Morse Code Oscillator for CW Practice with 555 Timer
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- Опубликовано: 18 сен 2024
- Here is a simple circuit that uses the NE555 Timer IC to make an oscillator to practice Morse code with. When my PCB comes in from JLCPCB I will be 3d printing an enclosure for this circuit, so keep an eye out for that video in the future.
Bill of materials for this project:
1 - 9 or 12v battery (or similar DC power source)
1 - Battery snap (if using battery)
1 - NE555 Timer IC
2 - 20k Resistors
1 - 47 ohm resistor
1 - 50k Potentiometer
1 - 5k Potentiometer
1 - 22pF Ceramic Capacitor
1 - 22uf Electrolytic Capacitor
1 - LED (optional)
1 - 8 ohm speaker
1 - Telegraph Key, button, switch, or other way to complete the circuit.
Links to how the 555 circuit works:
Ben Eater - • Astable 555 timer - 8-...
The Learning Circuit - • How 555 timers Work - ...
Great Scott - • Electronic Basics #26:...
#MorseCode #CW #AmateurRadio #HamRadio
Hi, I am sorry to see you have had some negative comments but as somebody else said these are just trolls and should be ignored. Unfortunately, they are sadly a fact of life on forums and RUclips. They go about posts leaving negative comments presumably trying to get a rise. They also normally contribute nothing in the way of originally material. Your title clearly describes the contents of your video and is why I viewed it. I found it clear and interesting and that you were not afraid to talk about your failures, always a good sign. Many thanks for posting.
I have two suggestions to improve this circuit that I see replicated as is seemingly everywhere.
1. The lower portion of the 10K volume pot is swamped out by the 8 ohm speaker. Replace the 10K pot with a 100 ohm one. Better yet, connect the 100 ohm pot as a variable resistor in series with the speaker. The variable resistor and speaker will form a voltage divider that will work with a reasonable range. You can add a fixed resistor of 10 ohms or so in series if the lowest volume setting is too high.
2. Connect the speaker return lead to the negative rail and move the key so it switches the negative lead from the battery to the circuit. Eliminate the power switch.
Power will only be drawn when the key is closed, so you can walk away without having to switch anything off and no current will be drained from the battery. Connecting this way will also save power when you are sending because no current is drawn when the key is up.
Have fun!
Reply
Those are great suggestions! I'm definitely gonna try that! There's a few things I'd like to do and make a v2, so I'll definitely keep this in mind. I really appreciate you taking the time to watch and write all that to help me out!
@@ErikNonIdle My pleasure. It's nice to see someone pursuing science and engineering as you are.
@@sailatmojo If you look at my channel you'll see I have a bunch of different interests, but I absolutely love playing with electronics and always loving learning more about it and finding new projects to do.
Useful Video , I am gonna make one , Thank you Erik for the video.
Thank you so much! I really appreciate that!
Nice job, young man. Good video. How's the CW practice going?
I don't know how I missed this comment the other day, but thank you! I haven't been practicing as much as I'd like, but I do get on the air occasionally and struggle through a contact or two. The operators always seem to be very understanding and helpful, and I really appreciate that. There's really no better practice than doing it live I feel like.
LICW has me on the Air, it's been a blast
Cool video
Thank you! I really appreciate that!
what happened to the PCB and enclosure?
IC Socket is your friend...
Definitely! Lesson learned! Thanks for watching.
can u able to add a 7 segment display for that?
You certainly could, but it would take a lot more engineering and is beyond the scope of what I made in this video. That's a really good idea, though. Perhaps using a Arduino shield in conjunction with the oscillator would work for that.
Hi, can you give me all the components you used for this project please
I have added a list of materials to the description of this video so everyone can see it. I should have thought to put that up sooner. Please let me know if there is anything else you need or questions you have. Cheers!
22uF electrolytic capacitor equal to how many volt?
If I understand your question correctly, 22uF electrolytic caps are rated to 25V, which is way more than you'll use in this project.
@@ErikNonIdle thank you, and why use speaker not buzzer?
@@iqmalmal5993 You absolutely could if you wanted, but I wanted the speaker for the clearer tones and so it's a little more pleasant to listen to. Using a piezo buzzer would work just as well if you just wanted the thing to make noise.
Can we use 12 volt power supply instead of 9 volt?
Great question! The NE555 datasheet says that the absolute maximum VCC is 18v with a recommended max of 16v, so using a 12v power supply should be perfectly fine. You may have to adjust some of the resistor values if there is a specific frequency you are looking for, but if you are using potentiometers like I do in the video, you should be able to tune it how you like.
As Erik said, yes you can. The good news is that the thresholds are set as percentages of the VCC, so you should be able to use the same RC values without noticing a frequency change (that goes for when the battery runs down as well).
I don’t have a 20-25pF capacitor, what is the maximum leeway?
That capacitor works in tandem with R1 and R2 to control the duty cycle and frequency of the output, so the 20pf isn't a critical value. According to the NE555 datasheet you can calculate the Output High duration with:
Th = 0.693(R1 + R2)C
and Output Low with:
Tl = 0.693(R2)C
So if you want a 50% duty cycle and particular frequency you can plug those numbers in for the capacitor you have and adjust R1 and R2 accordingly. There are also calculators online that will do the math for you. Long story short, you can absolutely switch out that capacitor pretty freely with whatever the lowest capacitance you have is, you just might have to adjust your R1 and R2 to compensate a bit if you are looking for a particular frequency.
@@ErikNonIdle Thanks for the detailed answer, I already have R1 and R2 (with the same values as yours) and I was wondering if I could just swap it for a 10pF capacitor. I also have a 100pF, which one would work better?
@@austincarter825 oh, in that case I would probably use the 10pf. You'll get higher frequencies out of the gate, but if you use a potentiometer on R2, you can bring those high frequencies back down.
@@ErikNonIdle If I use a 10pF capacitor, which would be the best value for R2? I may have some others.
@@austincarter825 According to a calculator from digi-key, a 50k resistor would be very close to exactly the same as the 20pf cap values. 40k is also pretty close. Keep in mind, none of these values are critical to the function of the circuit actually working, just the tone and frequency. I would definitely experiment with different values on a breadboard to see what you like best. I also just got in some PCBs for this circuit that I am planning to mess with and probably sell if anyone is interested. More on that in an upcoming video.
Nothing explained
I went over the electrical diagram as well as several iterations on perfboard and did a demonstration of the project working. I'm sorry it wasn't explained well enough. If you have any questions, I'd be happy to answer them for you!
@@ErikNonIdle what is a morse code oscillator? what's its purpose? what do you do with it? why is it needed?
@@kurusb7792 Like the title says, it's for CW practice. It's so you can practice sending morse code without actually transmitting on-air. It's essentially the same as the MFJ-557, but it's a lot cheaper than $75 to make yourself and a fun project if you like playing with electronics.
I thought the video was really good, don't listen to him. Some people just comment to hate.
@@austincarter825 Hey, I really appreciate that, Austin! If you have any questions about anything, I'd gladly answer!
Waste of time
Sorry you feel that way. What's wrong with the project?
@@ErikNonIdlei also made this circuit but it didn't worked
@@graphicsrevolution3728 Interesting. I've made this exact circuit several times, and other people have used this video with success. I would recommend checking for solder bridges or faulty components. Also check the 555 has the same layout and orientation as the one I am using.