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Arduino Uno R4 WiFi LESSON 2 SUPPLEMENTAL: Calculating Current Limiting Resistor for LED
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- Опубликовано: 1 фев 2024
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In this video I show you how to get started with the Arduino R4 Wifi. I will show you how to correctly.
[Disclosure of Material Connection: I am a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. ]
#arduinor4wifi
#currentlimitingresistor
#tutorial
These clarifications are much needed. Please continue. Those who don't want them can choose to skip but the sensible rest of us will watch.
A VERY HELPFULL Supplemental Lesson.
Always go the extra mile when questions arise.
Your explanations help me explain it to the next person.
Very clear explanation.
The Uno R4 is not built to light up LED s to the brightest value, but to give signals what can control many things, even if in some cases must be amplified.
The max. value of 8 ma not means that we must to draw always that value from the R4, we can draw less , and to stay safe.
Very glad you did this. I had no idea the R3 could be designed for 20mA, but the R4 had to be designed not to have 8mA. Great job. Bob
I'm so happy that you've begun this R4 series. I'm also happy that you've covered this maximum pin current issue, before I bought one and promptly burned it out by going over 8 mA. I am anxiously waiting for your next R4 discussion. Thank you.
Love this lesson! You need to know these things when building a circuit. Thank you for explaining when most people just pass over these essential concepts
As always Paul! your videos explain exceptionally more detailed information then most content providers supply. This is the reason i love following your videos. Keep up the excellent content sir. Long time follower.
Hello Paul, the supplemental lessons are just what we need. Pls keep them coming.
I really enjoyed this detailed explanation! Please keep making the supplemental video's, they great!
Thanks a lot! I always tryed not to burn the LED, but your explanation enlighted me!
This is especially important considering the R4 cost over 25 dollars lol. Excellent presentations Mr. McWhorter...
Perfectly expalined, in the design industry you always have to have safety in mind! An arduino only costs more or less $20, but having this mindset really helps when you're designing a multimillion dollar equipment for a client👍
You've done a great job describing how you could damage your Arduino if the resistor is too small, but I would also mention the downside of the resistor being too big. Since we can see our red LED light up just fine, it seems like there's no downside, which is pretty much true when using a 1K resistor. However, if the resistor is too big (for instance 100K) the LED light will be very dim, possibly so dim that you won't be able to see it at all. In our case, we can see the LED just fine with the 1K resistor, no there's no reason to try to reduce it. (That may be different with the blue LED, but we're not doing anything "special" enough to use a blue LED yet. 🙂
By the way, I tried a 10K resistor, and the LED was still plenty bright enough to see, so I'm tempted to just leave it at 10K.
Also, it might be good to mention that just because the Arduino can drive 8 mA, that doesn't mean that you have to make it drive that much. In general, less current is better if you can get away with it, because in many situations, you'll be powering your creation with a battery, and if you use less current, the battery will last longer. Less current also tends to stress electrical parts less, so that they last longer.
extra lessons helpful paul. Im a qualified electrician now playing with electronics and we barely touched on the lower voltage stuff it during college. im used to the higher voltages and although i know ohms law well its good to get a refresher of basics. Not gonna lie it helped me with little details and im experienced more than most. I didnt know the R4 had reduced the output to 8mA for example. The circuits ive built are on the r3 and its good to know before i just moved my code over and blew mine up :)
Very good supplemental!
Hi Paul, thanks for the supplement. However my main reason for replying is thst I have just taken
your course on Fusion 360 and as a result I now consider myself to be reasonably proficient. I am 83 years of age and enjoying my recently aquired skill (using it almost daily). Keep up the good work. I already suport you on Patreon. Best Regards Trevor.
Fantastic!
The supplementary lesson about the resister sizing and their location was very helpful. I am going to as far as possible put the resister before the LED so as it will apply to all instances such as the RGB LEDS. Going through the sizing again was great revision, Thanks.
Great lesson Paul. The extra detail is welcome. I always value understanding the “why” of what we do! I do not like to just blindly accept stuff as I know assumptions are being made and that is often an accident waiting to happen. Thank you.
I think Supplemental lessons are good!
Thank you for the clarification of the circuit design regarding the calculation of the current limiting resistor in your supplemental lesson two. i'm all for protecting my Uno R4. This is a valuable lesson.
Perfect! I'm a little rusty on my Ohm's law, but thank you for the refresher. Subscribed.
Thanks for additional discussion on this topic.
Paul thanks for your guidance. You nailed it explaining what would happen if LED shorted. Better to be safe than sorry.
Hi Mr. McWhorter. I'm angry I missed of the live session but I am definitely watching the replay. Thank you for uploading this lesson.
Thanks for the explanation it cleared up a lot of confusion , great lesson
Glad it was helpful!
Paul, please always create a supplemental lesson whenever you see that there is a lot of confusion!
Catching up on the lessons...many thanks for clarifying this topic. In my case, the confusion comes from my knowledge of circuits being based solely on solving circuit equations in physics class (long time ago).
As always, another great video! Very helpful in driving in the fact that 8mA was enough for the Arduino uno R4.
Hi Paul! This is the video giving me good insight ! Thanks so much! Jack Lam from Hong Kong
Very good supplement on the sizing of the current limiting resistor, got it1000 ohms
Great work Paul.
Very practical information. Thank you.
Enjoyed the additional video. Great information around designing circuits.
Supplimental comments are good
Excellent and much appreciated explanation!!
Glad you enjoyed it!
This is great. Something i was confused on. Thank you for spending the time explaining it
Definitely a great addition the suplemental lessons!
Glad you think so!
Very glad for this, clear explanation and Lot of useful knowledge. Thank you for that. Hopefully there will be more of these suplemental lessons.
Thanks for the supplemental info. Always best to design for worst case scenario (saves the magic smoke!).
This is the right way, there is to many king of resistors
Excellent tutorials, thank you.
Thank you for the video Paul. Really interesting topic. This is the kind of thing we can make mistales with.
Good lesson. It was good to know the R4 can only handle 8mA of current.
Excellent supplemental lesson!!
I believe we could use 2 330 ohm resistors in series if we wanted to get closer to the calculated resistance.
Or would that be too close depending on tolerance of the resisterors?
Very helpful..Good to know 8 ma current limit for R4
It was very clear and usefull.
This was great!
I will follow this series of lessons about R4 just because of the 8mA issue. Many of the reviews of the R4 missed the 8mA issue and used the standard 220 Ohm resistor with the blinking LED example. Most boards survived as far as i have seen. But how many other projects designed for R3 will break the R4? How many components from earlier kits will break the R4? That's why I wan to follow this series. Watch you redo your old projects and see if you need to make any changes. I have seen most of older Arduino lessons and many of the Raspberry Pi and Pico lessons too.
If you see a lot of questions or confusion then it is great if you can come back and dive into the subject a little bit deeper. Also the name of the game isn't to get as close to 8mA as possible. The name of the game is to make that LED bright enough while still being on the safe side.
Thanks for rerunning the old Arduino lessons modifying them for R4. And add some new cool stuff.
Nice Supplement for us beginners.
The current (amperage) in a series circuit is the same, anywhere you measure it, within that series circuit. Using that rule as a principal, I have never gotten mixed up with voltage drops skewing other calculations.
Nice addition really helped nail it home
Teaching fail safe is a good idea. This also allows for someone plugging the 5v into the wrong track on the breadboard, etc.
This is a good addition. I saw the issue with the original lessen and had to search why you went from 330 in the R3 lesson to 625 here. One big concern I have backward compatibility with previous projects and with existing boards that are used with the R3. Examples would include the seven segment displays, the OLED displays, temperature probs. These all draw some amount of current. Would these not be suitable for the R4 without some changes? - That is something to think about with future lessons or as a stand alone lesson at some point on the compatibility issues caused by the new 8 mA limit for the pins.
We have been warned. Thank-you! Keep up the good work.
Great, well done
It was an excellent explanation. Could my teacher also teach like this.
always helpful the more info you have
This was not even a factor I was thinking about. Since I have no experience with circuits, I had no idea that the LED would also drop the voltage in a significant manner. I had no idea that the LED was considered a "diode" ; just learned that in this video. This was definitely helpful to understand why 1000ohms resistor was the safest bet.
The Question I had in my mind was whether or not I could have two 330 Ohms resistors one after another to add up to 660ohms resistance? Would that not be within the safe range since its above 625? I would try it myself, however I'm scared of frying my Arduino like an omelet if it didn't work.
Yes, I Agree, in case of short circuit LED, that resistor should be 625 Ohm or more, maybe Paul can draw a transistor or Mosfet circuit to the output of R4 so can be safely draw 20mA as the R3 does ? idea for R4 shield maybe :-)
There is also human vision is not likely to see any difference in the brightness of an 8mA vs 4 mA thru an LED -- brightness level changes are seen at the bottom end of current flow
This was very useful, thank you
I'm new to this but you mentioned V = IR which is given. You're saying it can be exponential and I'm trying to understand since that equation is linear. Possibly the unit difference?
Great explanation! I'm just wondering if you could use two 330R resistors to get the same results as only using one 1K?
This was VERY helpful. 😀
Do they make any kind of overcurrent protection that could be used as a backup in case a mistake is made?
Hi Paul, loving your tutorial and process! Can you tell me what software do you use for creating your videos?
I am using wirecast. It is a program you have to pay for but is very powerful. OBS is a free software that will do a lot of good stuff. If you dont want to buy wirecast, try out OBS
Good morning!
The voltage drop across LEDs is never the same. Some can be as low as 1.2 volts while others can be over 3 volts.
We are learning about microcontrollers and not fine-tuning a product, let's keep the circuits generic and save the Arduino.
Arduino lives matter.
The problem with stressing these generic LEDs is that they can get too hot, dropping their internal resistance, increasing the current flow, and shorting out. The short circuit then blows the internal connections open, stopping all current flow. But, by then, the damage has been done to that port on your tiny microcontroller IC.
So, it would be best if you always erred on caution.
The top speed listed on your automobile's speedometer is the maximum, not the recommended speed.
@danblankenship5744
I never knew that about the speedometer😁😁
I was wondering if someone tell me a good numerical method book having good examples? thank you 🙏
are there any internal pullup resistors in uno r4 just like we had in uno r3?
No annoyance at all, always 👍 for the supplemental videos. And yeah this video makes sense to me. 👍
can't we use resistor before led .it will also do same in case it will protect led as well as arduino
It behaves exactly the same independent of what side of the LED you put it on.
I think your arguments are valid. You are using an LED, not a diode. You need to draw the arrows on the diode to indicate it is an LED.
An LED IS a diode. The clue is in the name. LED = light emitting diode.
Another option would be to use two 330Ω resistors in series for a total of 660Ω.
Yes, that is a great option. Would allow you to safely get a little more brightness from the LED.
👍🙂
Put 330\270's in my draw and switched to 1K. You can't be too careful.
I missed this, didn't pick up it was happening - hey ho
hey why don"t you release the other video instead of making us wait , i am kinda impatient
Since we're talking about resistors, I'll shamelessly promote my video on sorting and storing resistors: ruclips.net/video/2QLwzy4QgBk/видео.html
Is there something in a comment that prevents it from being posted by RUclips?
Now, you have made the same comment at least twice. Your comments are being published.
I have yet to see the comments with the link to the RUclips video. Have you, or anybody.@@paulmcwhorter
Once again, my comment for lesson 02 was DROPPED. I have replaced it. Can anyone see that comment in the comments for lesson 02? Can you follow the links?
I dont think your comments are being dropped. I think you are not waiting for them to be reviewed, and expect to see them immediately. I review all comments before publishing, and I review comments once a day.
Forgive me, but I don't think that is the case. The dropped comments on lesson 01 never came back. And the dropped comment on lesson 02 was up for many hours yesterday but gone this morning. NEWS FLASH: The comment I put into lesson 02 was just dropped within the hour. I am going to repeat that comment in this stream in a minute or two.@@paulmcwhorter
hmmm... I think choosing the 1k resistor is fine. But i also think your argumentation is not correct. If your argumentation is true, then the Arduino designers had added a resistor by default that only allows max 8mA. But they didn't add that resistor, even it mean that if you do it wrong or if your do a short by bad luck, then the Arduino will burn. There is a reason why they didn't add it by default.
Ignore me at your own peril.