Hello, I am trying to get data from a digital blood pressure monitor. I am using this video as a reference How to Make Arduino Blood pressure monitor device | DIY Arduino Blood Pressure Monitor. Below is my blood pressure monitor device, and the EEPROM is C358ABK97Z. I am using a SOIC-8 clip to connect the EEPROM with the ESP8266.
blue wire (GND->GND)
red wire (SDA->D2)
yellow wire (SCL->D1)
I use the code that was given in the video, but I cannot get the data, and I also tried a few kinds of code given by AI, but I still cannot get the data. I can't find the datasheet of the C358ABK97Z. I'm a newbie in this field, and I don't know why I can't get the data. Is the problem of SOIC-8 clip didn't contact firmly with the EEPROM? But I think they have already attached well, or is the problem of the EEPROM is cannot be hacked? Can someone give me some help?
That may be because the chip you are attaching your clip to might not actually be a memory chip, although without a data-sheet it is difficult to be sure about anything. I believe that the two numbers on the chip are meant to be separate, but I can't find anything for C358A either, nor for the manufacturer logo on the chip. A '358' often denotes an OP amp, but that seems doubtful as well. The 3 pins marked with the white silkscreen suggests that they might be tied together but its difficult to tell just from the photo, but easy enough to check with a multimeter. it might possibly be a motor driver IC.
BTW, are there any ICs on the opposite side of the board?
Do you have a oscilloscope or logic analyzer to see the signals on the pins?
That is the first step.
(and beware, hacking any device is often not trivial, even for experienced people)
Why not use the USB port?
I can get all the data I need from my monitor from the USB connection.
There are no other ICs on the opposite side of the board
Unfortunately, I have no oscilloscope or logic analyzer.
noted, thanks for your advice
It is a cheap blood pressure monitor, I think it is only for power supply, my monitor does not have any response when I connect with the USB port
Please post a pic of the back of the board. There will probably be a black blob with a microprocessor underneath.
You probably need to look in the manual for instructions on how to use the USB port. Mine transmits with Bluetooth so I can't help.
How will you be able to determine which connection has “data”?
If you have a spare Arduino you can make your own simple logic analyzer, and put the output in the Serial plotter, or write to an SD card so you can view the data in spreadsheet.
It will not be perfect but it could show if there is data on a line. Code could look like this.
//
// FILE: logicAnalyzer.ino
// AUTHOR: Rob Tillaart
// VERSION: 0.1.0
// PURPOSE: Very simple Arduino logicAnalyzer
// DATE: 2025-10-20
// URL:
//
void setup()
{
Serial.begin(500000);
Serial.println(__FILE__);
pinMode(8, INPUT);
pinMode(9, INPUT);
pinMode(10, INPUT);
pinMode(11, INPUT);
pinMode(13, OUTPUT); // use built in LED as indicator
}
void loop()
{
int a = digitalRead(8) * 16 + 0;
int b = digitalRead(9) * 16 + 32;
int c = digitalRead(10) * 16 + 64;
int d = digitalRead(11) * 16 + 96;
Serial.print(a);
Serial.print('\t');
Serial.print(b);
Serial.print('\t');
Serial.print(c);
Serial.print('\t');
Serial.print(d);
Serial.print('\n');
}
// -- END OF FILE --
From there you could expand the functionality of the logic analyzer.
- reduce from four to one line to increase sample frequency.
- use low level registers.
- use built in LED as indicator
- increase baudrate
- only sample on a clock pulse
My Omron MIT-10 BP monitor comes with a USB port. Nice and easy, though uses Omron's own software to download it. Can also be exported as CSV file.
Aren't you making a lot of work for yourself? I ran the PCB code (BP-105 etc.) through Google and found nothing. The monitor looks pretty basic. WHO? World Health Organisation?
Possibly, after a lot of work, you could read the EEPROM, but if you like a challenge....
It may not help much but here it is on aliexpress: https://de.aliexpress.com/item/1005006678164302.html
You may find another retailer offering the same product but with more information.
That looks just like a HUAtech HTC358A dual opamp with only one amp being used
NOT an EEPROM
I modify some the code to get text value
void setup() {
Serial.begin(115200);
pinMode(D2, INPUT); // Example: SDA line
pinMode(D1, INPUT); // Example: SCL line
Serial.println("Starting simple logic test...");
}
void loop() {
int sda = digitalRead(D2);
int scl = digitalRead(D1);
Serial.print("SDA: ");
Serial.print(sda);
Serial.print(" | SCL: ");
Serial.println(scl);
delay(2); // small delay to make output readable
}
it print constant 1 when the blood pressure device is off and after the measurement while when it is measuring it show fast flicker of 0 and 1, is that means that the data can be read from the chip?
because i want to control my budget, the price of the omron bp monitor is 6 times more expensive than my current bp monitor
It's NOT an EEPROM.
ouhh that's a bad news, thanks for telling me
I think that other square IC to the right is the microcontroller.
Can you see a part number on it?