Current and voltage meter in the mail today!

 

This is what I got in the mail today. I ordered it from GoodLuckBuy and it was shipped out 10 days ago. This still means that the average time to delivery from China is about 9-10 days depending on holidays I suppose.

The little device in the middle gets hooked up and man-in-the-middles the power coming from the battery and tells the flight controller how much juice it has left. There is an excellent integration instruction at ArduCopters wiki but this is roughly how its meant to work shown in the picture to the right. There are some settings in Mission Planner that allows the flight controller to conduct an emergency landing if the voltage falls too low. Remember that I previously written that I've set my ESC's to cut power at 3V in order to spare the batterys health. This means that I should make an emergency landing prior to that. Other than an emergency landing is also to order the flight controller to RTL. However, we all know how that ended last time..

Talking about failing RTL's, I yesterday think I've got a clue why the GPS has been acting strange lately. By accident, I looked at the quad's heading according to the flight controller and it was 90 degrees wrong. This means that I've mounted the GPS 90 degrees wrong which makes the flight controller do things the wrong way.

Another update is that I received an e-mail this morning from the author of MegaPirateNG with a link to MPNG-3.0.1-R2 :). I still haven't downloaded the code but I sure will within the next few days.

I've also got another package in the mail about a week ago, which I still haven't written about. I will do so in a separate blog post due to its large content. I also have a few surprise upgrades so stay tuned ;)

 

MegaPirateNG 3.0.1 is out!

Sounds like a shout from the grave but this is something that I didn't expect.
Today I read on some forum that MegaPirateNG 3.0.1 is out. It also has a brand new official site. The site claims that they have shipped the new code to those who have donated at least $10 to the project. The rest of the world has to wait until late September. Therefore, today, I've donated $10 and should hopefully receive an e-mail containing a golden link. I did that also because I want to support the continuation of MPNG.

As soon as I get the link, I'll make sure to try it out and report back on the look and feel.

Link to MPNG official site: http://www.megapirateng.com

Radio telemetry ordered

A few days ago, I decided that it was time to order a radio telemetry set. I went for the set from GoodLuckBuy.com (got to love that name) for roughly $36. However, today when I investigated into why I hadn't received any package tracking information, I discovered that the package hadn't event been shipped out. Slightly disappointing as the page does not clam that the items are out of stock. The support chat however informed me that the items were in fact out of stock. Big minus for that site.

Anyhow. Not loosing fate, I decided to order yet another item, which I found in the new arrivals at DealExtreme as well but for a higher price. This is a current and voltage sensor that is way cheaper than shiny once at Sparkfun.com. It looks the same and has the same specifications but for a lower price, $14. It's used to report how much juice is left in the battery back to the MultiWii flight controller, which may take action if the capacity is going low. Actions such as RTL or land. We'll see how this goes but the support attendee informed me that the item was in fact in stock. At least one item was..

MegapirateNG vs. MultiWii

I've been reading up on forums on the progress of future releases for the MegaPirateNG code base. To my astonishment I soon found out that the main maintainer behind MegaPirateNG left the project to join the ArduPilot team. This means that currently MegaPirateNG isn't developed. A small project fork all tho seem to have been done by some enthusiasts. This is called megapirateng-add-ons ( https://code.google.com/p/megapirateng-add-ons/ ) and is a beta into MegaPirateNG 2.9.1. Some folks claim its superb while some clam it has serious bugs. Others tell to look into the MultiWii code base instead.

Today I tried out the MultiWii 2.2 code, which is the latest in it's branch. From the first look and feel, it feels like the quad is handling a lot more stable. This is before touching any PID parameter configurations. I've done some level flights and it feels really stable. I haven't figured out if it's possible to configure the controller to decelerate the quad on releasing any of the pitch or roll controls, which MegaPirate did by default. That behavior is very helpful for beginners.

The guide I used to get going with MultiWii can be obtained from this forum thread:
http://www.multi-rotor.co.uk/index.php?topic=411.0

This is my current configuration and a look at the MultiWii configuration program.

One detail I found very useful is the fully configurable mode selector. This can be used to combine several features to build your own flight modes instead of having to use any vendor supplied modes.

My configuration states that not using AUX1 should result in a level (angle) flight. Using AUX1, level, barometer to hold altitude, magnetometer to hold heading and GPS to hold position should be used. AUX3 is used in a similar fashion but invoking GPS return to home instead.

It's thereby possible to combine any of these features in any desired way. Further explanation can be obtained at the MultiWii wiki page.

Stay tuned for more information as I go along. I will try to test out the GPS return to home function rather soon.

Another one bites the dust

 

There has been a few days since I last wrote. To that, I can only say: laptop + morning coffee = less blogging and even less field testing of quad.

Today was however the first time since the resurrection that I've done some serious testing. I wanted to try out the RTL (return to launch) function that went AWOL last time I tried.

The first thing that happened today once I fired up the quad and was lifting off was that after 30 meters or so, one of the blades of the front left propeller broke off. I didn't realize this at first but what happened was that I heard a ill sounding noise as if something broke followed by a ill sounding motor engine. The quad then slowly started banking towards left and at that point, I couldn't stop it from flying further to the left. I made a controlled crash landing as I couldn't stabilize the quad. Once I located it again I quickly realized why it behaved as it did; it had close to no lifting power on the left side and therefore, I couldn't stop the motion towards left.

This is one of the 8x45 propellers I recently bought and from the breaking point it looks like it might had been delivered with a defect. I am no expert in this field but you can examine the picture for your self. Anyhow, these are cheap propellers and I guess I buy more as they may break. The positive outcome from this accident is that I now know that a failing propeller isn't an instant fatal crash but very recoverable.

I've considered buying these carbon fiber propellers instead of the plastic propellers I've been using until now but they are fairly pricy and I think I need more practice and less close calls to fund these. Carbon fiber propellers won't take any small nudges without splintering into pieces nor will the plastic once but the plastic once are six times cheaper..

X550 resurrected

Done a few test flights with the X550 after replacing broken parts and it seem to fly as it should. Haven't tried anything GPS related yet but it spins like a cat and flies like a bird.

This is a short video from one of the first trial flights. The camera vibrates like crazy but you can still make something out after using the stabilizing enhancements thanks to YouTube. Guess I'll need to do something about this in the future.

RIP zippy

 

The last casualty of the crash is the battery. I tried all last night to revive it using all sorts of Jedi mind tricks to the charger according to instructions. The force wasn't with me this time and as I feared it felt it might catch fire due to the heat and the fact that it started expanding, I stopped my attempts. This must be the single most expensive loss of this crash but still nothing compared to rebuilding the whole quad.

Whats broken

 

Today's casualties:

• Bottom right boom was bent
• Propellers spent as you can see
• One motor with strange sounds
• Ultrasonic range finder is MIA
• Few nuts and buts are spent

I found all electronics including flight controller, GPS, radio and ESC's to seem to work as usual.

Next thing I'll buy is the telemetry radio :).

The X550 has returned!

Today I found the phone with the number set up for people whom might have found my quad with a new message :). A local farmer had found it in the woods to the west of the high way where I was flying eastwards of. In other words, it flew over 300 meters away from where I have been looking for it.

 

I still haven't had the time to assess any damages but from what I can see, the frame is slightly bent in a couple of places and propellers are broken. Other than that will be in my next post.  

Shoestring FPV kit

Something I haven't written about yet is FPV on a shoestring budget. The main reason why I haven't is that I can't currently afford it. However, here is a suggestion that definitely goes on my wishlist for Christmas.

First item on the board is a camera. I've previously written about the key chain 808 DVR for less than $7 that does OK recording. But for FPV you need something else. Now there is a version 2 of the 808 key chain camera that can do just that. The kit also includes a USB to video out cable that can be attached to any video transmitter to enable FPV. The improved camera is fitted with a 120 degree wide angle lens instead of the crappy narrow angle lens on the cheaper 808. This camera goes for $39 at eletoponline365's eBay shop.



For transmitter, I'd choose something with a low frequency again as with the controller radio. That is to gain as long range as possible. I found this kit at Banggood featuring a 1.2GHz transmitter. Other FPV kits regularly feature 5.8GHz. The problem with 5.8GHz is that you need clear sight between the transmitter and receiver. With a 1.2GHz it can work with some obstacles. This transmitter and receiver kit goes for $56 at Banggood.





A OSD device is something some people prefer as it applies a virtual head up display on the FPV image. The OSD device is hooked between the camera and radio transmitter hijacking the image and applying OSD using data from the flight controller. An OSD usually applies information such as: virtual horizon, altitude, air speed, heading, direction and range to "home". Home as applied for RTL. This OSD goes for $27 at Banggood.

You probably need additional wiring to connect the kit together but these are the basic devices needed for FPV.

Summarizing purcuses:

• $39 - 808 #16 v2 key chain camera
• $56 - FPV radio
• $27 - OSD device

In total, $122.

More electronics

Doing some further research found that HobbyKing also features the 433MHz telemetry kit I found at GLB (GoodLuckBuy.com). Link to mentioned kit.

However, this kit comes with antennas that are optimized for 900MHz rather than 433MHz according to comments. Seem to be the same transmitter and receiver anyhow so if I choose to buy these, it will be from GLB.

Further browsing, I found a flight controller resembling the MultiWii/MegaPirate controller I previously used. This controller claims to be version 3 and seem to have improvements in the way the serial ports are made. Version 2 had three serial ports in the same physical port when this controller has separate physical ports for each serial port. I can't see any other differences looking at chip specifications.

MultiWii & MegaPirate v2.0

MWC Mega 3.0

If I can find that these are compatible, I'd rather choose the version 3 as soldering small wires are a pain when breaking out the serial ports.