Hello,

I am able to send up to 5 sensors (PID´s) from my Arduino to the app. I can compile succesfully the scketch with up to 20 sensors, but my HC-05 bluetooth module, can´t stablish comunication with torque, after adding the sixth.

Clue: If i name the 5 PID´s with a very short name (three characters), i can stablish comunication. on the other hand, if i use a long name, it only allows me to send 4 PID´s.

symptom: The “bluetooth” icon turns to orange color and a message of (no OBD comunication pops up).

My string declaration below:

const String sensors[SENSORSSIZE] = {
“0”, DIGITAL, IS_INPUT, “-“, “RPM”, “Og0”, “x1”, “0”, “1”, //Pin A0 (23 físico)
“1”, DIGITAL, IS_INPUT, “-“, “MAP”, “Og1”, “Kpa”, “0”, “1”, //Pin A1 (24 físico)
“2”, DIGITAL, IS_INPUT, “-“, “ECT”, “Og2”, “C”, “0”, “1”, //Pin A2 (25 físico)
“3”, DIGITAL, IS_INPUT, “-“, “IAT”, “Og3”, “C”, “0”, “1”, //Pin A1 (24 físico)
“4”, DIGITAL, IS_INPUT, “-“, “O2”, “Og4”, “v”, “0”, “1”,
/*
“5”, DIGITAL, IS_INPUT, “-“, “RPT”, “Og5”, “”, “0”, “1”, //Pin A0 (23 físico)
“6”, DIGITAL, IS_INPUT, “-“, “DOL”, “Og6”, “”, “0”, “1”, //Pin A4 (27 físico)
“7”, DIGITAL, IS_INPUT, “-“, “DOC”, “Og7”, “”, “0”, “1”, //Pin A0 (23 físico)
“8”, DIGITAL, IS_INPUT, “-“, “PW”, “Og8”, “”, “0”, “1”, //Pin A5 (28 físico)
“9”, DIGITAL, IS_INPUT, “-“, “STP”, “Og9”, “”, “0”, “1”, //Pin 0 (2 físico)

“6”, DIGITAL, IS_OUTPUT, “0”, “K”, “K”, “bit”, “0”, “1”, //Pin 1 (3 físico)
“7”, DIGITAL, IS_OUTPUT, “0”, “L”, “L”, “bit”, “0”, “1”, //Pin 2 (4 físico)
“8”, DIGITAL, IS_OUTPUT, “0”, “M”, “M”, “bit”, “0”, “1”, //Pin 3 (5 físico)
“9”, DIGITAL, IS_OUTPUT, “0”, “N”, “N”, “bit”, “0”, “1”, //Pin 4 (6 físico)
*/ };

i don’t know the specific about this project

but i did a little obdii sniffer project in the past

in my case a was blowing up the memory of the arduino i suspect

so you have to be carefull in your variable declaration and number use to use the minimum possible

don’t know if you find the issue

one way you can downsize the variable

instead of declaring all the sensor in one shot …

if possible declare each sensor one after the other in a for loop or something to reduce the amount of data into memory

was aloo wondering if there is a caracter limit in string probably wayyyyy long lol

Hi guys, I`m sorry for delay in response.

I tried what you suggested with no sucess.

I am attaching the scketch in order to please you help me by trying at your side.

The main differences with Ian scketch are:
*I am using hardware serial, instead of software serial (I also tried with software serial with no sucess).
*I am not reading directly the pin. I am taking an average value and then sending it to torque (see “get sensors”, id ==3)
*I am receiving all values (except id = 3) from other micro through I2C.

The scketch was proved before paste it in here. If i just change sensorsize from 9*5 to 9*6 and include the sixth sensor in string declaration, it compiles but wont work.

Thanks in advance.

Edit: Is not allowing me to post it complete.
My email: guafa678@gmail.com

don’t know if it will help

String doesn’t seem to work well with arduino

Char seem’s to be the safer option for some reason

const string should use less ram but, that way out of my programming skills

passed a couple of hours reading into this … and it can get very complexe rapidly

just for fun on what are you using this project on ???

personnaly i did a small project on a car … i just inserted some sensor into the can bus itself

i used the arduino to answer instead of the car for the boost sensor output that was higher than the 255 kpa max in the standard

but finaly found the correct pid so the arduino was removed

Hi guys, we´ve made it!!!

I could send more than 15 PID`s in my cheap atmega328p and using only something about 3% of SRAM memory (instaed of 50%).

I had to change significantly the scketch. Basically i eliminated PID´s string declarations and Inserted them “manually” in “sensor definition” function.

Thank you all guys for your time and support.

P.S. email me if i can help someone about this topic (Arduino/atmega328p).
email: guafa678@gmail.com