aircraft radios and current projects

[RFguy]

Currently in my system I have a few aviation projects on the go.

1) I suspended the radio out of my schedule in March due to other commitments, and that I was feeling a bit of feature creep, and this was turning it from a simple radio into  to a complex design with multiple parts, and such things cost alot of time and this isnt a high value product. So this week I've got back to it and cut it down a bit- UHF CB is now not simultaneous (you can switch to it) - it was putting too many screws  and complexity on the aviation band design to have it do both simultaneously  and stay simple. also, I wont have it receiving ADSB anymore, more stuff too complex,. if this is going to get out the door, it needs to be more basic- still has the 4 simultaneous receivers and 10W TX /1W switchable TX power radio, and intercom etc.  Also, I was planning to use an existing radio platform I have which is a bit too big to fit into a small panel hole, like Trig, Microair etc, so I was going to run it as two boxes. But two boxes (panel and main unit together with cables, connectors, extra microprocessor for the panel display ) is another complexity , so that goes.  which has meant going smaller on the PCB. The upshot of that is that this triggers a design overhaul and it will now all go into a panel hole, which simplifies everything. 

So, on with that show !

 

2) "anywire interface" . there's a big problem with getting a new radio/intercom installed these days, is gettign someone to do it.... maybe we can skip that problem----. It is quite feasible to make a box that you connect every wire, but it doesnt matter what wire is what,  IE you just connect the wires in no order and the box figures it out for connection to radios on a standard harness for that radio.  IE doesnt matter where you connect grounds, mic, ptts etc nothing. 

 

3) I'm making some Jabiru targeted  alternator regulators.  the big plus, they'll generate useful charge from 600 RPM upwards, instead of 1500 RPM. and they wont overcharge batteries etc, and can be told about the chemistry.  They will run warm instead of red hot (at full load) ,  and will have no chance of going short (which generates a stator fire) ....

4) Collision warning/ aircraft proximity warning. I built one. Has triple GPS and triple barometer so it doesnt care if it has a poor view of the sky- (skyecho can generate up to 300m error if it doesnt get a good view of the sky. .  has basic adsb receiver also. 

apart from an audio output  (into aux, or a mixing port so it can go in series with the intercom/ headset with failsafe relay bypass) , the $64 question is how do you display it ? Do you send it out like the skyecho talkes to the tablet, or have some custom screen ?

 

anyway, that's what is cooking.

glen

Edited July 17 by RFguy

[BrendAn]

number 2 sounds cool. does a computer route the signals to the correct wires automatically.  thats pretty amazing

[RFguy]

comes from the demonstrated need for people to get their radios and intercoms fixed and installed, with very few  competent to do it....

[RFguy]

Brendan,  yeah there are quite a few parts on the PCB to do this, but the incremental cost of parts on a PCB being machine placed is very low. There are two ways of doing it, You either make every terminal capable of any function, and route using transistors to the 'output' pins (IE the known interface like a connector for a Tig or garmin or whatever) , or a matrix crosspoint switcher of miniature relays is used- very reliable because the relays which are rated for millions of cycles only get a cycle every time the plane is powered up, it it might get 10,000 cycles in its life.... With the relay crosspoint switcher, it still needs to route the signals from some processing to get audio levels right , PTT  etc levels translated .  but its all low tech.

 

While there's alot of parts on said board , its still cheaper and more so, probably shorter time than waiting for a rare avionics person to do it (properly) . 

 

The relay crosspoint switcher- if it needs to switch anything to anything needs Nsquared crosspoints(relays) . These are solid state relays, about 3mmx3mm and less than 30c  each .

 

The universal terminal method, where any terminal can function as a audio input, output, ptt, or ground, needs a bit more design finesse but probable more adaptable especially if you get up to 4 intercom places OR multiple AUX inputs ( multiple radios, efis warnings, ipod , etc)

 

The user wires up every terminal (with impunity)  and a fairly basic algorithm goes out and discovers  what it is on the end of everywire.  that's fairly simple electronics, there's just alot of it for alot of pins..... .probably worth a patent.

 

Someone still has to make up a cable to go from the box to whatever the radio you are using is , but that's a straight through  cable, nothing special, just pin to pin. It's possible that a standard (one for all) cable could be used out of the box to a  radio and use a printed circuit board  connector to plug directly into the radio,  (the traces on the PCB are such for the radio) so there is NO non standard cables or wires.

 

Said box would/could  also function as a intercom etc, since it is doing signal processing and routing. 

 

-glen  

Edited July 17 by RFguy