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46  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: April 12, 2012, 04:40:29 pm
The joystick will be a old but cool "Top Gun" , and a pair of old T2m rudder pedals, all for FPV obviously.

Wow that is pretty cool, and yes LM7805 will work fine, that's what I use. The board draws very little power.


Also I thought I should update the schematics and bill of materials, there are some slight changes. See attached.
47  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: April 12, 2012, 11:29:45 am
Can you upload your modifyed library or explain here what to change?  Did you solved the glitches issue with this mod?

Well I fixed the glitch problem awhile ago by using software servos, now hardware servos are also working, which is more processor efficient.

I will try to release a simple "reference" code sometime next week, it will include all the libraries, and will be a simple PPM->Tx->UHF->Rx->Servos thing.

Edit: Important notice, please make sure that you can find a 5V source on your radio, this board does not have a voltage regulator for the arduino, so you can not power it direct from your TX battery. 
48  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: April 12, 2012, 11:22:39 am
I'd be interested in buying a booster pcb from you (same layout as Melih for the same chip), maybe if you could design it in a way that the resistors, caps, diodes,  etc would be of a bigger size, for easier diy work...Do you manufacture these pcbs by yourself?

Yeah except I really don't know much about RF design... If I tried to make one of those high power amps it would probably catch fire!
49  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: April 11, 2012, 05:42:12 pm
Here are some pictures of the new Rev 2 board. It's 50x43mm compared to 50x50 Rev 1.

If you are building one I suggest soldering the SMD components first, and use a bigger cap in C7 (I said 100uF in BOM, probably should be 470uF) especially if you use a lot of servos.
50  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: April 11, 2012, 03:40:50 pm
I can solder SMD and get all the components needed; I have lots of open source arduino projects done but... I don't write arduino code... if you do not mind sending me the actual code, as well as any updates, I think I'll have no problems. If you do not mind that your project is shared, I think it might bring some progress in the project through some friends. But as I said before ... I do not write code...
Zitron What do you think? It is worth I join the project? 

You/anyone can use my design files and code for whatever purpose. Just make sure you know what you are getting into, it's not a fully featured product, and will likely to have many problems.

Zitron sorry for the late response.. You can send/sell the pcbs that you reserved for me to other guys...
I'll probably make my own diy single layer boards and use an arduino nano..I'll make the connections per flytrons schematic so that I won't need to tinker too much with the code..I'll make the nano removable so that I could remove it from the board when uploading new sketches (since 5V would kill the rfm22b)..

I would take yours if there would be a possibility to easily port openlrs code...but its a bit too complicated for me..
Hope you continue with your nice project and post code...Hope then when you write your code for lrs you'll still have some pcbs to sell smiley-grin.

I think that is probably the best thing for you to do. Trying to port someone else's code will be very time consuming, especially if you have limited experience! Also bear in mind that by the time you bought your nano, all the components and boards I think you might as well buy direct from Flytron! It would be really nice if they released a DIY OLRS kit.
51  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: April 11, 2012, 11:52:22 am
Oh also if you want to know where to get the RF22 module, have a look at the HopeRF resellers, find one near you: http://www.hoperf.com/agent.htm

I get mine from Germany.
52  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: April 11, 2012, 11:44:40 am
OK guys sorry I can't keep giving away boards for free. From now on I will charge a small fee (£2 per board) just to cover my costs.

Before you decide to start this project, make sure you can write code for arduino, ideally have some knowledge about SPI communincations, can solder SMD packages, and can find all the components that you need, listed in the BOM pdf attachted in a previous post. I can help, but I don't have time to answer all the questions.
53  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: April 11, 2012, 11:37:31 am
Hi Zitron,

Discover the secret - where do you manufacture the PCBs?

I use iteadstudio.


edit: BTW did you manage to get it working?
54  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: April 10, 2012, 05:49:34 pm
Yeah I can send you the 3 rev 1 boards msev wanted. I can send him the new boards if he still wants them.


BTW I don't know if anyone would be interested in this, but I have found that the RF22 library is not compatible with timer based hardware servos. Very weird and hard to debug. It is because the interrupt driven read function takes too long, messing up servo PWM timings. I had to modify the library quite a bit, but now I have hardware servos! If anyone else have problems with the servo library I'll let you know what to change.
55  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: March 21, 2012, 05:27:14 pm
Devonian are you willing to modify the interesting features of openlrs firmware (failsafe, rssi etc.) to work on this nice hardware?

Edit: Zitron hope you received my pm with my address. Zitron hope you retain the same connections on your board so more code fluent friends on this forum can help me out with the code smiley-grin

I will reserve 3 for you and send 3 to Mauzer. So now I don't have any more to give away.

I have attached my Tx code, an Rx test code (no servo) and the code used on my HK450 heli, which is a little bit complex because it has CCPM and PID governor. You need to install the arduino RF22 library, and software servo library (I'm having some glitching problems with the default hardware servo library). Please understand that this is just my personal project, not yet a proper ready to use general purpose tx/rx, I have only implemented the things I wanted.

Right now the software only supports transmission on a single frequency (I set it at 459.5, but you can change it to whatever you want), 8 channels at ~50Hz. The Tx takes PPM.
56  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: March 21, 2012, 05:10:52 pm
I see you are in the UK, have you seen the FPVUK forum post(s) regarding 459MHz use?
It would be good to see you over there.

http://www.fpvuk.org/forum/index.php?topic=2551.new;topicseen#new

The ability to use 459MHz was partly why I started the project! I have been reading the fpvuk and openlrs forums for a while, but I don't really want to go in and be seen as competing with OpenLRS. This is just a personal project. Although it would be nice to have some local RC people help with some testing. I don't really have many friends near me that enjoys going out to do range tests!!

What are your plans for the smaller PCB?

I'd be very interested in a couple of smaller (Futaba module compatible) boards - I'm willing to assist with costs.

They are only slightly smaller. Rev1 was 50x50mm, Rev2 will be 50x43mm. Right now they don't quite fit inside my 9x radio, the new ones should just fit. They are not designed to fit into Futaba modules, and because they run at 5v you will need to modify your radio slightly to get a 5V wire out. I attached some pictures to show how ghetto my mounting method is!

I would like to keep the large DIP 28 atmega328, because it's easier to get, solder, program bootloader and because I have a lot of them! Making boards is really cheap, I don't really need any financial support for that. What I plan to do is release the gerber files, so that if anyone want some boards all they have to do is to send the files to a PCB fab. It would be really nice to have more people help with the software though.
57  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: March 20, 2012, 08:15:38 pm
Good news, I decided to make a new version of the board (just smaller and fix the reset resistor). So if you guys still want the current boards you can all of them (3 each).
58  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: March 16, 2012, 09:26:35 pm
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.
59  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: March 16, 2012, 08:10:08 pm
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.
60  Community / Exhibition / Gallery / Re: Cheap UHF spectrum analyzer using RFM22 module on: March 15, 2012, 05:57:14 pm
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 smiley-grin?

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