The PCB

Hey All,

As Liam has said, I have spent a bunch of time working on the PCB. Shortly after starting version 1, I realised that the PIC 32 was not only overkill, but programming it, and the PCB were going to be over my head. So I convinced Liam to let us use a PIC18F series microcontroller instead.



On this board, I've made connections for a large number of peripherals. We have an LCD, the Digi Xstream module, Accelerometer, Gyroscope, GPS, RPM Sensor, Sonar Range Finder, 5 servo ports, and 1 ESC port. There are 4 status LEDs, two for the radio module, and two for the MCU. I figure I can program what I want the two MCU ones to do, but at this stage it will show boot, all okay, and error.

The power supply features two linear regulators from microchip, one for 1.5A @5v, and one for 0.5A @ 3.3v.

The main controller is the PIC18F46J11, and the fail safe is the PIC18F26J11 (Which I am certain the package is modeled wrong, so I plan to check that one out...)

I'm sure someone with more experience would have made a nicer and more compact layout, but I am new to all of this :-). This is the most complex board I have ever routed, and it was great to be able to make it two layer. Previously, I have been able to make two layer boards, but all of the via had to have a wire soldered to both sides, and there was no plated through holes.


Until next time...

Dan

Control Board PCB Circuit

Not really my place to post this up, but since its been a while since the last post, something needs to be put up!

Designed by Dan over the last week, this is the Rev2 board and it doesn't feature a PIC32, but a MCU from the PIC18F family.  It will be a double sided PCB possibly made at Seeed studio and will have a few made.  From memory 10 boards at $4USD per board, exc freight to New Zealand.  I will leave Dan to explain the features of his exciting new board :P

What have I been doing?  Not much to show.  Exams have just finished, and have been quite busy sorting out other stuff.  Slow progress is being made on the front of writing a funding proposal, and we have had a private sponsor donate a good sum of money to get us started, you know who you are, thank you very much!

After modification after modification, we have finally agreed on the airframe and what sensors etc we are going to be using.  The airframe is a URSUS made by a Polish company, linky, the website, however, is in Polish (funnily enough) so scroll down a bit and on the right bar should be a google translate box.

No I didn't choose it because of the sexy colour scheme ;)

Two 5000mAh batteries should be enough to keep this bird in the air for a good half hour to an hour at a time.  A spare 2200mAh battery will power the electronics and be a backup for the servos(citation needed).

Shucks - I just realised something we didn't have on the circuit.  Will message Dan about that now..

Stay tuned!!!

Liam

Control Board Schematic

Hey Guys,

I've finished the schematic for the UAV. Possible there are a few bugs in the design, but I'm thinking it is simple enough that they will only be small bugs. Will require plenty of design checking before we go out and buy the PCBs...

The size of the board all depends on the size of the cockpit. We might even go so far as to build a larger PCB pod on the bottom of the craft just so there is enough room...


Cheers,

Dan

Where we are so far... cont.

Hello readers!

Several designs have been looked at, combed over and scrapped.  I even tried to design one, but with the payload that we were designing it for, I didn't have the confidence nor have enough faith in one of my own designs.

I am a pilot in training, and I have several of my own model aircraft, including helicopters and fixed wing. Quite frankly I am an aviation nut.  A funding issue proved to be the downside in my last project, Phantom I.  Bringing Dan into the mix is going to be a challenge, the only flight experience he has was when I got him to download Model Flight Simulator (FMS) and have a go.  I still have to explain the principles of turning to him.

Using my designs, the plane would have to hit 50km/h before it would take off.  Based at an acceleration of 13.31ms^-2 it would take 3.757 seconds to reach takeoff speed - no flaps. It would take 100m of airfield before you would even think of taking the plane off, which was too impractical for Short Takeoff and Landing UAVs for Search and Rescue.

A new design has been decided. Some plans purchased of eBay are in the interwebs, and then we are going to be checking the fuselage spacing so we allocated battery space etc so we can work the electronics all around.  The design is a twin boom FPV (first person video) plane, with a pusher propeller.

The 3 blade propeller is a 10x8 meaning that it is 10 inches in diameter, and in one rotation, if it were a screw going into wood for example, would move 8 inches in the horizontal axis before returning to its original position.

The problem with this aircraft, is that you cannot have it as a taildragger (wheel on the tail, and two wheels up the front) because the prop will hit the ground! I believe I am going to have to by some taildragger landing gear, then move them rearwards and make a custom nose wheel assembly. Gah. Another problem to overcome I guess...

I think that is enough.. so till next time!

Ciao
Liam

Where we are so far...

Hey Guys,

This project has been under design for the past week. Previously, Liam was working on Phantom I. He managed to construct a craft with all of the control servos. The problem came when he realised how much the whole project would actually cost, $300NZD just for the radio modules.

After some discussion with a Brightsparks Mentor, Liam and I teamed up to build Phantom II. A lot of design work has happened already, and I'll make sure to detail what I've worked on. Liam and I are both authors, so I'll let him tell you about his progress. I'll stick to my progress!

We have chosen to use the PIC32MX795F512L as the main platform controller. This was mostly for the reason neither of us know what we actually need, in terms of processing power, to control a UAV. This PIC32 is basically top of the line, and should be more than adequate.

Liam knows more about controlling planes than I do, and so was the main decider when it came to sensors. Our current list is as follows:

• GPS Module with Built In Antenna
• Triple Axis Gyroscope
• Triple Axis Accelerometer
• Ultrasonic Range Finder
• Stall Switch

Then we have the servo allocations:

• 2x Aileron
• 2x Rudder
• Elevator
• 2x Bomb Bay

Then there are two ESCs for the two EDF motors. Making the total PWM control pins 9. I was going to add a spare port in case we decide to add something.

Lastly, we have talked about having a fail safe unit. It needs to be able to control all of the servos, and reboot the main controller. I've drawn an idea for a possible solution, but have not yet thought about the radio. The problem is, even though the fail safe can control the servos, unless it has a radio link, it will be useless. I might have to get the fail safe to pass the radio through itself while constantly looking for a signal from the operator to enable the fail safe. The fail safe will also monitor the main controller, and self-enable if it goes down.

At the moment, we are working on a project proposal so we can apply for funding. This project is going to be really expensive, and the two of us still go to school. Any sponsors will be given a spot in the sponsors tab on the blog, space for stickers on the UAV, and mention in our publicity.


Cheers,

Dan