The World’s First Hands-Free Mode Zero System!

Okay, first off, what’s a Mode 0 system?  I’m sure most people on here are familiar with Mode II, which is the standard here in the States, and Mode I which is the standard, well, just about everywhere else. Actually, I’m surprised Mode I isn’t more popular here as I, and I’m sure a lot of others, first learned with two channel systems that had pitch on the left stick and direction on the right.  So you’d think we would follow suit on Mode I. But as everyone knows, the two favorite pastimes in America are:

1) Baseball, and
2) Virulently rejecting the Metric system.

So, naturally we have to be different.  But, what is Mode 0?  If you’re an RC history buff, you know many of the first commercial radio systems were single channel using a pushbutton on your transmitter and a rubber band driven escapement.  This is my Ecktronics transmitter from 1962.  It’s a few months older than I am.





Initially there was:
Push and hold the button once, right rudder.
Push and hold the button again, left rudder.
Keep pushing the button and the rudder alternates until the rubber band winds down.  Hopefully after the model is back on the ground.

Then, smart people developed the system where you push and hold the button and you get right rudder.  Push twice and hold and you get left rudder.  You didn’t have to go through the rudder going the wrong way before you get the direction you want.  

Want elevator?  Someone came up with push and hold once, right.  Push twice and hold for left.  Push three times and hold and you get a kick-up elevator.  What more could you expect out of one button?

Throttle maybe?  Someone much smarter than me came up with the three above push and hold for direction, but with a system where you start with low throttle, tap the button and it goes to mid throttle, and tapping a third time gives full throttle!  Genius!!!  Tapping again drops back down to mid throttle, and once more for low.

By this time multiple reed systems were available, and the first proportional systems were showing up.  Today, only history buffs and masochists like me still do pushbutton single channel.  But we of the RC purist ilk refer to single channel pushbutton as Mode 0.  It’s not that big on this side of the pond, but seems to be very big in the Mother Country.

Okay.  So endeth the history lesson**.  Well, what is this thread about?  Ladies and Gentlemen, I present to you the Batjac Aerowerkes Hands-Free Mode 0 Radio System!!!





When I first started thinking about a system where I didn’t want to have to hold a large box just to push one little button, I figured I could make a transmitter that I could strap to my arm and hold a simple plunger in my hand to fly with.  I thought something that I could strap to my bicep like a jogger’s MP3 player and run a lead down to a pickle that I could hold in the corresponding hand.  The idea was feasible, and I made up the prototype.  But then I thought, “Why hold anything at all?  What do I need to hold something in my hand for?  Either hand?  What if I want to hold a Coke in one hand and a hotdog in the other while I’m flying at a fun-fly?”  Thus became the system you see above.

The heart of this system is a circuit board developed by an engineer and Old-Tyme RC enthusiast in England named Phil Green.  Phil has made many great projects and sells encoder boards that you can hook up to your modern radio transmitter or receiver to emulate the old single channel radios.  Check out his website (Single Channel UK).  I based my project on his transmitter encoder board and a FrSky 2.4GHz conversion module.  You know, the ones you use to convert your old 72Mhz radio to 2.4GHz radios.





I first took that FrSky  module and cut back every wire I could and soldered them directly to the encoder board to make as small of a transmitter unit as I could.  I then soldered short leads to a 9V battery holder.  I made up a box just big enough to stuff everything into, and attached a battery box.  But, what to mount it on to attach to my arm?  Looking around the room, I noticed my PVC bow in the corner and thought, “Ah-HA!!”  That wrist protector would be perfect for a transmitter mount.  It’s even in a color I like.  So, I dug into my Monokote stash and found a roll that is a great color match with the wrist protector.

I covered the transmitter box and then hot-glued it to the wrist protector.  For the pushbutton input I made a jack in the corner of the control box that a standard servo lead would plug into.  I dug out a microswitch and then brain stormed how to make it hands-free.

Yeah!  That’s the ticket!  I pulled out a celluloid banjo fingerpick and heated it up so it would fit nicely around my index finger.  I soldered the microswitch to a servo lead and glued it down.  Perfect!






But what if the finger switch failed or the lead pulled out?  Okay, back to the drawing board.  Is there room for a micro switch in the box?  Yup!  So I cut a hole in the box and mounted a switch in parallel with the finger switch so I can control the plane from the box.






What if someone else wants to try flying Mode 0?  After all, all good transmitters have a trainer switch.  Time to revisit my original premise.  A pushbutton on a long lead.  I can hand the pickle to someone standing next to me so they can try flying single channel, and if they lose it I can take control and use the button on the side of the box to recover.






And ready for flight:






More later…

The SAE Mark


** Yes, I know Cox sold rudder only planes and gliders that used push buttons.  But they used TWO buttons, so they don’t count.  So there!