HOMEBREW POCKET MORSE TUTOR
A bit off topic I know but will eventually help me learn Morse Code for my portable ops.
-.-.- Pocket Morse Tutor from an idea by DJ5AM
The Pocket Morse Tutor (PMT) uses a programmed ATtiny45 chip from Atmel the programme and circuit idea belong to DJ5AM Steffen, you can see his original article with the circuit diagram and photo’s on his website:
The PMT is a fun project and easy to build and would be ideal for clubs and schools, the circuit is built around the ATtiny45 chip, power is supplied by a 3v button (coin) cell and the output is enough to drive a pair of MP3 player type ear-buds.
List of parts:
At the time of writing the price was 7.50 Euro postage inside Germany included, on his website he has a link where the HEX-Code can be downloaded.
1x 8 pin chip socket.
1x 10k linear pot, the value is not critical what ever you have in your junk box, a smaller value will increase power consumption.
This will change the character per minute speed from 30 to 150 using the Farnsworth timing method.
2x push-button switches, S1= start a lesson and S2 = proceed to the next lesson, these should be flat enough that the lid of the tin does not press down on them.
1x 10nF cap.
1x 3v battery with holder.
1x 100nF coupling cap for the ear-buds which are usually about 32 Ohms, you may have to experiment any cap from 1nF - 4, 7µF should work, DL2LTO used a 470nF cap in series with a 1k2 resistor for his 64 Ohm ear-buds, the resistor could also be a pot to give some volume control, experimenting is fun.
All the passive components’ I was able to get from my junk-box and I built the circuit on a scrap piece of Perfboard.
Have a look at DL2LTO’s excellent website for details of the Perfboard and circuit diagram he used for this project to fit into a very small peppermint tin:
Click on the link to the right of the Perfboard diagrams to open a larger picture.
The power drain of the circuit in sleep-mode is under 0.2 uA so Steffen recommends that no switching is needed for the power supply, but as the battery needs to be removed and replaced for the Q-code lessons Uli, DL2LTO has included a jumper switch as he found removing the button cell a bit fiddly, replacing the battery always acts as a reset so you will have to start from the beginning.
When you insert the battery if all is well you should hear the welcome text:
Morsetutor 1.9 de DJ5AM
(1.9 is the current version at the time of writing) after which the PMT goes into sleep mode until a button is pressed:
There are two buttons S1 which is START and S2 which is LESSON
The first time button START is pressed lesson 10 (random, all characters) will be sent, PMT goes into sleep mode again, if you press START again lesson 10 is repeated if you want to move on to lesson 1 you need to press LESSON and START (see text further down the page).
There are ten lessons using the Koch method:
1: k m u r (ka) (ar)
2: e s n a
3: p t l w
4: i . j z
5: - f o y
6: , v g 5
7: / q 9 2
8: h 3 8 b
9: ? 4 7 c
10: 1 d 6 0 x = (all characters)
Included is also a lesson with Q-Code groups, more about that later.
Pressing START you will hear a long tone (confirmation that new characters will be sent) followed by short tones = the lesson number, 24 groups of 5 characters will be sent randomly for each lesson, to repeat the same lesson press START again, the short tones for the lesson number will be repeated and the characters will again be random.
To go to the next lesson press LESSON and START together.
The lessons cannot chosen individually they follow one after the other, the new characters in the lesson will be sent first followed by the ones already learnt.
After the 10th lesson the PMT goes back to the 1st.
Lessons start with KA and end with AR
Lesson is repeated by pressing START
Next Lesson press LESSON and START
Lessons with new characters will be confirmed by a long tone.
Short tones indicate lesson number
Pressing the LESSON button for longer than one second will stop the current lesson (long tone).
When you have had all the fun you can take with learning the characters remove the battery, press and hold LESSON and replace the battery (two long tones confirmation) you are now in the Q-Code lesson mode, pressing START the PMT will send 24 groups of Q-Codes, pressing LESSON for longer than one second will stop the Q-Code lesson.
Remember, removing and replacing the battery will reset the PMT, you will hear the welcome text and lesson 10 also the memory of your progress will be lost.
I hope you will have as much fun with this great little project as I have, when you have boxed your PMT send a photo of it to DL5AM Steffen: Steffen.Braun@web.de he will be happy to include your PMT on his website.
And now a word of warning.
If like me you use public transport to and from work and like me you will use this time to learn morse code with your PMT you will get some strange looks when you sit there with the other passengers all with their MP3 players running and you take out your PMT from your breast pocket to change the lesson and they see your ear-buds are connected to a Peppermint Tin, the first voice you will hear will probably be from a child sitting next to you with their Mother, " Mummy why is that man listening to his Peppermint Tin" the answer will probably be something like "Shhh darling, its very rude to stare" as she puts an arm protectively around her child.
I am in no way affiliated with DL5AM Steffen, I am just happy to pass on details of his project translated as best I can into English.
Vy 73 de Colin DD5CF / G1ZOS .-.-.
