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Voltage Divider same result as Logic Level Converter?

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jBo
 jBo
(@jbo)
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Joined: 3 years ago
Posts: 100
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Hi All,

After a hiatus(*), I'm back trying some electronics experiments. I want to control a DFPlayer Mini with an Arduino Nano.

There are several good video tutorials, but I'm following this one.

I have a clone module, but the original DFRobot specs are here.

OK, so I'm following along, and the guy explains the DFPlayer can Tx to the Arduino Rx just fine. However, the DFPlayer is not 5V tolerant, so he uses a voltage divider for the Arduino Tx to the DFPlayer Rx.

This is cool in theory. It seems simple, and I want to learn new things. The problem is that I don't have the resistor values he uses. I thought I had a decent selection, but I guess not. I got frustrated, check another tutorial on the same application, which used some different values of resistors, which I also did not have. Am I the only one who's ever had this problem? That there's always just one more component you need to source, and then wait for? Sorry, that's not my real question.

Actually, he did say "a voltage divider or other method." I remembered @dronebot Workshop video on converting logic levels, and so I do have some of those 3.3V to 5V converters, tiny little things. They are bi-directional. Sorry I could not find the Dronebot video which mentions them. It's not the same one as the buck/boost converters and such.

My real question is, could this logic level converter be a decent replacement? At least for protecting the Rx input on the DFPlayer Mini?

Thank you,

John

* After getting a first 3D printer of my own, I "discovered" the need for several hundred objects. Printing them took a lot of time 😀 

In theory, theory and practice are the same.
In practice, they're different.


   
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Will
 Will
(@will)
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Joined: 3 years ago
Posts: 2504
 

@jbo

The level shifters are exactly what you need (provided that can supply the current required for your circuit).

Don't put down that filament roll yet, if you've only discovered the need for several hundred new objects then you're not even CLOSE to being done 🙂 They're addictive, especially when you start designing your own parts.

Anything seems possible when you don't know what you're talking about.


   
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jBo
 jBo
(@jbo)
Member
Joined: 3 years ago
Posts: 100
Topic starter  

@will 

Thanks very much for that advice. 

Regarding filament, ha, you're correct, addictive indeed. 

In theory, theory and practice are the same.
In practice, they're different.


   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 3 years ago
Posts: 6662
 

@jbo Just set up a spread sheet to give you the ratio of the spec'd resistors, then propagate the ratio and start entering one of the R values that you have. When the result is also one that you have, you are done. HOWEVER I would use the Logic Level converter.

BTW, if I could think of even a few dozen uses for a 3D printer I would buy one but so far I am stumped.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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jBo
 jBo
(@jbo)
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Joined: 3 years ago
Posts: 100
Topic starter  

@zander Thanks for the recommendation. Sorry it took me awhile to get back to you. I finally bit the bullet and looked into the voltage dividers, tried the equations, fooled around with a calculator, and took another look at what resistors I did have on hand. (Turns out it was more than I had remembered, but I was just storing them wrong; another story). Logic Level converter still the way to go, yes.

Regarding 3D printers, each to his own. For my own wild reasons, I like to think of recycling plastics in order to make cool things. See photo - yes, they tend to look like trash, though the electronics work fine, and I've learned a lot. It occurred to me that although I watch the demos and build videos of Ben Heck, I just don't have the craft skills he has 😥   So for me, designing and making an enclosure for my temperature/humidity display is a worthwhile use for a 3D printer. Cheers!

trash enclosure

 

In theory, theory and practice are the same.
In practice, they're different.


   
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