…by Trappy; Team BlackSheep.

FPV is a new, super-cool trend emerging from the R/C community that allows us to enjoy the fascination of aviation in ways perviously not thought possible. As always, new innovations or trends collide with traditions. Within TBS, we have the firm belief that one or a series of technological breakthroughs is sufficient to challenge the way we have looked at things in the past. Before cars had lights, it would have been extremely dangerous to drive at night. Now that they do, driving at night is not much different from driving during the day. The majority of people are able to grasp this concept. However, there are others. We shall call them haters.

Pretty much all the criticism we FPV pilots have received from haters over the past few years is based at least in some part on the notion that FPV pilots fly their R/C aircraft where they previously did not fly: Over mountain tops, under bridges, in city parks. R/C aircraft need to remain on R/C fields, be flown within line of sight of the only pilot controlling them, and any kind of proximity to solid objects, be it a statue, house or tree, is to be avoided. Anything else is extremely dangerous, illegal and is to be stopped with every means possible. Or so they say.

Fact of the matter is, UAVs many times larger than anything that any hobbyist has ever flown have been flying over cities, over people, in restricted airspace and beyond visual line of sight for ages. R/C planes many times the size, weight and possibility for damage fly near people all the time. If a 20kg turbine jet loses control it can fly for a few hundred meters before hitting the ground. So why is FPV getting all the heat? The complaints are based on the perception, not in the danger itself. When you show a video of flying directly over a street, the haters are in uproar. When you show the same model from the point of view of a car on the street, nobody cares.

The lack of cognitive ability to change the perception is probably why haters try to keep UAVs limited to old, traditional R/C spaces. Because that is the perception that they are used to. Similar to a control-line pilot 50 years ago complaining about the new wireless control mechanism and demanding a control-line pilot be kept in place due to the potential of danger coming from wirelessly controlled R/C aircraft. Where would R/C be today if these people were part of the majority? Luckily they were not, and they still are not today. Sadly, however, they are backed up by some R/C organizations. R/C organizations are advocating these limitations because, in essence, they are insurance companies. Insurance companies do not like risks, that is why they try to constrain our hobby to match what they have previously assessed (and are making good money on) to be safe.

So what can you do against it? The only way to vote in today’s times is with your wallet. If you think that your R/C organization is not representing your needs well, quit. Send them an e-mail why you quit and tell them once they come to their senses then you will consider joining them again. Ask all your friends to do the same, too. You can still fly with all your R/C buddies just fine, you just need to launch outside the property of the flying field (you can still fly over it as much as you like). You can even support your local club financially by bringing drinks and meat for barbeque. That way you are doing your part to keep the club going, but are making sure that the parent organization is not receiving its share.

Is an R/C magazine writing negatively about certain aspects of FPV without doing their homework properly? Are their views of FPV different than yours? Send an e-mail to the editor and cancel your subscription. Ask all your friends to follow suit. There are plenty of other magazines on the same topic, no need to feed the very same people that are trying to ruin your hobby.

Is a FPV forum censoring information or constantly harassing you as a member because your vision of FPV does not correspond to that of the owners? Stop posting there and ask all your friends to move to a new forum. Why would you donate your time and provide credibility to a project when you do not share the same goal as them?

Together we can start a movement, we can change our hobby for the better, and we can show these haters that we can practice our hobby safely and responsibly. We can force R/C organizations to adapt, or to die like old, stubborn dinosaurs. I am convinced that the number of FPV pilots will one day exceed the number of R/C pilots, just like with control line and R/C. And then they will need to ask us to join OUR club. Until then, let’s give them hell – Team BlackSheep style.

Copied with kind permission.
Source: http://fpvlab.com/forums/showthread.php?1223

 

Due to my special interests in a customized RC transmitter and receiver system I started with reverse engineering of a Corona RP8D1 35MHz receiver.

The RP8D1 is my favourite candidate cause it’s a double superheterodyne receiver, uses a PLL synthesizer and is controller by an AVR ATmega88V.

Interesting fact about the micro-controller:

Corona obviously has been changed the controller type on actual receiver boards. The first receiver I bought in mid 2010 uses the mentioned ATmega88V.
Two newer receiver, bought in January 2011, are using a controller marked “225K01″ with manufacturer “QRG”.

Fact is the PCB layout is 100% identical on both receivers so must be the pin-out of the different controllers!

So the 225K01 is either a clone or some official AVR derivative, already contacted Atmel for details.

Used components, followed by pictures and the controller pin-out:

  • Controller AVR ATmega88V on mid 2010 board
  • Controller QRG 225K01 on 2011 boards
  • Rohm BU2630 Dual PLL
  • Rohm BH4126 Wideband IF Detector
  • Philips SA616DK High Performance Mixer FM IF System

Board top layer:
Corona RP8D1 Top Layer

Board top layer, filter and crystal removed:

RP8D1 Top Layer with filter and crystal removed

A word about the second LED (PLL lock detect) on the RP8D1: The LED will signal the status of the PLL control loop. If the LED lights the PLL is out of sync, that means the synthesizer can not set the receiving frequency correctly. For normal operation the LED shall be always off.

Board bottom layer:
There is a typo in the picture, the controller type is 225K01.

RP8D1 Bottom Layer

The RSSI signal can be picked up for external use easily on one of the resistors instead of removing the filter and wiring to the SA616 pin 5.

Receiver board with AVR ATmega88V controller:

RP8D1 with ATmega88V

Receiver board with QRG 225K01 controller:

RP8D1 with QRG 225K01 controller

Controller pin-out:

Pin Name Function
1 PD3 Bind button input
2 PD4 Bind LED output
3 GND GND
4 VCC VCC 3.3V
5 GND GND
6 VCC VCC 3.3V
7 XTAL1 Crystal 8MHz
8 XTAL2 Crystal 8MHz
9 PD5 Not connected
10 PD6/AIN0 PPM sum signal input
11 PD7/AIN1 DC 1.46V
12 PB0 Channel 1 PPM output
13 PB1 Channel 2 PPM output
14 PB2 Channel 3 PPM output
15 PB3 Channel 4 PPM output
16 PB4 Channel 5 PPM output
17 PB5 Channel 6 PPM output
18 AVCC AVCC 3.26V
19 ADC6 Not connected
20 AREF AREF 3.26V
21 GND GND
22 ADC7 Not connected
23 PC0/ADC0 RSSI signal input
24 PC1/ADC1 PPM signal threshold for analog comparator, level set by ext. voltage divider
25 PC2 PLL CE signal output
26 PC3 PLL DATA signal output
27 PC4 PLL CLK signal output
28 PC5 Not connected
29 PC6 Channel 9 PPM output
30 PD0 Channel 8 PPM output
31 PD1 Channel 7 PPM output
32 PD2 Not connected

-

Unfortunately pin PC6, the RESET input, is used as IO pin, this means the ISP serial interface is disabled and one can’t dump the flash and EEPROM content. (Already tried ;-) ) Therefore only parallel programming is the way to go which is quite complicated due to the MLF package and required number of wiring connections.

Or maybe there is a hidden boot loader, the USART pins are available on the channel sockets, just need to find out how to activate boot mode if exists.

I made a HV programming adapter and tried to dump the flash of the controller. Unfortunately the memory protection fuse is set, so that’s not an option.
The boot reset fuse isn’t set so there is no bootloader installed.

A fact: The QRG 225K01 is definately an ATmega88 since the signature bytes match in AVR-Studio.

Some more work to do. In any case a firmware for the AVR can must be programmed from scratch.

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