First FPV Flight

I’ve talked about FPV (first person view) flights on RC before this on my old blog post. My housemate Tan recently bought a very small and light keychain video camera and we strapped it to a RC plane and took off to the skies. Here’s what happened.

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This is the small keychain camera. Velcro-ed and taped to the front of the plane. This was the first setup and there was a very obvious problem. The camera was right behind the propeller so when the propeller was turning, it interfered with the view.

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This was how it was mounted. RC plane is a Cessna 172. Very light. Perhaps a bit too light to survive the strong winds that we encountered today.

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Pilot for today is Tan.

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Doing a few low passes so we will be seen in the video. This was the closest I could get to the plane as I only had my 28mm wide angle lens with me.

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We landed and changed the mounting of the camera to the side to get a bird’s eye view. This will give us a view similar to ones in Google Earth.

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Weather was pretty hot and windy. The plane was too light so it porpoised when flying, making the video very jerky. A bigger, heavier, more powerful plane is under construction and it should provide for a more steady and exciting (aerobatics) video.

After we went home and discovered that the propeller was affecting the videos, we devised a mount to clear the propeller from the view of the camera.

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It’s basically just 2 foam blocks glued together and velcro-ed to the top of the wing. You might think that this large object will disturb the airflow on the wing, but that wasn’t the case. Or it wasn’t obvious enough to be felt.

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Preparing for a video of flying into the sunset.

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Taxiing for a take-off.

Unfortunately the last flight didn’t go so well. Resulted in a crash with a broken motor mount, which luckily can be easily replaced. It was due to a strong wind blowing the plane sideways right after take-off, causing it to go into a death spiral.

Here are 2 videos from the few flights we made. This was from the first flight:

This was from the 2nd flight at another field:

Below are some screen shots from the fly bys. The plane wasn’t stable enough under strong winds so lower altitudes weren’t attempted.

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Hope to get another plane up in the air soon!

Lamborghini Reventon Dash

I tweeted about this a while ago but I’ll put it here for the record. The Lamborghini Reventon probably has the best digital cluster around. There are 2 modes available.

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This is the more traditional styled design, emulating analog meters that we find in most cars. Easy to read and understand. Instead of using moving needles, the circular scale will get filled up.

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The second mode mimics the cockpit of a fighter jet. And rightfully so because the Reventon itself is designed with fighter jets in mind.

Here’s a video of it in action. There are however some errors in the display in the video. The RPM is supposed to be shown in steps of 10, not 1000:

Here’s another video showing the cluster:

Building such a dash should be quite straightforward given the proper graphics engine. A small computer will be needed to run the graphics software and also accept inputs from the car’s ECU. Modern cars with OBDII ECU interface will be really easy to setup as OBDII readers are very cheap now. Older cars will have to manually tap their analog signals from the ECU.

Unfortunately for me I don’t have a car with an OBDII interface so if I ever want to build something like that I would need to get the inputs from the current dash and convert them to digital for the computer. But seeing how cool it is, it will probably be attempted sometime in the future. Perhaps by salvaging a netbook with a decent screen.

4AGE Blacktop Disassembly

Yesterday was disassemble-your-engine-and-see-if-you-can-put-it-back-together-again day. So that was exactly what we did. Initially we wanted to do remove the cylinder head and change the valve seals but we were missing the tool to open up the head. So we only managed to remove the valve cover and throttle bodies for cleaning.

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With the valve cover removed and throttle body removed. There is a large number of vacuum and fuel hoses to disconnect so it’s wise to label them properly during removal. You can clearly see the camshafts and the cam pulleys from this angle. Those were not disturbed because we lack tools to open up the head.

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Here’s the throttle body removed from the engine block. You can see the throttle cable quadrant near the 2nd throttle intake.

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Because there are 4 throttle bodies each feeding their own cylinder, all must be tuned properly ensure that airflow to each cylinder is balanced. The flat head screw that you see beside the throttle body intake are the bypass screws that are used for tuning. A carburetor balancer is needed to perform the tuning.

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This is the other end of the throttle body assembly. This surface mates with the engine block’s intake side. The grooves running below and to all the openings is the tapping for the manifold absolute pressure (MAP) sensor. The MAP sensor sends manifold pressure to the ECU to calculate how much fuel to inject through the fuel injectors. Not shown here are the fuel injector nozzles and various vacuum tappings.

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The back view of the throttle body assembly. There’s a throttle opener (doughnut shaped object with an actuating rod) and a vacuum switching valve (square shaped object with blue connector) for emission control.

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And this is the idle speed control valve (ISCV) to control the idling speed of the engine. This is attached to the engine block and has a flapper valve inside that regulates flow in the vacuum line.

The reason I opened up the engine was to find the cause of engine oil consumption. During hard acceleration, white smoke can be seen coming from the exhaust and that is an indication of engine oil burning in the cylinders. A normal engine burns oil too, but at a very slow rate hence smoke will not visible from the exhaust. With the throttle body out, I can see the valves:

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Now it is very obvious from this picture that a substantial amount of oil has seeped through the valve seals and are now coating the top of the valve. Once the valve opens, the oil will go into the cylinder together with the mixture of fuel and air, thus creating the white smoke at the exhaust. A top overhaul should solve this problem. But since oil consumption is still not very high, I might just put it off till next time.

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The oil on the valve comes from here. The oil that is used to lubricate the cam lobes and valves have seeped through defective valve seals and entered the combustion chamber.

Soon it was getting late and dark so we decided to put everything back together again. The throttle body assembly was cleaned with diesel. Surprisingly the throttle body was quite clean. Just grime on the outside. Also readjusted the throttle cable to reduce the slack.

With everything reinstalled and triple checked, the ignition key was turned. The engine cranked for a while but didn’t start. It took a lot more cranking before it finally started. Must be due to the lack of fuel in the fuel manifold since we drained it when we removed the throttle body. Engine idled properly, no unusual smoke or sounds. Went for a drive and everything was fine.

Next up, probably going to remove the head once I get the proper tool for it and get the valve seals changed and to examine the pistons and valve seats.

External Bluetooth GPS on the iPad

The Apple iPad has a large screen which makes it very useful for displaying maps and navigation information. Unfortunately I own the non-3G version which doesn’t come with the built-in GPS receiver. However I do have an external bluetooth GPS unit which I keep in the car. I’m currrently using that to supply GPS information to Garmin that’s running on my CarPC. I have one that’s similar to the one sold by Amazon:

The next problem is with the iPad’s bluetooth. Apple users will no doubt know that Apple locks everything down. You can’t even transfer files over bluetooth without jailbreaking and hacking it, let alone pair a bluetooth GPS to it. So to continue from here onwards, you’ll need to jailbreak your iPad. Spirit JailBreak does the job perfectly if you have firmware version 3.2 and below.

Software required:

  1. Spirit JailBreak
  2. roqyBT
  3. MotionX GPS HD or MotionX GPS Drive HD

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Next, using Cydia, you’ll need to download roqyBT (pronounced rocky bluetooth). The source is from http://apt.modmyi.com which you should already have in Cydia. Once you have successfully installed roqyBT, power on your bluetooth GPS and run roqyBT. You will need to purchase a license to use it.

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You will be asked to select your GPS device from a list of detected devices. Put your GPS receiver under a clear sky and you should be able to lock on to the satellites in no time. Once you see the screen above you can press the home button and run your GPS software. RoqyBT will continue to run in the background so remember to click on “Disconnect” once you’re done using it.

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I use Motion X GPS HD for my navigation needs. The trace above shows a typical trip to the shops and the petrol station.

The iPad is a bit too big to be mounted on the windscreen. But it does give you a large screen for route planning or if you’re helping out with the navigation on the passenger seat. RoqyBT works on iPhone and iPod Touch too.

Fun with UV

I went to a garage sale recently and picked up some items for very low prices. One of them was a handheld UV light, also known as a blacklight. It was RM10 only and battery operated so there wasn’t much reason not to get it. And this thing is certainly worth more than RM10 of fun!

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Comes with a torch too. Takes 4AA batteries.

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The blacklight gives a very nice purplish glow in the dark. It doesn’t look very bright because it’s emitting light at a wavelength that’s very near to our visual threshold. That’s the reason why it’s called a blacklight.

The interesting thing about a blacklight is that it reveals things that we cannot normally see using a normal light source. As such, hidden markings can be made using special ink which can only be viewed with a blacklight. The most obvious and common example is our paper money.

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Hidden marks on a RM50 note.

With the blacklight on I went around the room looking for things that glow. White pieces of paper glow brightly because of their fluorescent coating. And here are some interesting things that I found out.

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My KLIA pass has got a security marking that is only visible under the blacklight. It’s marked directly across the photo, probably to prevent people from changing the photo and impersonating me.

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Credit card and IC. The credit card revealed the word “MC”. And the IC revealed my IC number and also a small photo of me! This is by far the most interesting piece of item that I have viewed under the blacklight.

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I also got some stuff on my hands. Can anyone guess what that is? If you’re thinking of something else, I can assure you that it is not that. You’ve been watching too much CSI.

Still looking for more things that will glow under a blacklight. Suggestions?