[[computemodul4_temperature_test]]

Hardware

PI Compute Board:

Board:

WIFI Board:

Measurement devices

  • PI4 Internal CPU Thermometer
  • Multimeter: AM-550-EU PTC Temperature for Wifi Temperature Measurements
    • The temperature of the wifi module by placing the ptc at the heatsink of the wifi module
    • Not highly accurate, but should give a indication

Lab Power source

  • Quatpower LN-3003

Software

no bluetooth

  • config.txt
  • dtoverlay=disable-bt

no wifi

  • config.txt
  • dtoverlay=disable-wifi

no eth

reduce cpu freq

  • config.txt
  • arm_freq=500
  • arm_freq_min=200
  • arm_freq_max=1000

leds

  • config.txt
  • dtparam=act_led_trigger=none
  • dtparam=act_led_activelow=off
  • dtparam=pwr_led_trigger=none
  • dtparam=pwr_led_activelow=off

no audio

  • config.txt
  • dtparam=audio=off

no USB

Camerasoftware

pi@testi:~$ cat test_dual_cam.py 
import time
from datetime import datetime

import picamera
c0 = picamera.PiCamera(camera_num=0)
c0.resolution = (3280,2464)
c0.exposure_mode = "beach"
c1 = picamera.PiCamera(camera_num=1)
c1.resolution = (3280,2464)
c1.exposure_mode = "beach"

while True:
    pic_stamp = datetime.now()
    filename = pic_stamp.strftime("%Y-%m-%dT%H-%M-%S.%f") + "_a" + ".jpg"
        
    start = time.time()
    c0.capture(filename, format='jpeg', quality=95, thumbnail=None, use_video_port=False)
    end = time.time()
    duration = end-start
    print("[Photo0] image capture took [s]:{0:8.3f}".format(duration))

    filename = pic_stamp.strftime("%Y-%m-%dT%H-%M-%S.%f") + "_b" + ".jpg"
    start = time.time()
    c1.capture(filename, format='jpeg', quality=95, thumbnail=None, use_video_port=False)
    end = time.time()
    duration = end-start
    print("[Photo1] image capture took [s]:{0:8.3f}".format(duration))
    

WifiSoftware

cat /dev/zero  | sudo ./tx wlan0 

Tests

Testmode Time (h) Power usage (Wh) Power usage (W) CPU Temp (°C)
IDLE 0:00 2.488 1.095 38
use 2 cameras 0:00 2.489 1.8 39
use 2 cameras 0:15 2.95 1.8 43.8
use 2 cameras 0:30 3.4 1.8 44.3

Using the power usage in Wh a mean power of ~1.8W is needed when using 2 cameras.

Testmode Time (h) Power usage (Wh) Power usage (W) CPU Temp (°C) WIFI Temp (°C)
IDLE 0:00 - 1.7 43.8 30
use 2 cameras 0:00 - 2.4 43.8 30
WIFI 0:00 - 2.65 43.8 30
use 2 cameras + WIFI 0:00 4.83 3.2 43.8 30
use 2 cameras + WIFI 0:15 5.666 3.2 52.0 48
use 2 cameras + WIFI 0:30 6.52 3.2 53.0 50

Using the power usage in Wh a mean power of ~3.38W is needed when using 2 cameras + wifibroadcast.

As it turned out that the radio power amplifier was not connected in test #2, i reran the test. Power is provided by the laboratory power source @ 12.3V + DCDC Converter @ 5V for the cm4 board.

NOTE: The sligtly incread Idle power usage is due to the additional DCDC converter, and the powermeasurement BEFORE this converter.

Testmode Time (h) Power usage (W) CPU Temp (°C) WIFI Temp (°C)
IDLE 0:00 2.3 34.5 27
WIFI 0:01 5.78 36.5 29
WIFI 0:11 5.78 46.7 58
WIFI 0:21 5.78 51.0 62
WIFI 0:30 5.78 51.0 63
  • computemodul4_temperature_test.txt
  • Last modified: 2021/05/17 01:00
  • by wf68spef