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Topic: Cheap UHF spectrum analyzer (and RC tx rx) using RFM22 module (Read 49 times) previous topic - next topic

msev

#5
Mar 15, 2012, 03:59 pm Last Edit: Mar 15, 2012, 04:32 pm by msev Reason: 1
Thanks for the schematics! I would be interested :) in a few (3 or 4), I don't care about size, for me bigger is better since its easier to solder slightly bigger stuff..Very nice!

Would you also share the code? Is your code also frequency hopping? Do you have failsafe implemented? Do you have rssi implemented (would it be possible to have an audible alarm, if I connected a buzzer to the board), can rssi be taken from the board (on the plane or heli) to an osd? Is it possible to configure the power output of the module - for example to use a booster.

Are you familiar with multiwii (http://code.google.com/p/multiwii/ , http://www.multiwii.com/ )? Probably it would be possible to incorporate multiwii in your design, because the relevant pins (SDA and SCL) for interfacing with sensors are free right?
I would like to have my plane stabilized and autolevel,...Since your board is 5V unlike Melihs, I can use a original wii-motion+ as a gyro,...and as a accellerometer I will use a adxl345 which has already an LLC and voltage reg. on board.

Instead of using a SMA connector like on your photo, could I just solder the coax directly to the pins? (central conductor+shielding)

Are those two leds on the board useful for diagnostic if the boards are working, for example uploading blink sketch?

How far away did you go with your heli :D?

zitron

#6
Mar 15, 2012, 11:57 pm Last Edit: Mar 15, 2012, 11:59 pm by zitron Reason: 1

Would you also share the code? Is your code also frequency hopping? Do you have failsafe implemented? Do you have rssi implemented (would it be possible to have an audible alarm, if I connected a buzzer to the board), can rssi be taken from the board (on the plane or heli) to an osd? Is it possible to configure the power output of the module - for example to use a booster.


Ok lots of questions...

I yeah I will share the code, there are some problems with it. The arduino servo library creates weird glitches, so I had to use software servo. I would also like to test it some more before I give to other ppl. I don't have FH right now, but the RF22 library supports it, so will not be too difficult if you want to add it yourself. RSSI yes, you will have to use analogWrite and low pass filter it if you want to output a voltage though. I actually have a header to add a switch to change the power from 1db to 20db for range testing.


Are you familiar with multiwii (http://code.google.com/p/multiwii/ , http://www.multiwii.com/ )? Probably it would be possible to incorporate multiwii in your design, because the relevant pins (SDA and SCL) for interfacing with sensors are free right?
I would like to have my plane stabilized and autolevel,...Since your board is 5V unlike Melihs, I can use a original wii-motion+ as a gyro,...and as a accellerometer I will use a adxl345 which has already an LLC and voltage reg. on board.

Instead of using a SMA connector like on your photo, could I just solder the coax directly to the pins? (central conductor+shielding)

Are those two leds on the board useful for diagnostic if the boards are working, for example uploading blink sketch?


Ok a bit of bad news. I planned to use the arduIMU for stabilization, so I did not really want to use I2C. So although you can use SDA and SCL, they are also used for the LEDs! So if you want to use I2C, you can't use the on-board LEDs.

Yeah you can definitely just solder coax directly to the board, that's what I did on my prototype.


How far away did you go with your heli :D?


Not very far, maybe 25m. It's a small HK450, I can only see it that far...

msev

Hi.. What about failsafe? Do you have it already implemented, could it be implemented that one would preconfigure the arduino sketch to a certain level of rssi, and it would go in to failsafe then...

Did you make your own antennas for your LRS? Are you planning to make a LOS test? People get about 4km with openlrs on omnidirectional antennas..


zitron

No I do not have failsafe yet, I've only just started the project! I have the bare minimum: a tx which reads PPM and a rx that drives servos (and some basic mixing). If you want failsafe you will have to do it yourself. Are you able to write code for arduino?

I did make my own antennas, see the pictures in the first post. I want to do a LOS test but it will be difficult where I live.

I have another person ask me for some boards, I only have 4 boards left, if he still want them, you can each have 2. PM me where you live I'll look up how much it costs to post from the UK. Or I can give your the gerber files so you can have boards made yourself. Make sure you can source all the components, I have attached a bill of materials.

zitron

#9
Mar 17, 2012, 03:26 am Last Edit: Mar 17, 2012, 03:30 am by zitron Reason: 1
Here's a scanned picture of the board, so you can see the details. Note that there is a mistake, R1 should connect to the atmega reset pin (the square pin), not to C5. It still works, but if you have problems with serial auto-reset, you should cut the trace and connect R1 to reset directly.

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