27 février 2009

Transmitter case alu prototype

The transmitter case is almost finished. This is a prototype made with alumininium and epoxy plate (printed ciruit plate). If someone is interested, I can explain in another post how I built it. From the initial drawing, there have been some changes, such as dimensions.
But it is close to what was designed with Styro , except the round corners.

Knob unders the sticks are use both as trims, and as input for the lcd interface. It is planned also to add encoding wheel.
Stick are those of a Futaba FC18 with their trims removed. Mechanical trims under the sticks have finally little use, so they have been replaced by kind of "auto-trim" or preferably what I call "obo" trim.

Sides where hands hold the radio, are rounded. It is more comfortable to hold the radio, and to move the hands near the stick.

This case is mainly for pilots who use inches on (pouces dessus).
The display is a classical graphical lcd 128x64 and it sits between the stick as there is not enough space above, due to the compacity of the case.

Overall weight of the case is reasonable and should be fine when electronic and batteries will be in.


To make a size comparison with the Futaba T12Z, the case is larger but less long, and thiner than the 12Z. It feels also very comfortable in hands compared to the 12Z.

20 février 2009

Transmitter box styro prototypes

After drawings, it is time to make some box in styro, to better feel the shape and how it will fit in hands. I made several trials. It's not easy to find the perfect balance betweeb size, shape, sexy look, good ergonomy, light weight, etc... The prototype will not be perfect for sure, but it will benefit to check the dimensions, size, and ergonomy. Let's hope it will work like that, it would be nice to keep the box small if possible.




09 février 2009

Differential mix variable rate

Another video to show how Aileron differential is reduced when using butterfly mix such as it can be in a competition glider. Very useful to keep turning while airbrakes are fully out.
video

08 février 2009

Atmega328


Another interesting chip as a possible improvement of the Atmega168. Same pins, but more SRAM (2k) and more Flash(32k). It should fit in the Arduino easily.
Nice evolution to the atmega168, but has some drawbacks:
- the bootloader from Arduino do not work from scratch,
- the tools avrdude, gcc-avr do not know the 328.
[edit] correction:
- the last version of Arduino (0013) supported the 328: It provides avr-dude with the right conf file, and the bootloader source file and Makefile have been updated for the 328,
- I tried to define m328p as a target for avr-gcc, and it works also.

So no more reasons not to replace your 168 on the Arduino by a 328!

02 février 2009

Unigen module

Today I received a new toy :)
Could be a good replacement for the XBee module, less expensive more flexible, approximately the same size than the Maxstream Xbee pro.