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Arthur P.

Hacking the I2C interface of Spektrum DX and AR ?

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-AT-LabMaster: Great to hear your continued progress with these receivers :D:D . I had heard that someone else had it working I just couldn’t find who it was or how. For the moment, this simple converter works as well with no additional receiver modifications.

Richard

Edited by brashley

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Hi Walter,

So you were the first ! And one good and one excellent solution. Would be really great if you could provide more details on your current solution for the DX7, e.g. diagram and firmware / source code.

In principle with your solution I could image that you could even modify the DX7 so that you can put multiple switches onto one channel and then use additional outputs on your "receiver" to split them out again. That would e.g. allow activation of different flight mode, airpressure sensor, compass, different GPS modes, return to home, over a single channel with several switching resulting in different binary numeric values.

Re the WL1000 FS solution, is it only the antenna which needs modification, or is this receiver also restricted to a single module with no ability to add a satelite receiver?

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Great Work Brashley! Congrats To AJ as well... (you and Arthur are my personal heros!)

Ive Been following this thread closely (lurker!) because I am designing my MK to fly near Power Transmission Lines for AP inspection.

I have 2 questions:

1. will a 2.4 GHz radio work better than an FM set as far as rejecting EMI

2. Can you post a parts list & etching diagram?

thanks again

Jeff Delvecchio

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Hi Walter,

So you were the first ! And one good and one excellent solution. Would be really great if you could provide more details on your current solution for the DX7, e.g. diagram and firmware / source code.

In principle with your solution I could image that you could even modify the DX7 so that you can put multiple switches onto one channel and then use additional outputs on your "receiver" to split them out again. That would e.g. allow activation of different flight mode, airpressure sensor, compass, different GPS modes, return to home, over a single channel with several switching resulting in different binary numeric values.

That is not so easy, as on the transmitter side the SPI communication between the Microcontroller and the Cypress RF chip seems to be quite complicate, the microcontroller does all the bitstuffing, FEC things and RF Chip registerhandling . To insert more datas it would be nessecary to understand all this in detail. (better get the firmware ripped out of the transmitters microcontroller)

So the things feed into the transmitter RF chip is not that what comes out on the serial communication from the receiver boards.

Re the WL1000 FS solution, is it only the antenna which needs modification, or is this receiver also restricted to a single module with no ability to add a satelite receiver?

there is no possibility to add additional receiver modules to the WL1000, so the only thing that could be done is to tweak the antenna as good as possible, this is not a easy task and seems to be more magic than sience on 2.4Ghz :-) but after a lot of tries i had quite good success, but this is still ne finial solution.

regards,

Walter

Edited by LabMaster

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......

1. will a 2.4 GHz radio work better than an FM set as far as rejecting EMI

2. Can you post a parts list & etching diagram?

thanks again

Jeff Delvecchio

Jeff, I don’t know the answer to 1. above. Needs a smarter person than me.

for 2) I will try to make a Mouser BOM (if I can figure out how) and post the link. For the layout I will have to figure out how to get a 1-to-1 PDF or something.

Actually you need to thanks Mr.Cam for all his help to actually get it to work correctly and Arthur for spearheading this and coming up with the initial idea.

Richard

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PWM-to-PPM V2 parts List: I can create a project at Mouser.com but I cant share it. You should be able to copy and paste the Part Number and Qty into the Mouser BOM import and create your own project or order....

Mouser Part Number--------Quantity---------Desc.----------------------------------------------Ref. Des.

873-AAT3220IQY-33T1-------------1---------------150mA NanoPower VR-------------VR1

583-MM4148-W-----------------------9---------------Signal diode---------------------D1-D9

81-GRM40X105K10L----------------2---------------0805 1uF 10volts----------------C3,C4

81-GRM40X223K50D---------------2----------------0805 0.022uF 50volts------------C1,C2

71-CRCW0805-10K-E3-------------6----------------0805 1/8watt 10Kohms 1%------R1-R6

595-CD74HC221M96----------------1----------------Hi-Spd CMOS Dual----------------IC1

512-MMBT2222A---------------------1----------------Small Signal Transistors NPN------ Q1

Richard

Edited by brashley

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Here is a picture of Version 1 buttoned up and ready to go. I am only going to use this one for testing though.

post-3782-1200167108_thumb.jpg

Hey Brashley,

Are you willing to sell any pre-built ones? Without the receiver of course... :P

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Hi everyone... my quadrocopter is finaly ready. so yesterday i try to test it with ar7000 and it dont works... my board is the an old version i think the november one...

them i see that has a lot of changes and grats results...

my question is does my board version works. i dont have a scope to test it.

one mistake that i see is that i was wiring the ar7000 wrong. the last chanel is ruder.

another thing can you post the schematics here to me?

Another thing... i dont know if the quadrocopter will work with the ppm inverted. does anyone try it?

my is the one of www.uavp.de

Congratulations for your great results.

:D

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Hi osvaldoljunior, the schematic is in this thread at http://www.rc-cam.com/forum/index.php?show...ost&p=18495 . The MK works with this design, dont know about the UAVP but I dont think it should matter. Most microcontrolers are probably "reading" the PPM timing based off of a rising or falling edge of the PPM signal and if this is true it will work both ways. That then means that there really is no "inverted".

Richard

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thanks for the answer. i wiil try to make an discret version of it because is dificult to find all the SMD components here.

whem i finish i will report to you.

thanks :D

one question can i use tl431 in in place of the aat3220?

Edited by osvaldoljunior

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I am not an expert on these matters but it looks like you could use it if you had to but you would need to change that section of the circuit so that you can put in the appropriate resistors to get the 3.1 V from your adjustable shunt regulator. The part I used is a fixed regulator so it did not need any additional external adjustments. Page 25 of the part spec http://focus.ti.com/lit/ds/symlink/tl431a.pdf has a simple shunt regulator application example that should get you started.

Richard

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Sounds like you could... but I am not an expert and I have not looked at the UAVP board. This part of the converter circuit does not use much power at all so as long as you are not already taxing your tl431 you might be ok. Make sure you are using the lower voltage 74HC221 and not the 74HCT221 part. If your UAVP wants the 5V PPM you will still need the 5V. 1) to feed the AR7000 and 2) for the transisotr output section of the converter circuit so you can upconvert the 3V HC221 output to 5V.

Richard

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Hi.. i´ve made my version 2 conversor... but when i test it i found the folowing results....

In the scope i foud only 7 peaks in ppm/out... i test all the chanel of the AR7000 and i found that i cant see the ruder chanel on the ppm out...... another thing... the signal voltage of peak is 5v but the low voltage is 2 volts.... whi i found this result?

do you found something like this... this is the first valid result that i found!

iam using 4150 diods in stead of the 4148 can be this.. i dont think so... and i use pin 4 and 12 to invert the signal

I realy dont know wat more to do..

more tham 6 mouths mounting it and i dont see it fly yet!!!!! :(

:og i`ve found the problem i put a resistor in place of the d8 on pin 12 i cant belive in this.....

This is wath hapens wen you are so hury to make the things works.... and dont have time to make it calm....

Ok i will replace it and tomorow it will work..... :o:D

lets se iof i found the lost ruder!!!

Edited by osvaldoljunior

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Hi..

My conversor finaly works... but i´ve found a pronblem..

the quadrocopter dont allow me to set the chanels order like mk alow.. i need a traditional chanel order like Thr/Roll/Nick/Yaw or Roll/Nick/Thr/Yaw...

has any way to setup it on DX7 or correct the sequence

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My conversor finaly works...

Glad to here you got it working, I was going to say, if the RUDD is not part of the PPM out then something is wrong with the second vibrator but it looks like you figured it out.

Bad luck with the chanel sequence, I dont think you can change it on the DX7 (through standard methods). Perhaps the solution for you is to get the UAVP code and find the channel asignment and manually change it. Just do the remapping on the UAVP side of things. It appears you are having the same luck as me, one step forward and two steps back. You end up getting deeper and deeper into things you never planned on..... :o

Richard

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Yes i got depper and depper... i was planing to try to develop the software of UAVP.... but not NOW....

i talk with wolfer and he sad to me that this wont be soo simple to change on software....

i thing i gona buy a new radio for now!

:angry: -#@$#@%#W$WA@%@#$@FT%%@WEFWER@##@@!--- :angry:

Ok i feel better now... :(

i wiil got you updadtes

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That is too bad that the Quadrocopter firmware does not allow you to customize the servo order.

I created a PCB for the V3 DX7 PPM interface. This version is loosely based on the posted design. The most interesting change is that it includes a microcontroller that will be used to detect the DX7 failsafe (via the throttle channel). Unfortunately, I haven't had any spare time to complete it, so it is still on the honey-do list.

Below is a top side photo of the V3 PPM interface PCB (more components are on the other side).

post-2-1203537939_thumb.jpg

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That is too bad that the Quadrocopter firmware does not allow you to customize the servo order.

I created a PCB for the DX7 PPM interface. This version is loosely based on the posted design. The most interesting change is that it includes a microcontroller that will be used to detect the DX7 failsafe (via the throttle channel). Unfortunately, I haven't had any spare time to complete it, so it is still on the honey-do list.

Below is a top side photo (more components are on the other side).

Very nice :) , do you need any help??? (looks like you used diod arrays, much better)

Richard

Edited by brashley

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Sure, I can always use some extra help. Be sure to bring along your soldering station, C-compiler, and favorite caffeine laced beverages. :)

The diode arrays are nice, but have very small 35 mil pitched pins. So, the magnifying lens gets used to place and solder them. The photo does not readily show how small these parts are!

With luck I will get back on this is a week or two (have been telling myself that for awhile now). The only Spektrum system that I have to test it is a DX6, so I hope that it is similar enough to debug the latest design.

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Yea, I know what you mean with those diode arrays. Pick some up on my last order incase I was motivated to redo the layout and compress it. I was shocked at the size when I got them. My first layout was actually kind of inefficient space wise. I just finished a layout for your PanCam chip with pan, tilt, bypass, and center (like your last design) and have it squeezed down to about 15/16" X 7/16". Will try to make the PCB by this weekend. If you want I will start a new thread and post the results.

If your current design is just double sided I could probably try and make one and try it with the DX7/AR7000. I will have to wire up a little SOIC socket so I can program those small PICs as well (need that for the Pan/Cam project also)

Richard

Edited by brashley

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If your current design is just double sided I could probably try and make one and try it with the DX7/AR7000.

After I complete it we can try to work something out (for example, I have a spare un-stuffed PCB that you could use). But until I validate it, sharing the new design is not something that I would want to do.

I will have to wire up a little SOIC socket so I can program those small PICs as well

The microcontroller I am using is a tiny SOT package. Fortunately it is also available in a giant sized SOIC. :)

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It is a good news have one microcontroled conversor.... but can this conversor reorder the crazi sequence of AR7000... i need to know if i will try to change uavp software... make a microcontroler based conversor or buy a new radio system.....

Considerating that i need to learn all about pic and programing a pic i think i gona buy a new radio to get it work until i learn about it

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