Free Radio Friend Finder

The frff project is not only a software project. It also provides a hardware. The board design is done with the eagle software. Many thanks to CadSoft for letting Non-Profit projects use their software for free.

Schematics

hardware schematics

Programm port

This design is a more or less dest board for our project. Therefore we have the possibility to programm the Atmel while he is on the board. The Atmel needs SCK, MISO, MOSI and reset. In order to keep the costs for a programming interface very low we used the programming interface as described by Guido. The cable should not be longer than 70cm. At the beginning of our project we used our Laptop for programming the chip. Unfortunatelly we discovered a lot of problems with failed verify. As soon as we switched to use the desctop all problems where gone.
Pin Name at Atmel Pin Number on Atmel32 Protection Resistor Pin Name on parallel port Pin Number on parallel port
Reset MOSI MISO SCK GND
9 6 7 8 11,31
-- 470 Ohm 220 Ohm 470 Ohm --
Init D0 Busy Strobe GND
16 2 11 1 18

Micro Controller Power and Clock Supply

Thanks to the USB mania 5 Volt are very common now.

Digital Analog Converter for Low Frequency output

The Operational Aplifier (IC2) is descriped on the National Semiconstructor Homepage.

Datasheet

Bill of Materials

Exported from Mainboard.sch at  7/04/2006 20:46:06 

EAGLE Version 4.16r1 Copyright (c) 1988-2006 CadSoft

Part     Value          Device          Package      Library  Sheet

C01      100n           C-EU075-032X103 C075-032X103 rcl      1
C02      100n           C-EU075-032X103 C075-032X103 rcl      1
C03      100n           C-EU075-032X103 C075-032X103 rcl      1
C04      100n           C-EU075-032X103 C075-032X103 rcl      1
IC1      MEGA323-P      MEGA323-P       DIL40        atmel    1
IC2      LM741P         LM741P          DIL08        linear   1
Q1       14,318         XTAL            Q            special  1
R01      10k            R-EU_0207/10    0207/10      rcl      1
R02      2k             R-EU_0207/10    0207/10      rcl      1
R03                     R-TRIMM3202     RTRIM3202    rcl      1
R10      160k           R-EU_0207/10    0207/10      rcl      1
R11      82k            R-EU_0207/10    0207/10      rcl      1
R12      39k            R-EU_0207/10    0207/10      rcl      1
R13      20k            R-EU_0207/10    0207/10      rcl      1
R14      10k            R-EU_0207/10    0207/10      rcl      1
SV1                     MA05-2          MA05-2       con-lstb 1

Atmel description

Atmel has developed microcontrollers from very small and cheep ones up to very big ones with a lot of features. For nearly all of them are GCC and libc support available. In order to programm the microcrontroller with linux there are two project available, UISP and AVR-DUDE. More information about the used microcontroller for this project can be found in the Atmel Product Overview Page or in the Datasheets:

Atmel Mega 16

Product Card
Summary
Documentation

Atmel Mega 32

Product Card
Summary
Documentation

Where to buy

We got all our parts from the german mail order company Reichelt, but we are sure that there is a electronic shop or mail order company also in your country.

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