October 2008 Archives

You probably all wondered why there was so little news in the last weeks. One reason was that I was on holidays. I was off for a week to the Red Sea for diving. The second reason was that everyone was very busy in the last days and weeks.

Since there was a lot of progress, but no time to document it all, I will blog here about it, without going into too much detail.

Our hardware developers were busy all the time and fiddled with the last design changes of the new NG hardware. It includes numerous fixes and extensions! They did smashing work redesigning the hardware 0.20!

In essence it has become a 3 processor system using the LPC2148 as the main processor running the closed-loop control and having a Atmel 644p and a Atmel 168 as peripherial processors for preprocessing and communication purposes.The main CPU no longer does any measurements itself. It uses peripherial processors or external ADCs for that.

Besides 16bit ADC and new filters for the gyros, we included an air pressure sensor and a compass sensor in the new design. We will support ADXR and MLX gyros. The new hardware has 4 (or even 5) UARTs on different processors and will support the ACT DSL protocol on several of them. This will allow arbitrary ACT receivers (SPCM, PPM, 2.4Ghz) to work with the NG. Furthermore the UARTs will support the NMEA GPS protocoll besides the normal shell access and will allow to attach all sorts of NMEA compatible GPS to them.

In the last weeks our hardware developers cleaned up the new design and fixed the last bugs. They generated Gerber files and panelized them with the help of our board producer.

This week we finally were able to start production of our first alpha boards of the new hardware 0.20. If all goes well, we will receive the first prototypes within the next two weeks!

The above shows parts of the Gerber files of the two layer panel for the new hardware 0.20. It consists of a flight control board, a sensor board and four breakout boards for MLX gyros.

When we receive the new boards, the huge work of porting the old 0.10 software and writing new software for the additional processors can start.

Hello everyone!

I'm back from holidays! My girlfriend and I went to Marsa Alam at the Red Sea for a week. Staying at the Oasis Hotel, we visited the Sinaidivers dive center there and went diving for 5 days.

On the first day I've meet Tim, an old friend from Sinaidivers in Sharm el Shaik. He was doing holidays in Marsa Alam before we arrived and afterward helped out in the dive center for the next three weeks.

In the last three days we went two times to Elphinstone, a famous dive cite near Marsa Alam. Elphinstone is a Shaab, meaning an offshore reef near the coast of Marsa Alam just east of the Oasis hotel. It's a difficult dive site with the sea going down to 200m at all sides.

In summer you can find a lot of Tiger sharks there. We hoped to see them, but sadly the season was already over and they left the reef. But we were lucky: In autumn the Oceanic White Tip shark season just began!

We were able to dive two times at the Elphinstone reef, each time reaching the reef by zodiac. Both time we did a marvelous dive at the reef and tried to spot the sharks. The first time we did not find them while diving, but coming back to the zodiac the sharks suddenly showed up!

They like stuff swimming at 5m or even at the surface of the sea. They are very intelligent and they like to investigate stuff swimming in their district. Being already in the zodiac and jumping back into the water, I forgot to bring my cam with me. Luckily Tim had his own cam with him and was able to record a small movie of the shark!

But look for yourself:

Two days later we visited Elphinstone a second time by zodiac. This time we brought 15L tanks with us, giving us approximatly 50bar air more. This allowed us to do a 1h 15min dive!

Since we did not find the sharks on the west side of the reef the first time, we decided to jump in at to north tip and do a drift dive on the whole east side of the reef. Having 15L tanks allowed us to dive the whole length of the reef... it's quite long. We even had enough air to let us drift out into the blue for 15 minutes at the end of the reef!

We did not find the sharks at the east side of the reef the second time either, but having enough air with us we just drifted out into the blue staying at 5m while putting up a surface marker buoy to make sure no zodiac drives over our dive site.

It did not take long and the Oceanic White Tips found us!

At first a big one showed up in front of us, quite far away. We saw it for half a minute or so until it disappeared again into the blue. At the same time Michael, one of the divers accompanying us, spotted a second shark behind our back! The second one was a bit smaller and it seemed to us as if the first, big one tried to sidetrack our attention so that the attack of the second one succeeds! The second one came as near as 3m or so and I was able to shoot some very very nice pictures of him!

Here it comes behind our back:

... just turns at our side:

... decides that we are no lunch:

... and leaves again:

Be sure to notice the Pilot fishes at his side! Both swim behind the fins of the shark! That way they can keep away from its mouth. They do that as soon as they notice that the shark is hungry, to make sure not to become lunch! Furthermore both bust fins are pointed downwards which gives the shark maximum maneuverability when attacking.

Looks like it thought we could be a fine lunch and then decided against it when he was near. We were 5 divers near together so probably we seemed to big to attack to him.

I heard that two weeks ago a girl was not so lucky and an Oceanic White Tip took a bite of her arm while she was trying to get onto the zodiac. That's the most dangerous moment, when the diver is not paying attention and the sharks sees the most perfect prey pattern he's used too: penguins trying to get into an ice floe. But normally nothing happens if the divers are paying attention. One just should keep an eye on them and bang them on the nose if they get uncomfortable near you.

All in all it was a wonderful dive!