Hi,
There isn't a problem with this circuit(yet).
I am just wondering if this Schematic is okay.
Sorry if it is terrible(it's my first one drawn by hand).
Here it is:
I have not really researched the proper resistor for the speaker.
I Know I am using the wrong symbol for the speaker.
Going to change it, but don't know what the symbol is supposed to be.
Thank you very much.
google for; led symbol, piezo speaker symbol ............
show picture of the speaker
Your "R2" is much too low. The LED spec of 30ma is a MAX. typically a 800 to 1200 provides a good indication, closer to 500 if you want it bright.
I'm not familiar with the FireBeetle but he ESP-32 cannot provide 30ma. I'm not sure the actual output current spec off hand but I would limit the output current to 10ma at the most.
Oh,
I got that value from a LED resistor calculator.
groundFungus helped me with that see:
@tom321
I have too many speakers.
No idea which one should I pick.
Photos and list coming tomorrow.
I think I have these:
Thank you very much.
Hmm I could drive the LED with the FireBeetle.
No idea If it is still working.
Hope I did not break it.
I entered this and got:
I2C pullups?
No details of the LDR, so can't tell if the 10k is appropriate
So you calculated 130 ohms, but showed 75? May I ask why? In the case you're showing, I'd be going up in resistance, not down, as 20 mA is really asking a lot of most processors, though I don't know the specifics of your firebeetle.
And yes, check your processor's data sheet carefully for the specification of output current (Ioh) in this case. Also, verify that it isn't better to wire the LED so the output goes low to turn it on(Iol(pronounced "eye-oh-ell"), as some processors don't have symmetrical output currents high and low.
Not sure that pronunciation is very useful, but
Ioh stands for current (I) when the output is high;
Iol stands for current (I) when the output is low.
It is unfortunate that this forum uses a font where the uppercase 'i' looks the same as a lowercase 'L'
That's the point I was making. IOL and LOL look the same, if all lower case. At any rate, you got my intent.
Is that like pin sinking?
SGP-40 Docs:
I don’t have the LDR’s specs.
I was using it that way with my uno with success.
But the voltage is different.
As for the Photo JohnRob said that the resistor was too low so I calculated again using worst case values.
Original one can be found at: Sending and Receiving IR signals - #19 by v205
I was going to recalculate the Resistor again.
sorry.
Yes, my point is to always look at the processor specs. It may be that it can do a better job sinking than sourcing, in which case you want to drive the LED with a low output, is all. It's a design detail many miss.
Ioh will be sourcing;
Iol will be sinking (hence may be shown as a negative value in the datasheet).
Ok, I will look up the chip's IoH and IoI.
I wanted to use sinking.
Problem is that I have no idea how to make the Library I am using to send IR signals compatible with sinking.
Note this was was also mentioned in Sending and Receiving IR signals - #19 by v205
Thank you very much.
Photos of speakers coming up.
No idea which one to use.
About theses led calculations …..
Vf for an IR led is about 2v
So… for 20mA R = 1300/20 = 65ohm .
So 75 is probably fine , giving slightly less current.
No idea about the pullups.
Need to measure the resistance of the LDR.
8 Ohm speaker can not be connected directly to Arduino use amplifier LM386, big buzzer can be connected directly to Arduino, small one = need better picture
https://www.circuitbasics.com/what-is-a-buzzer/#:~:text=Buzzers%20can%20be%20categorized%20into,audio%20signal%20to%20produce%20sound.
The maximum output of an ESP32 GPIO pin is 12mA. If you want to drive that IR led at maximum power (30mA) then use an NPN transistor (1k base resistor) on the low side and connect the led ( with current limiting resistor (say 150 ohms) to the 5v supply.
That also effects a signal inversion, nicely addressing the issue in #13. Good idea.
@tom321
I have a passive and active buzzer.
Both are the same from factor so I have no preference.
The active one has a “remove seal after washing” sticker.
I did not remove that Because if I do I won’t be able to tell the difference.
Earlier I tried using both and the passive one sounds much better.
I don’t trust the distributor’s documentation. Docs from this company nearly fried my IR receiver.
Thank you very much.
Photos of both coming latter.
This is from the SP32-WROOM-32E & WROOM-32UE Datasheet v1.6:
