I wondered why i have never seen anyone making music with a siren so i had to try it myself.
It was started when i browsed thingiverse and found a nice little siren model and i had all the parts i needed around.

The interface is based on an arduino micro as a midi interface to generate a ppm signal to use with hobby escs based on incoming notes.
If the esc and motor respond quickly enough and hold the speed well it can be used as a (probably terrible) instrument.
I was pretty surprised how well it actually workded and expected it to be much worse.
The speed is not really regulated other than by the calibrated esc and a fixed voltage source and the spin up and down time depends on the inertia of the rotor and how good the esc can brake.
Fast quadcopter escs and a strong motor are preferred for this.
Some escs offer closed loop speed controlling which would be even better.
I have used a cheap racerstar lite 20A esc running blheli and a spare 2204 multistar elite 2300kv motor.

This is my first real quadcopter build.

It is based on the Diatone 250 frame, some Multistar elite 2204 2300kv motors and the naze32 flight controller.

The Naze32 rev5 does not work with sbus without an additional inverter so i first tried to just use pwm.

Even without flying i noticed an annoying delay in the throttle response so i tried to use sbus anyways and bypassed the inverter in my x8r.

I will still have to change the flight controller later as i want to use s.port telemetry, which won’t work with the naze32 rev5.

To save a bit weight it should also be a good idea to clean the wiring and switch to the smaller frsky x4r receiver.

Pretty much finished now:Even with stock pids it hovers fine:

Some years ago i loved smartpropoplus, a software that lets you use any rc remote with trainer port on you soundcard to emulate a windows gamecontroller.

While playing around with rtl-sdr i found out that my receiver can receive the 35mhz band and tried to capture some ppm data from a 35.11mhz Hitec Optic 6 remote and the results were great:

I decided to direct the fm decoded signal from sdrsharp via VB-Cable into smartpropoplus to check if it can be decoded and it worked.

The next time i used a raspberry pi to receive the signal and direct it via rtl_fm and aplay into a soundcard input the same way the remote would be connected with a trainer cable.

The latency is pretty high because of rtl-sdr but this method works great with any remote control and it is not longer limited by a trainer port and you get some pretty good range.

It makes no difference in the delay if rtl_fm or sdrsharp is used but  rtl_fm is of course better for any „real“ use.

Just setting up this blog.

More stuff is coming soon.