XIAO ESP32C3 not powering mr24hpc1 on startup

Trying to get this combination of ESP32C3 and 24GHz mmWave Sensor - Human Static Presence Module Lite (MR24HPC1) to work with Home Assistant as detailed on this page here. However it seems that the only way to boot the mmWave module is to disconect and reconnect the 5v line after booting the ESP32C3. Some suggestions have been made as detailed in the Github discussion here however I believe this should work without this extra complication. Does anybody have any more information about this mmWave module or a more recent firmware that resolves this issue?

You can put the D6 and D7 for D2 and D3, specific operation see Pin Multiplexing on Seeed Studio XIAO ESP32C3 | Seeed Studio Wiki uart1-at-the-same-time


I have the XIAO ESP32S3 and the MR24HPC1 24GHz mmWave Sensor - Human Static Presence Module Lite. The code hangs when running this code example:


#include <sleepbreathingradar.h>

SleepBreathingRadar radar;

void setup()

void loop()
radar.recvRadarBytes(); //Receive radar data and start processing
if (radar.newData == true) { //The data is received and transferred to the new list dataMsg[]
byte dataMsg[radar.dataLen+1] = {0x00};
dataMsg[0] = 0x55; //Add the header frame as the first element of the array
for (byte n = 0; n < radar.dataLen; n++)dataMsg[n+1] = radar.Msg[n]; //Frame-by-frame transfer
radar.newData = false; //A complete set of data frames is saved

//radar.ShowData(dataMsg);                 //Serial port prints a set of received data frames
radar.Bodysign_judgment(dataMsg, 1, 15); //Output of human movement using sign parameters


None of the examples for the MR24HPC1 seem to work. No data is listed on the serial console in Arduino IDE.

All that prints to the serial console is the “Ready” text.

Can you help?
I need this sensor for a project.
Thank you,

Hi Thane, and Welcome !
At first glance I would say No data from Radar. Check your connections and voltage levels of the supply.
You may also maybe want to add some code to alert if no data is received in buffer.
Allot of the Examples here are untested with current board files , LIB’s and wiki examples. Seeed support IS trying to catch up on some items but their overloaded with all the NEW products.
QC on software is NOT a THING as well. The users on here are the smartest you’ll find and the Seeed Hardware is the MOST bang for the buck IMO.
GL :slight_smile: PJ

Hi PJ Glasso

thank you for the welcome, your response and for the information.

I am following (or attempting to follow) this wiki :

24GHz mmWave Human Static Presence Lite | Seeed Studio Wiki

This is the connection diagram that I used from the wiki.

I have verified that 4.85v is at the radar scanner.

Inline image

I am using this example code: MR24HPCB1_parsed_rawdata.ino

When I run the example, this is the output.

12:11:31.787 →

12:11:31.787 → ESP-ROM:esp32s3-20210327

12:11:31.787 → Build:Mar 27 2021

12:11:31.787 → rst:0x15 (USB_UART_CHIP_RESET),boot:0x28 (SPI_FAST_FLASH_BOOT)

12:11:31.787 → Saved PC:0x42021eaa

12:11:31.787 → SPIWP:0xee

12:11:31.787 → mode:DIO, clock div:1

12:11:31.787 → load:0x3fce3808,len:0x3ac

12:11:31.787 → load:0x403c9700,len:0x9b4

12:11:31.787 → load:0x403cc700,len:0x2908

12:11:31.787 → entry 0x403c98bc

12:11:31.880 → Ready

I heard back from the Seeed Studio support team, they are all on a national (China) holiday for a week and indicate that they will look into this issue when they return to the office on October 7th.

BTW. I am enjoying learning and testing the XIAO ESP32S3 board and I will share any code I get working.

I am a developer that started hardware and software development with Motorola 68020 CPU, Unix and C in the 80’s.

Thank you again,


Ah’ Very Good ,
got my start on the Z80 assembly back in the day, Later developed some 68K hardware and a PAL chip to be the glue logic. a 22v10 chip.Love that "DTACK " Those were AWESOME days. but now this stuff is beyond our wildest thoughts , IMU’s, USB, 3D printing. Yoi… LOL
What Version of firmware is on the Sensor, I see they have downloads on wiki, etc.
I also see that sensor can be hooked up to USB to serial interface. You may want to try that to see if the thing is DOA or not? and S1, S2 activity?
something to try while you wait for seeed.

You may want to up the Baud Rate to 115200 , newer firmware defaults to that.
something like:" mySerial.begin(115200);
try that first/
GL :slight_smile: PJ