Mobile phones work in lifts (elevators as you say over the pond). It's unlikely that you could make your bedroom more shielded than that. However, I am sure someone will be willing to offer to try, for a price. Probably the same person than spreads fear around the internet about the "dangers".
You can change the wavelength while it is passing through the material, but when it comes out again it will return to what it originally was. To change the wavelength in air you would need to change the energy of the photons, which is definitely not trivial!
You don't say what it's for so I don't know if this is at all applicable but you can get NdFeB permanent magnets quite cheaply nowadays. They go up to over 1.5T.
I think having the magnet on permanently might cause you problems and will certainly waste your batteries. Do it the other way round. Put a small permanent magnet on the bird and then use an electromagnet to "push" that when pulsed.
Alternatively you could try and find a solenoid (as used on...
I'm not familiar with the Arduino. Are you trying to use an analogue output or a pulse width modulated (PWM) output? If it's an analogue output I think you will struggle because most interface cards have very limited output current capability. If it's a PWM output then you need to assume it acts...
Putting a load between the emitter and ground doesn't work on an npn transistor. When current flows through the load, the emitter voltage rises and Vbe falls partially switching off the transistor. Put the load between the 12V supply and the collector.
I don't see any connection between the midpoint of the two supply batteries, pin 3 and your input's "zero" side. Those three things need to be connected together.
As has been pointed out, your supply only seems to be +/-9V. That should be just about enough though.
We can understand them because we invented them. So as an electrical engineer I can understand circuit theory and other simplistic "laws". However I have not a clue how to explain something as apparently simple as how two electrons repel each other! It's all very well saying a virtual photon...
It's a compromise. Higher frequencies could make use of smaller transformers but they are not good for transmission, too much power is radiated. 50-60Hz are frequencies at which it was easy to make induction motors back in the 1900's. Europe uses 50Hz, the USA uses 60Hz. There is no good reason...
It's important to remember that the carrier frequency is usually much higher than the modulating signal frequency. If you want to draw an AM signal, first draw the envelope of the unmodulated carrier (which will be two horizontal straight lines at +Vc and -Vc). Then draw the modulating signal on...
The wavelength of a traveling wave in a dielectric filled waveguide will be reduced for a given frequency because its velocity will be lower. The wavelength of a resonant cavity (assuming the same mode) will stay the same. That is determined by the boundary conditions (i.e. the shape of the...