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Share Your Morse, a JOTA 2013 AVR Electronics Kit project

Components A project by PA1IVO and PA0LEZ.

A link to the non-technical page for the JOTA scouts (in Dutch) can be found here.

Last update: 3 September 2013 - This page will be completed later.....

Idea

To be added here.

Schematic

Experimenteerbordje
Electronic schematic.

Component list

Share Your Morse Badge

Description Name/value Part
AVR Microcontroller ATtiny85V - PDIP IC1
IC socket ASSMANN WSW AR 08 HZL-TT N.A.
Speaker 41.T70P015HLF Ls1
Battery clips 2468 N.A.
Batteries Panasonic Batteries
LR03XWA/B24
Bat1/Bat2
LED Multicomp OVL-3324 LED1
Capacitor Murata RPER71H104K2K1A03B
100 nF
C1
Switches Alps SKHHARA010 S1/S2/S3
Power switch safety pin Veiligheidsspeld
Resistors 100/560/10k Ohm R1/R2/R3

Table 1: Component list.



AVR Selection

Share Your Morse Badge The heart of the logic of this kit is based on a small AVR microprocessor. The selection for a chip in the AVR range is only based on previous experiences with AVRs, and therefore the availablity of software, programmers, and knowledge. A PIC microprocessor should probably also be able to do the job.

The AVR selection was based on the following criteria:

By using the AVR Compare Devices page (Well done!) we selected the ATtiny85V, which has only 8-pins in a DIL housing, a suuply voltage down to 1.8 Volt, and the maximum memory in this range.

The ATtiny85V has two 8-bit timers, where one is used for the morse audio tone and the other as a random number generator to randomly select new 'secrets words'.

Speaker Selection

We looked for a small speaker, being a speaker and not a piezo buzzer. With a real speaker you are able to change the tone frequency, which is not possible with a piezo. The speaker selection was based on the following criteria: It is hard to find small PCB mounted speakers that are not piezos. We found one at Baco in IJmuiden, and one at Farnell. Because of the slightly better tone and the availablility of 16000, we select a small PCB mounted speaker from Farnell.

PCB

To be added here.

Software

The AVR software was developed with Atmel Studio, and therefore written in the C programming language.

Morse tone using PWM

To be added here :-).

Encoding the morse words and program into 512 kB

To be added here :-).

Pictures and movies

Components
All electronic components.



All PCBs.

The batch of 30 PCBs arrived from China.



Movie of a ready badge with a small explanation in Dutch (original video on YouTube).



Improvised movie (in Dutch) of the prototype, taken during a JOTA preparation meeting.



Experimenteerbordje

"Share Your Morse" badge prototype: Software testing.



2013-2016 by Ivo Klinkert, PA1IVO - Contact