Hello,

I need some simple suggestions to build a simple circuit capable of feeding 4x ESP32-cam boards. These 4x ESP32-cam will be to setup inside my car.
So, I have 2 options.
Bring the power from the fuses box to some circuit that will be capable of feeding the 4x ESP32-cam or somehow have a battery feeding the same circuit to feed the ESP32-cams.

I think the fuses box have at least 2 different voltage levels available. So, what circuit can I come up with?

 

Normally a car only has 12V at the fuse block unless you have some form of 24V system (something I know is more common outside the US).

I did not look up the exact current draw of the ESP32 cam modules, but this should be able to power them. https://www.amazon.com/Converter-Voltage-Waterproof-Regulator-Step-Down/dp/B07Y2V1F8V?th=1

Although it says "automotive" I would add a TVS diode or something on the input side to deal with load dumps and spikes in the electrical system for extra caution.

 

I guess that we are to somehow be aware of both the voltage and the current requirements for these cameras?
If the cameras require 24 volts DC to operate correctly then the very best advice is to purchase a regulated switch mode "Boost"type power supply with an adequate current rating. allowing at least a ten percent current ability margin of safety. A well regulated supply set for the correct voltage should serve very well.

 

If you take the time to look into ESP32 CAM modules you will find they come with a camera that plugs into them and does not need a separate power supply

 

Well, according to this ocument:
https://loboris.eu/ESP32/ESP32-CAM Product Specification.pdf

It can have a maximum rating of 310mA of current. Times 4x in this case, if for some reason, in any point in time, the 4 ESP32-cams are woking with the flash light turned on a maximum brightness.

If you take the time to look into ESP32 CAM modules you will find they come with a camera that plugs into them and does not need a separate power supply

Yes, I know that. But the whole module needs power from somewhere!

 

Yes, I know that. But the whole module needs power from somewhere!

I didn't mean you...

Anyways if you can find a power supply something like the link from earlier it would be about the easiest way to go about it. It should not draw much more than 1.5 A max from you car (that is assuming a horrible efficiency rating so it should be a lot less).

An easy place to connect to power in this case would be either your radio power or lighter / power port.

 

Hi Psy,
You can buy a plug in support module for the ESP32 Cam that has on onboard regulator and a micro USB connector. Left side image/

E

 

Hi Psy,
You can buy a plug in support module for the ESP32 Cam that has on onboard regulator and a micro USB connector. Left side image/

E
View attachment 315122

Hi @ericgibbs. Long time no see!
Yes, I have also 4 of those because by mistake, I bought the 2 modules 4 times. I was supposed to by one plug in boardd and 4x ESP32-cam, but I bought 4 of both.
Despite the fact that I have USB connectors in the car, I would need 4 of them, and I don't have 4 available, I think I only have one, atm!

 

hi Psy,
If you decided on a linear regulated 5V supply [the ESP32 Cam has a 3.3v onboard regulator] at say 0.31A.
A linear 5V reg would have to dissipate (12Vbty - 5V) = 7V *0.31A= ~ 2 Watts (use a heat sink]

Also, if using the vehicle's battery supply, design the regulator to give protection against surges and spikes on the 12Vbty supply.

E

 

hi Psy,
If you decided on a linear regulated 5V supply [the ESP32 Cam has a 3.3v onboard regulator] at say 0.31A.
A linear 5V reg would have to dissipate (12Vbty - 5V) = 7V *0.31A= ~ 2 Watts (use a heat sink]

Also, if using the vehicle's battery supply, design the regulator to give protection against surges and spikes on the 12Vbty supply.

E

About the protection against surges and spikes, you mean something like a flyback diode?

 

hi, Psy,
A very basic system would be like this image.
Some users add a series choke in the positive input.

E

 

hi, Psy,
A very basic system would be like this image.
Some users add a series choke in the positive input.

E

Hi again.
@ericgibbs a question.
I was starting to build the circuit for the voltage regulator.
Datasheet for 7805 says if the regulator is far from the voltage source, we should include a capacitor from te regulator input to GND.

If I add your circuit protection suggestion, I'll end up with 2 capacitors in parallel. Is this supposed to happen or I will use the capacitor of your suggestion protection circuit as the one to also use in the 7805 input?
Something like this:


And is D3 needed?

 

Hi Psy,
D3 protects the 7805 from reverse voltages from the output capacitor, when the battery power is switched Off.
Change C1 to a 100nF and add a 47uF across C3.

I would use 1N4007 diodes, they are inexpensive
E

 

Hi Psy,
D3 protects the 7805 from reverse voltages from the output capacitor, when the battery power is switched Off.
Change C1 to a 100nF and add a 47uF across C3.

I would use 1N4007 diodes, they are inexpensive
E

So, something like this:


Also, 7805 datasheet recommends Ceramic Disc for C3. Should any other capacitor be of any specific type?

 

The 0.1 mfd capacitor is supposed to be closer than one inch from the regulator input. Some app notes say closer than 1 cm.

 

The 0.1 mfd capacitor is supposed to be closer than one inch from the regulator input. Some app notes say closer than 1 cm.

What means "mfd"? And I have now 2x 0.1uF.
And I think I can place it closer than that because from what I did yesterday, the PCB for these components is around 4cm x 4cm.

 

What means "mfd"? And I have now 2x 0.1uF.
And I think I can place it closer than that because from what I did yesterday, the PCB for these components is around 4cm x 4cm.

The answer is that "mfd"="uF. ", for those of us not having adequate font capabilities. It used to always be abbreviated that way.

 

hi,

 

The answer is that "mfd"="uF. ", for those of us not having adequate font capabilities. It used to always be abbreviated that way.

I'm not sure I understand what that means. I mean, you have appropriate symbols for the most common things we need in electronics, from the Text Edition menus. And even so, typing an 'u' or an 'm' before the 'F', unless you're russian or chinese / japanese or some such with those weird chars, don't need any special font capabilities, I guess!

hi,
View attachment 315208

I know the difference metween 'uF' and 'mF'. I didn't know was what "mfd" stand for. It could even be milifarad or microfarad!

 

NO COMMENT ABOUT THAT!! If you do not understand a common abbreviation and THEN want to challenge it. Oh Well.