Powering Openmv H7 from 3.7V Lipo Battery (Headless)

OpenMV Products
1

Hello,

How do I check that I am powering “ON” the Openmv H7 from a 3.7V LiPo (headless mode I guess)?

Essentially, I want to run the H7 as a headless Thermal Cam streamer.

Picture below; I have the LiPo (integrated to a TP4056 charging module) connected to the H7 female JST → to male JST connector, but I am seeing no indication of the H7 powered on. Thanks.

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2

Never mind, I had the polarities for the connector backwards. I think I dodged a bullet as well, as I didn’t fry the board (no magic smoke, thank goodness). That said, on headless mode the blue Led lights on constantly (not sure what that means). Which brings me to my next question; how would I go about running my python code when I power on the H7 using the LiPo? Sorry, as you can tell, I’m fairly new at python embedded systems/microcontrollers. Thanks!

3

Hi, just save the script as main.py (Tools-> save open script as main.py) and it will run on boot.

4

Got it, works. thank you!

5

I have connected a 3.7 V LiPo battery, but get no lights or indication my H7 R2 is receiving power:

IMG_20220823_171932_HDR
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6

The light is controlled by what scrip the board is running. If you didn’t blink the light in the script it will not turn on.

7

Just to confirm, then, that if operated in “headless mode”, it is not like when I connect it via USB to my computer and the light flashes indicating power/connection.

8

The light is being flashed by the default script on the camera. Once you deploy a new script the camera does whatever the new script does.

9

Are there specific battery specs other than 3.7 V LiPo? I have loaded the following as main.py:

import time, pyb

while (True):
    led = pyb.LED(1)
    led.on()
    time.sleep_ms(150)
    led.off()
    led = pyb.LED(2)
    led.on()
    time.sleep_ms(150)
    led.off()
    led = pyb.LED(3)
    led.on()
    time.sleep_ms(150)
    led.off()

When I connect the USB cable, the lights flash as expected. When I plug the battery in, I don’t get any flashing lights.

10

Huh, yeah, a 3.7V lipo should definitely work. I have a few cameras myself powered this way. Is the battery charged and not dead? Do you have a known good battery?

You need at least 3.5V on the battery.

11

I am thinking it is the battery. I bought it new and charged it up. But that doesn’t mean anything. I just wanted to check if someone else agreed that it is likely a bad battery. Thanks.

12

I have a question on that. I assume that the male connector on the H7 is S2B-PH-K-S produced by JST. Do you remember which female connector you used for connecting the LiPo to the H7 device?