Assembling a Niftymitter V0.24 Board - a Short Range FM Transmitter

Intro: Assembling a Niftymitter V0.24 Board - a Short Range FM Transmitter

This Instructable will guide you through assembling the circuit for Niftymitter, an open source mini FM transmitter. The circuit uses a free running oscillator and is based on Tetsuo Kogawa's Simplest FM transmitter.

The project is housed at www.openthing.org/products/niftymitter

Step 1: What You Need

• Complete Parts List [.xls]
• PCB Layout v0.24 [.png]
  
  • The PCB source is designed for etching onto copperplate, using iron on acetate (such as that described here) or using Michael Shorter's laser engraving method described here [instructables].
    
• Circuit assembly diagram for etched PCB [.png]
  
  You will also need the following tools:
  Soldering iron, kit and solder.
  Wire snips.

Step 2: Solder on the Resistors and Capacitors

Place comonents flush up against the board from above. After soldering the legs onto the pads, trim of the excess.
Start by soldering all the resistors. Follow with all the capacitors and the jumper lead. Ensure that the electrolytic capacitor is oriented as described on the circuit layout diagram, the negative side away from the socket.

Step 3: Solder on the Socket, Coil and Trimcap

Next solder on the socket. Take care to ensure the socket is solidly soldered on. Solder on the trimcap, taking care to orient the flat side as shown. Then add the coil. The instructable for making the coils is here.

Step 4: Solder on the Transistor

Finally add the transistor, taking care to orient the pins correctly.

Step 5: Add the Power Connections

Solder on the positive lead from the PP3 clip to +9V. Add a short length of wire to the ground connection.

Step 6: Prepare the Switch

Bend the positive lead of the switch LED around one of the switch pole legs as shown. Solder and trim the LED leg as shown. Bend over the remaining LED leg to make a loop.

Comments

[SulabD]

Can i use 2N3904 transistor??

[royshearer]

I don't know I'm afraid. The design comes from Tetsuo Kogawa, so might be worth asking him:
http://anarchy.translocal.jp/

[Txer]

I don't mean to be funny here .but how does a 10pf manage to get you on the fm band I only find that 30pf and above gets me on fm band .or is because in different country's the fm band is different ?

[royshearer]

I'm afraid I have no idea why it works but the 10pf has been fine evry time for me in the UK..

[lseemann]

nice work. i want to build one. can i replace the 9V battery with USB connector? Would it be enough its 5V 1A to power the device?

[sciencetor2]

are solder lines on an all purpose radioshack pcb not an option here as an alternative to etching?

[royshearer]

I'm not familiar with that - tell me more!

[sciencetor2]

well basically its a prototyping board, its a prepunched pcb grid with each hole having a copper circle around it, and you draw paths with solder rather than making a print of the paths ahead of time, would using solder as thhe conductor be an issue?

[jtc10512]

is that pink thing in the center the tuner?

[royshearer]

Yes, it is the trimmer capacitor, tuned with a trim tool or screwdriver.

[alexanderall]

Where does the switch go on the on the pcb?

[burdockwing]

so wait what does this exactly do?

[royshearer]

Niftymitter broadcasts any audio signal that you put into it on FM radio over about a 20m radius so that you can listen in using a FM radio. like an iTrip.

[technozook]

could you post a scamatic cus i cant etch my own board

[royshearer]

Schematics can be found at Tetsuo's site here:
http://www.translocal.jp/radio/micro/howtosimplestTX.html

Or as a .png here:
http://niftymitter.googlecode.com/files/niftymitter%200.23%20electronics%20schematic.png

Or as a eaglecad .sch (not a very good one at the moment to be honest - please improve) here:
http://niftymitter.googlecode.com/files/0.23.sch

[bobrob5k]

is it possible to make this work with out a battery?

[royshearer]

I would imagine so, just use a 9v power supply in place of the battery?

[coolacid]

What goes in the Y-ish symbol between the 9V and the GND?

[cliffyd]

its for an antenna wire.

[royshearer]

 That is a hole to solder on an antenna if you fancy. I don't know much about how one should do that. Will annotate it better in future versions.