking much more than "gradually damaging periferals". You damage the battery and it's becoming dangerous.
You need a battery management/protection to start with.
Some Esp32 boards have battery management on-board, might want to consider them.

4

If you set up the LoRa device for max power, 20dBm\100mW, then yes it can consume 100mA or more.

So set the transmit power to minimum, 2dBm, and the current used should drop quite a bit. If the distance\range is not too far it should work OK at low power, try it.

A simple packet of 8 bytes can take as little as 8.5mS to send, is that a high enough data rate ?

5

sorry, i use the wrong name, it's gy-521 module who has mpu6050 on it, i also confuse when look the datasheet, and most people call it mpu6050, even in some research article they call it mpu-6050 even actually they use gy-521 :))))

6

i saw there's some version of advance dev boards for "already esp32 devkit" like the one on the left side

image
image597×590 73 KB

i use esp32 devkit v4 on the right side, do u mean "Esp32 boards have battery management on-board" is the one on the left side?

7

No diffrence, it needs Vcc.

8

ouh if it's that what u mean, i change the i2c address from 0x68 to 0x69, so i should set the AD0 high, cause it has same addres with rtc-ds3231 module

9

No, I mean Esp32 dev boards that have integrated battery management.
Like this:

There are probably hundred different boards with battery management available nowadays. Smallest one afaik is XIAO ESP32C3
Some have even 18650 battery holder on board like Wemos Esp32.

10

No.

11

This is what @Railroader mean:

bild
bild213×130 19.6 KB

12

oh yeah, I've seen it before, but it's hard to find in my country, and I don't have enough to order imports :slight_smile:

13

sorry that i still don't get it @Railroader @ledsyn

do u guys mean i should also connect the vcc while ad0 high? in some source the vcc must be doesn't connect to anything, i test it before, and my mpu works fine as ad0 works as the vcc

14

i still figure it out how to set the lora power based on LoRa.cpp and Lora.h file, i use LoRa library by sandeep mistry and also see the datasheet of RFM95 Microsoft Word - RFM95_96_97_98W.doc

image
image777×403 26.7 KB

the default transmit power of this module is 13 dBm with minimum -1 dBm and maximum 14 dBm, i declare the variable int level = 2, is this right?
image

15

well, this is what my packet looks like

void sendReadings() {
  message = String(readingTime.hour()) + ":" + String(readingTime.minute()) + ":" + String(readingTime.second()) +
            "/" + String(tempd) + "&" + String(hum) + 
            "&" + String(ax_gal) + "," + String(ay_gal) + "," + String(az_gal) + String(classifyPGA(r_gal));
  LoRa.beginPacket();
  LoRa.print(message);
  LoRa.endPacket();
  Serial.println("Counter: " + String(counter) + " | Sent: " + message);
}
16

Yes. AD0 is a logic address pin, not a power pin. You are phantom powering the device. Some circuits get damaged or destroyd that way.

17

Time for a Google? "Vcc GND"

18

The default transmit power that the LoRa Library you are using is 2dBm to 20dBm.

19

Well if you want to know the 'data rate' yoiu need to work out how long the packet is, in bytes.

A lot of people would suggest you avoid using Strings on Arduinos.

20

oh my god, i didn't realize that, i thought the vcc being replaced with ad0, thank u so much sir for ur help