Hack Blood pressure monitor

Hello, I want to hack my blood pressure monitor so that can be connected to arduino. I follow this tutorial https://youtu.be/5zRlYQUBFiw . My bp monitor its similar with the bp monitor in this tutorial, just different logo. When I see the pcb of my bp monitor, its little bit different. There is no pin p10 and p12 like the pcb on video (picture 1). I see on my bp monitor pcb, a small thing with 6 pins (picture 4). Its that i2c eeprom? Also, i see 4 pin under left button has pin gnd, dm, dp, vbat. Can I connected this to rx/tx or other pin arduino? How can I hack this bp monitor? Please help me. Thank you

There are a few 6 pin EEPROMs out there, most are 8 pin.

A 6 pin SOT device between two large capacitors is more likley to be a voltage regulator.

Check the device part number and\or measure the voltages on all 6 pins.

Can you take a picture where the marking on the chip can be read? Also the big one. Maybe we can identify the chip and check the datasheet. Maybe this device has a EEPROM build in. The small 6-pin device is unnecessary far away from the main chip.

Just in case, can you confirm the monitor can remember the values after the battery has been remove for a little while. It might simply store the values in some small low power RAM area. There are chips with a backup memory area that can be used while in ultra low power mode.

Here the chip

The chip code is AC20CM2C0M.1-1A4.
And yeah, the monitor can save the value of measurement when I remove the battery. Please help me sir, thank you

It looks like the company could be Zhu Hai JieLi Technology


They do not have a secure site (https) and the site is in Chinese only. They sell all kind of chip sets including blood pressure monitoring. They have large flash memory versions, so they could be using parts of it for saving data as well. But, that is speculation because I do not read Chinese.

Did you identify the small chip?

I don't get the datasheet, but sir, I already try to connect 4 pin under left button(picture 4) to arduino
Gnd - gnd
DM - rx
DP - tx
Vbat - 3.3v

The bp monitor work when I connect the gnd and vbat without battery but didnt work when i connect all
How can I receive data from bp monitor to arduino?
Or maybe I need extra hardware like usb host shield? The 4 pin its seen like usb cable. Can I do it? Thank you

Sorry, I am not a hacker, and the microcontroller might not send out any data except to the LCD. And that seems to be directly driven. Direct LCD signal are not easy to read with a digital read. So, there might not be any easy-to-read data available.

Without knowing what is going on you will not be able to crack this. And a USB shield will not help.

The best option is to use an oscilloscope to look at all the signals.

Most signal will be obvious e.g., LCDs, clock, Vcc and GND and the buttons. That should only leave a few pins that need some thinking. :slight_smile:

I have a similar monitor with what seems the identical chip - the connection it has is not an USB connection at all but a 115200 baud serial connection. The device sends out some debug data during operation so it is I think possible to grab the blood pressure from that.

For instance this is what it sends when pressing the memory button:

read Rec result:1
 sys = 129
 dia = 85
 pulse = 80
 mean = 0
 heat = 0
record_time:2020-01-01 10:00:40

How can you connect it to arduino? Can you explain the wiring? Thankyou

Depends on what you want to do and what aduino you got - If you just want to view the data incoming you can just connect GND to GND, TX to TX and RX to RX on the Arduino. after that you can open the serial monitor in the arduino IDE at 115200 baud and see the data.

if you want to do anything with the data on the Arduino you need to cross RX and TX - ie connect RX on the monitor to TX on the Arduino and vice versa. After that you can Work with the data in the code you upload.