Sunday, October 14, 2007

USB trouble

My airplane....

... so far. After a couple of strange problems with my new USB hub, I took the old hub I used for my Mac and now all the stuff seems to work as intended. The new hub us now working under my desk and connects Mac, printer and scanner... here it works fine.

The problem was that some devices connected to the hub suddently stopped working. Plugging them out and in again cured the problem but.... other devices disappered instead. A very strange behaviour. Maybe it has to do with the USB device numbering, I don't know how the PC assigns the addresses to the USB devices... maybe it's something different.

However, there are no problems with the Keyspan 4 port hub so far.

Friday, October 12, 2007

Cheap interface

10 buttons for 19 Swiss Franks...

Do you need some buttons or switches hooked to your PC? Simply buy this little USB game controller for 19 Franks (about $15 ). It has 10 buttons, a hat switch and two miniature joysticks... and two vibration motors.
The second picture shows the PCB inside with everything removed except the connecting wires for the buttons and of course the microprocessor on the other side.

All switches have one ground connection and one signal connection, so it will be easy to attach all kind of flightsim switches. :-)

Metal worker

Cut, drilled, sanded....

The pilots instrument panel is finished - at least the metal work. Now the instruments have to be seated into the holes. Some of them will need some additional cutouts but more or less this is it.
It will be painted in black instead of the original army green because it looks better.

Wednesday, October 10, 2007

It feels good...

Today I connected the Connie throttles to the USB analog input controller and after some playing with the settings and adjustments.... it really works.
It's a great feeling to push the throttles forward and to hear the roar of the engines from the speakers. The adjustment is a bit tricky because there are two locations where it must be done. First you do it in the settings of the MS-FlightSim, then again in the settings of FSUIPC. And don't forget to assign the axes to the correct joystick! If there are only two joystick devices (at the moment) it's easy, but if there are three and more devices, you have to concentrate on what you do :-)

I'm happy that it works because the TRC-Simkits analog input is designed for 10kOhm potis and I'm using 50k because I could not find the right ones. To correct the resistance I connected two 20k resistors in parallel to the potis, this gives a total resistance of about 15kOhm and that's fine.
The only disadvantage of this trick is that the travel of the throttles is not linear anymore. The response is a bit flat around the center position but that is no problem.

Sunday, October 07, 2007

Checking altimeters

I am playing a bit with the instruments... again. A few years ago I bought this vacuum chamber and a pump to seal some electronic parts, now there is a new use for it.
It seems the altimeters are still working good, despite my unqualified 'servicing'. Until 20'000 feet they go perfectly synchronous, above 25'000 they have a little difference of 300 ft. But I don't know to what altitude they are calibrated, so I assume that's more or less ok. They won't be used in an aircraft anyway.

By the way... did you know that on 20'000 ft there is only half the pressure than on the ground? It's a vacuum of -0.5 Bar (0.5 kgf per cm2... or 5N per cm2... or 500 hpa.... or 14.76 inches of Hg)
And you have a 80% vacuum at 40'000ft.

Friday, October 05, 2007

Amazing stuff

I don't know why I didn't start earlier to play with the instruments I got. Each one works in a completely different way and all of them are fascinating precision devices.
Yesterday I repaired the gyro heading indicator. The rotor of the gyro was stuck because of corrosion. The whole cockpit must have been standing in the rain or something. Everything shows more or less signs of water damage.
The heading indicator ist an amazing toy :-)... It makes a lot of noise since I'm not able to balance the rotor properly, but it works. It runs on 28 Volts DC so it's easy to hook on my lab power supply.

The most amazing instrument until now is the vertical speed meter. Not so much because of how it works but because it is installed inside an vacuum insulated glass jar (picture). I presume this has the function to prevent that thermal changes can alter the reading.
I already know what to do with this glass thing.... it will be a PERFECT tea cup! I already tested it with hot water from the tap. Outside it stays cool like it was empty. I just have to attach some kind of flat bottom to it.