This page provides a guide on the construction of the transmitter and provides links to the software used as well as the source code.
All code and related files are linked at the bottom of this page.
The first thing to do is to acquire the necessary software and install it on your computer. The Arduino software is a development software for the programming of the Atmel microcontroller. The Layout Creator is for the circuit design and modification. Once installed continue onto the hardware element.
Software:
Arduino
DIY Layout Creator
All code and related files are linked at the bottom of this page.
The first thing to do is to acquire the necessary software and install it on your computer. The Arduino software is a development software for the programming of the Atmel microcontroller. The Layout Creator is for the circuit design and modification. Once installed continue onto the hardware element.
Software:
Arduino
DIY Layout Creator
The parts can be bought online or via a local hobbyist shop, although some may be easier to get online.
Atmega 328
DAC
OP Amp
Level Shifter
Most of the components are available in any hobbyist shop and easily attainable.
B.O.M (Bill of Materials)
Construction
If you want to alter the original design then open the file Audio FM TX.diy. You may want to add or remove certain parts or change some areas. Otherwise waht you can do is follow the below graphic of the stripboard using the following guidelines:
Black Wire: Negative
Red Wire: Positive (5v)
Blue Wire: Jumper Wire
Yellow: 3.3v
The red/white squares are 'breaks'. These are used to break the continuity of a strip of copper and create circuit tracks to connect components. Using the software different layers can be shown or removed much like Photoshop and it is easy to see where the breaks and jumper wires must go.
Traditionally the way to build a strip board circuit is to start with the breaks, then the jumpers followed by the resistors and building up to the highest components last. Also is is better to use IC sockets where possible, so as not to damage the IC's and also they can be re used in other projects or different board designs.
Before building I recommend prototyping extensively, allowing for modifications and add-ons if required.
Range/Power
The broadcast range is approx a 60 metre radius, depending on the location and elevation. One area that needs further development is the power source. Solar and highly efficient rechargeable batteries is the key here as well as access to sunlight. Ideally the battery(ies) would charge during the daylight hours and keep trickle charging to allow the battery(ies) to not fall to a low enough level so charging would be difficult. This part needs to be tested more once I can get access to some of the newer type of batteries with new technology behind them.
Files:
GPS apk for Android
GPS app source Code
Arduino Source Code
Layout Creator File
OP Amp
Level Shifter
Most of the components are available in any hobbyist shop and easily attainable.
B.O.M (Bill of Materials)
Construction
If you want to alter the original design then open the file Audio FM TX.diy. You may want to add or remove certain parts or change some areas. Otherwise waht you can do is follow the below graphic of the stripboard using the following guidelines:
Black Wire: Negative
Red Wire: Positive (5v)
Blue Wire: Jumper Wire
Yellow: 3.3v
The red/white squares are 'breaks'. These are used to break the continuity of a strip of copper and create circuit tracks to connect components. Using the software different layers can be shown or removed much like Photoshop and it is easy to see where the breaks and jumper wires must go.
Traditionally the way to build a strip board circuit is to start with the breaks, then the jumpers followed by the resistors and building up to the highest components last. Also is is better to use IC sockets where possible, so as not to damage the IC's and also they can be re used in other projects or different board designs.
 |
| Finished Populated Stripboard |
The is a graphic export of the Stripboard design from the DIYLC software which is open source and free..it's very nice and easy to use.
 |
| Blank Stripboard |
It starts off as a blank 100mm X 160mm piece of Stipboard like this one: Roth Elektronic stripboard
 |
| Populated Stripboard |
It then ends up like the one above which is a fully populated and working Audio Player/Fm Transmitter, this can be then put into any kind of box, container, shampoo bottle, water bottle etc..just make sure to take precautions against moisture by using some silicone.
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| SD Card |
The easiest way to use an SD card is to solder a mini Sd card to Full Sd card adapter, and then remove the mini SD card any time audio is to be added. You can of course use an SD card reader for PCB boards, but these are awkward to get and expensive (here) and the above is a simple workaround which I came up with.
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| Testing & Prototyping |
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| Testing the FM Module |
The light comes on when the transmitter is working.( its nice to see, especially at 3 am....)
Range/Power
Files:
GPS apk for Android
GPS app source Code
Arduino Source Code
Layout Creator File
