Reddit mentions of Spektrum 9645 DSMX Remote Receiver

I never thought the flybrix was worth it...it's a gimick in my mind...

Look into the Eachine QX90...

http://www.banggood.com/Tiny-QX90-90mm-Micro-FPV-Racing-Quadcopter-BNF-Based-On-F3-Flight-Controller-FrSKY-Taranis-X9D-p-1069614.html?utm_source=google&utm_medium=cpc&utm_content=allison&utm_campaign=Smlrfpv-ds-58fpv&gclid=CMW10MXBrc8CFYpZhgodeW8M1A

For $55 bucks you not only get a pretty fun brushed quad, it comes with FPV too (you'll still need a video reciever for the video, but it will work the same if you don't use the FPV unit)

You will also need a Transmitter, something like a Devo7e will work...

http://www.banggood.com/Wholesale-Walkera-Devo-7E-7CH-Transmitter-Mode-2-Without-Receiver-p-48117.html

Thats another 60 bucks...but it will bring more joy to flying than using a shitty bluetooth app...

Since the QX90 doesn't come with a reciever you'll need one...

https://www.amazon.com/Spektrum-9645-DSMX-Remote-Receiver/dp/B004M12GY6

Thats 34 bucks but I think you can find it cheaper...

I mean for a little more than the cost of the flybrix you get something that will be 100x more enjoyable to fly and not only that if you wanna spend a bit more on some FPV goggles you'll have an FPV miniquad too...So much more bang and fun for the buck...

Or you can look into the Induxtrix FPV....not released or shipped yet, but it's all the rage for indoor fun...

Your tech director seems like he thinks he's a "know it all" kinda guy...but he's pretty wrong if he thinks the flybrix is cheapiest and most robust...

Also, I know you want the ability to control via iOS/Bluetooth, but honestly you really don't. It's pretty terrible to fly anything via a phone and it teaches you bad habits. why not just go with proper equipment and not teach your students bad habits when it comes down to it? it's not much more expensive, and in the end it's gonna be a lot cheaper..as you'll still be able to use a proper Transmitter if you decide to upgrade the quads pretty much forever..with the flybrix you are kinda stuck with the app, and what happens when they stop support for the app?

Edit: the ready to fly inductrix is even cheaper and if you wanted you can get a proper transmitter for less than the flybrix...

Blade Inductrix RTF Ultra Micro Drone with Safe Technology https://www.amazon.com/dp/B011UDQYSC/ref=cm_sw_r_other_apa_3Mv6xbTVS308F

Just look up Tiny Woop FPV and you can see how much fun and more safe it is to fly than the flybrix...i mean you weren't looking for fpv flying but it's till a cheap option if you want to move to fpv too..

Edit2: also you should know that brushed motors for these kinds of quads have a finite lifespan before the brushes wear out and you need to replace the motors...the lifespan is generally around 5hrs of use... So yeah take that into account too...

> Does it matter brand which receiver that I use?

No

> Like are some more compatible than others?

yes, for example you can use the spektrum satellite receiver stand alone with an arduino. The arduino can decode the serial data stream from it.

To use a normal receiver you can either connect every single channel to the arduino (wouldn't recommend) or generate a PPM signal from all channels with something like this: http://store.3drobotics.com/products/ppm-encoder

> Can I control two Arduino Mega with the same Receiver (AR610)?

sure, but keep in mind that you won't get more than the 6 channels your receiver is capable of