<div>First post here... I'm a total noob, so apologies if this has been covered to death. I tried and couldn't find that much using the search engine.</div><div></div><div>First off, I've got zero experience with RC planes. I've always loved planes and aerospace though and am planning to learn to fly RC. I know all you pros out there can give me some good advice and I've already learned so much by lurking here. I really appreciate any help and advice you guys can give me. </div><div></div><div>A little background and some rambling on my project idea first, or you can skip right to the questions if reading excited noob rambling isn't your thing...</div><div></div><div></div><div>What got me going was seeing how cheap everything has gotten. I do some electronics work and I got hooked learning about autopilots and how cheap GPS, IMUs, gyros, etc. have become. FPV and photography also seem fun to play with.</div><div></div><div>I plan to start with an electric trainer like the airfield sky trainer RTF. I'd love to build my own, but the package deals seem pretty good vs. buying all the parts, and I'd like to design my own from scratch (based on other's designs, of course) when I do.</div><div></div><div>I was pretty disappointed in the controller options out there. Many are really expensive, and most of the cheap ones are 2.4 ghz or only have a few channels. I don't think 2.4 ghz is a good band to use. It's really crowded and noisy with the millions of WiFi devices, microwaves, cordless phones, etc. out there (at least in my small town). I also don't like the LOS issues and limited range as I'm in a fairly hilly area. It's also a problem if you want to use cheap 2.4g cameras, and one idea I also would like to try is putting a WiFi module on the plane for downloading hi-def video when access points are in range.</div><div></div><div>Given my interest in UAVs, FPV, photography, autopilots, long range, etc., and my electronics/programming experience I started looking at other transmitter options. I found the OpenLRS project, which is based on a Hope RF module, which uses a Silicon Labs radio chip. SiLabs now makes a SoC (system on a chip) radio that combines a radio on a chip and a microcontroller. The OpenLRS uses a RF module and a separate microcontroller. The specs are... 433 MHz, 100 mW TX, with an amazing -121 dB receive sensitivity, all combined with a really low current draw.</div><div></div><div>Anyways, I came up with the idea of using the Si1000 (or 1001, 1010, or 1011) SoC radio as a TX/RX combo. Hopefully, using a SoC radio and a simple serial PWM controller IC (probably a 16ch TLC5940) I could build a transmitter and receiver for super cheap with long range and low current draw. By using a PWM controller IC to control the servos I'm hoping to get better PWM performance, a ton of channels (up to 16!), and off load any clumsy software based PWM to a dedicated IC. This should save a lot of clock cycles, which I hope to use to see how many autopilot, flight stabilization, fail-safes, etc. I can cram onto a single chip. Most of my experience is with AVR though, so I really don't know how much clock I'll have to spare.</div><div></div><div>I'll be happy if I can just build a 433 MHz, 100 mW TX/RX combo with lots of channels and the ability to communicate with an autopilot board and/or relay sensor and telemetry data. The ultimate would be to squeeze every feature ever dreamt of onto a single chip mounted onto a postage stamp sized board along with one other IC, and have the whole thing run for days on a AAA battery. ... It sounds like a pipe dream to me too, but if I'm going to layout a board and go through all the hassle of SMT work, programming the controller, and working out all the bugs... I figure I better design this thing from the ground up for ultimate cheapness, features, and performance. I'll also be getting almost all the components for free by ordering samples from the semiconducter companies, and I don't believe in bull****ting them for engineering samples just to build existing designs for cheap. If my project works out it will be a new open source design for them to add as a reference design or application note if they want and I'll raise the money to do a small production run of boards if there is much interest.</div><div></div><div></div><div>A few questions that hopefully have simple answers to anyone with real world experience...</div><div></div><div>#1. Why do all the controllers I see use the two stick design? What advantage is this over a single stick, joystick-style controller?</div><div></div><div>I get the generals about the control functions of each stick, but it's been burning me trying to figure out why we wouldn't use a regular computer-style joystick, or at least have that option on the market. Those little sticks seem potentially hard to use. I imagine them as touchy and sensitive, with their short length making the same degree of motion much smaller at the end than if you had a longer stick to hang on to. Most fly-by-wire and old planes going back to the Wright brother's flier seem to use single sticks. I've got an old Microsoft Sidewinder 3D Pro laying around I was thinking of trying to use. It's got 4 buttons on the stick, 4 on the base, a throttle, 8-way hat switch, and the entire stick twists left and right for rudder control. That would give it a possible 20 channels of control. Obviously you don't need that many, but it would allow for configuration. I would think something like this (or even using foot petals) would be nice for FPV, and a more like a full size plane's controls. Pic and review: http://www.sunstorm.com/ceo/reviews/3dpro.htm</div><div></div><div>I ask also because I want to get my controller project going as easily as possible and it would be cheapier and easier to have my TX linked to a laptop with a controller plugged into the laptop. Otherwise I'd have to work out a hardware/software implementation directly on the TX board. If this doesn't sound like it would work well I could also use one of those regular RC-looking controllers that they sell for RC flight sims.</div><div></div><div>#2. How to all the features on those fancy controllers work, and which ones are most important?</div><div></div><div>I see the fancy ones are programmable with lots of settings. What does all of that do for you? I understand the trim and having saved settings for trim, range, and deadzone. I'm wondering about the other features and which ones are important or most usefull.</div><div></div><div>#3. What sensors are most important on a plane?</div><div></div><div>I'd like to integrate a few of the very most important ones right on the RX board. Battery voltage seems like the most important for electric and it would be logical for the RX to know how much power it has left even on gas models. Other sensors I can think of that might be good to have directly on the RX board would be current, RPM, and temp. Other sensors might be best for an additional autopilot or sensor board, but I'm curious what else might be important enough to have on the RX board. I'm trying to figure out exactly how to interface everything without putting too much unneeded stuff on the RX board or making the sensor units too complicated either. Mainly, what would you want if you just wanted to replace a standard setup, but could cheaply add a couple things that most people would want even if they didn't want to get too fancy.</div><div></div><div>#4. What are typical electronics payload weights for RC planes?</div><div></div><div>I know that covers everything from tiny little planes to huge scale planes, but I'm trying to get a feel for what is reasonable. I'm planning to start with an AirField RC 55" Sky Trainer v4 (http://www.nitroplanes.com/93a300-14...d-rtf-24g.html). I figure that plane can carry quite a bit and even has flaps. If anyone can guesstimate what that plane can carry it would be very helpfull. I'd also like to figure out what a more normal weight for smaller planes would be. The first version of my controller might be fairly large and I'm trying to figure out if I can/should throw in an extra battery (2x) for the motor and a separate one for the RX unit (total 3x, smaller batt. for RX though). I'd also like to throw in an android phone @ about 4.58 oz (130 g), for GPS logging.</div><div></div><div>#5. Are there any specific problems with larger antennas?</div><div></div><div>At 433 MHz, a quarter-wave antenna would be about 6.5 inches, half-wave 13 inches. Does a small rod this long pose any significant problems? There are plenty of shorter designs</div><div></div><div>#6. What ranges are people achieving with their controllers?</div><div></div><div>I'm curious about frequency vs mW power vs range. Posts on the OpenLRS forum suggest that 100mW @ 433 MHz should be able to get 1.5 miles (2500 meters) LOS on the ground. I've also seen that there are 1W 2.4g boosters out there. I'm trying to figure out if 100mW is going to be enough power of if I should integrate a RF amp chip on the TX board also. 1W sounds like a nice round number and is probably the most you can legally transmit in the US on the ISM band.</div><div></div><div>#7. How common is it to lose control of a plane due to signal loss, and what happens when it happens?</div><div></div><div>Curious how often this happens and what people do. Do you jump in a car and chase it down? Does that usually work or do planes just fly off into the sunset?</div><div></div><div></div><div>I realize there are legal issues with the FAA about operating out of visual range, and I'm not suggesting I plan to break these rules. But it seems like UAV regs are in flux and better cheap controllers could only make the FAA more likely to loosen regs in the future.</div>