Heart rate sensor MAX30102

[richard]

The breadboarding....i think is clear as schematic, if you like schematic i could also make one

not really , i looked at 3 modules the mikroe one is 3.3v only .the one mouser/e14 sell is 3.3 or 5v and has a logic level converter on board
another provides no schematic and only vague spec no schema, i cannot identify your module

by the look of your cro traces you are belting 5v in on the scl,sda pins , better hope its 5v tolerant

TRISC = %10000100 ' portc.7 and portc.2 set as input.

is wrong both must be input , the routine will switch tris as req
if the module have 3.3 v pull ups might be better to use the open collector/drain method for i2c command
[edit] forget that ,its open collecter by default.

all other unused ports are configured as output and set to low.

unnecessary

SDA var portc.1
SCL var portc.2

conflicts with your tris statement anyway

Now regarding the FIFO_WR_PTR it is not clear to me in the manual what data to write to it.

me either but it will do something if everything else is correct

[astanapane]

Changed to input both portc.1 and portc.2

This is the module.

https://reedpaper.wordpress.com/2018...x-wrong-board/

I have also following the "fix". Well module is 3.3V but i have never seen in all of the Arduino connections any note.

I have changed the connections and used the 3.3V output from the Display to power the rest of the circuit.

I dont beleive that i have burned the module as this is the result before i change the voltage supply from 5V to 3.3V.

i2cwrite sda,scl,$AE,$04
pause 100

This is the proof of ACK in 9th bit. As from the data sheet if the Id is the right one, the module pulls down the SDA during 9th bit to acknowledge receipt of data.

[richard]

i2cwrite sda,scl,$AE,$04

i see you're still torturing the device sending incomplete write resister i2c control messages at it

[astanapane]

yes i havent send any data yet as i'm searching in the i2c how to do that corresponds to the max30102 manual.

At least i know sensor is responded by pulling SDA down on 9th bit. This is something for me.

[astanapane]

i've done many tries. I just want to see if the red LED inside the sensor is alive. At least by sending a command to activate it.

This is as from the pseudo code the first step. I really do not know if that is the right way to send Device ID + write mode
Then send the FIFO_WR_PTR (i still dont know what are the bits needs to be configured)
REPEAT START

addr = $04   ; FIFO WRITE POINTER REG ADDR IS 0X04
i2cwrite  SDA,scl,contwr
i2cwrite  SDA,scl,contwr,addr
i2cwrite  SDA,scl,contwr
i2cwrite  SDA,scl,contwr,addr

Apart from pseudo code in the datasheet, Next i tried to send mode for the heart rate mode only

addr = $09   ' mode configuration 
i2cwrite  SDA,scl,contwr,addr,[modled],error ' ModLED = $02 as per data sheet heart rate mode only

In the end i tried to send the led pulse amplitute. 

addr = $0C   ' led pulse amplitute
i2cwrite  SDA,scl,contwr,addr,[led1_pa],error' LED1_PA = $3F  , 12.6 mA

no luck......keep walking.

[richard]

given that you can buy these for < $20us delivered to your door i doubt its worth while making them other than as an intellectual exercise
https://au.banggood.com/BOXYM-oFit-2...r_warehouse=CN
i have tried the sparkfun arduino demos and was not particularly impressed with accuracy or stability of readings obtained
{maybe my heart is inaccurate and unstable}
the raspberrypi code goes about it quite differently&nbsp; with some dsp done on data collected in a fixed sampling period [not tried it].
i have no experience with these things , i don't know if reverse engineering the arduino code is even worthwhile
but no matter how you go about it the sort of digital signal processing needed will be lots and lots of hard work with pbp
do you have a plan ? have you established optimal device settings to get the best readings ? how much data is needed and from where ?
reading and writing to the device is child's play, setting it up to get meaningful data and being able to extract information from that data is another story

[Ioannis]

I double what Richard pointed.

Ioannis