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RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
have you tried changing Xtals? Had it any crash? Or have you dropped the transmitter? I had the same problem, but it was because i burned it, and solved it replacing the TA31136... not suitable for someone with not many electronic skills.
Posted on: 4/5/2008 5:06 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=7337699
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
No, i dont think thats it. As far as i have seen, this Zen Hua is a protocol for transmitting data to PC when using for simulating, for example. I was referring to the widht of the pulses walkera uses, they are different from standard PPM, although not very different... thats why some receivers work, and some others dont. On the other side, this 5 byte protocol is a form of PCM. If a transmitter is transmitting PCM, it will not work with a PPM receiver, and vice-versa. I have not found a single person having a DF#4 and a PCM transmitter... if you know someone, please, invite him here, we can all learn from it.
Posted on: 12/9/2007 1:16 AM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6732869
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
sorry, RDY12. We'll try to have a less technical chit-chat. Yes, the Tx is a normal Tx, at least, the walkera #4 stock has. It has, however, some particularities, for example, it transmits 9 channels, with 4 active and the other 5 stuck in minimum. Also, the PPM in not entirely standard, its a bit "special", some receivers may not woak with it. But, the 4 active channels dont have any mixing, any processing, or anything at all. Correspond exactly with the movement of the stick. All the magic is done in the receiver: demodulation, mixing, gyro, ESC (wich, incidentally, is the way i think everything should be, so you have just one ontroller for everything...)... The thing is, for example for a walkera #4, its hard to find a standard 9 channel PPM transmitter... so you cant use [i]any[/i] transmitter with the receiver.
Posted on: 12/8/2007 10:41 AM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6729784
RE: Controller for Coaxial Helis.
OK, that question can have many answers. Ill try to resolve it to one: You need 8 PPM channels... to keep programming simple, i'd use interrupt, no polling. So, we need interruptible pin ports. Usually, this ones are located on PORTB 8 pins. + You need 8 analog inputs... that can be a bit difficult, but suppose we have 8 inputs, and they are not shared with above or below pins 8 pins + I2C (2 pins) + UART(2pins) + Vcc(2pins) + Xtal(2pins) And enough core and speed to crunch all that together in less than 20 mS with a nice algorithm... ok, if you want to over-react a bit, id say a dsPIC would be fine. But, a PIC18 would work well. PIC18F452 is one of the most commons (at least, here in Argentina), my thesis partner and I are programming them for our thesis. With 452 you can get 8 interruptible inputs, UART, I2C, and 8 ADC10, and some spare pins... the thing is... its a DIP40... a bit big. If you can get (and solder, and make a PCB for) the SMD version, then its smaller, more RC usable. The compiler we use, PIC C, its a bit sluggish, and the code its not very clean, but, it works, and you can compile for PIC12F, 16F and 18F. With an 11,0592 MHz Xtal, it crunches numbers with average speed. You may want to try it, at least, to begin experimenting with. :) The 12F675 is very small, thats the main advantage it has. We can fit even a small PID with integer math...
Posted on: 12/5/2007 11:40 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6719934
RE: antena wire
Hello rody! if you dont know some electronics, its gonna be harder but ill try to help you. The antennae goes to an inductor, and a capacitor, and there it goes to the TA31136. You should find then this inductor and solder it. If it gets hard, ill try to post a pic later.
Posted on: 12/4/2007 4:58 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6713379
Controller for Coaxial Helis.
Hello! im starting this thread since in the "other one" we were becoming a little astray. The idea behind this thread is to build a controller for coaxial helis, since some of them (most of them) dont have too much flexibility. In most of them you cant add your own ESC and Brushless, for example. Involved in this loonatic project, we have [link=http://www.rcuniverse.com/community/profile.cfm?section=profile&forum=1&memid=342930]Hughesdb[/link], [link=http://www.rcuniverse.com/community/profile.cfm?section=profile&forum=1&memid=269378]UShobbysuply[/link] , [link=http://www.rcuniverse.com/community/profile.cfm?section=profile&forum=1&memid=253734]Jtspin[/link], [link=http://www.rcuniverse.com/community/profile.cfm?section=profile&forum=1&memid=213922]RDY12[/link], [link=http://www.rcuniverse.com/community/profile.cfm?section=profile&forum=1&memid=206333]GTX Slotcar[/link] and me. We like programming, electronics and RC....and like to put them toghether. We have some ambitious goals, involving perhaps UAVs and Autopilots, but we'd like to begin simpler. Ok, here is the first scratch. A very simple schematics, to start developing code. The main idea is simple. From a standard receiver we feed THROTTLE and RUDDER + GYRO into the mixer, and get 2 outputs, M1 and M2 wich are simple, standard 1-2mS PPM signals, to attach 2 ESC that command both upper and lower rotors, in a Coaxial Heli setup. Hughes can give more details to anyone interested. We have decided to use a PIC, because its more common and tools are easier to find. Nevertheless, we can start another (or the same) project with Motorola HC08, ATMEL ATMEGA, or any other microcontroller. Here are some basic points, that hughes and I have agreed with: - It must have security features (for example, if invalid signals present -> go failsafe or do some specific task, drive ESC gradually to zero, or sth) - Must have variable Mixing percent. - It can respond immediately to a valid signal after noise or invalid signal, or it can wait until throttle goes to zero...both look good. If anyone comes by and like to join, is invited! Also, comment, criticise, collaborate, help, push, shoulder, anything, as much as you like! We are trying to do something useful, for us and for anyone who wants to build a savage untamed coaxial with a big LiPo and 2 power Brushless...! e.
Posted on: 12/3/2007 4:44 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6709036
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
Hello GTX! Thats a possibility.... however, we've just started! We are doing this for fun, but, an extra income is never overlooked! ;) Ok, less joking, if you see improvements that can be made, things that can be changed or whatever, please feel free to point out or make some critic about it! We are at the design stage, so everythings changeable and we throw nothing! And please, do come often and collaborate! e.
Posted on: 12/3/2007 3:25 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6708705
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
no, rdy12! dont leave! the more the merrier! we´re about to start a project, we're begginning with a custom mixer pic12f-based for a coaxial heli hughes is working with. The thing is, the components hughes has are not well suited for the job, so we are trying to do our own and tweak them to see if they are better. If youd like to participate, like to program, love to crash helis, or anything alike, please do participate! BTW, i apologyse, hughes and JT, ive disappeared a while.... tomorrow ill have my last-before-thesis exam, ive been preparing that... but after tuesday all come back with news. cheers!
Posted on: 12/3/2007 8:29 AM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6707372
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
[quote]one inputs the rudder and the gyro adds the correction needed to rudder signal. [/quote] You are righ... in fact, the diagram changes a bit, the first wouldnt have work. ill post the second anytime. [quote]Alternatly, we could use the simple gyro chips as in the 4-in-1 - in a second version i would love to try putting 3 of them! However, this would need an ADC.[/quote] Thats the second idea, the 12F675 has internal 10bit ADC. [quote]I am not sure u need to feed back the aile and elev in the e-sky receiver, unless u want to do clever things with them. [/quote] its easier, since in the board are the sockets with +5volt and ground for the servos. [quote]Concerning PCM, I saw the coding somewheer.[/quote] The thing is, Futaba has its own coding, JR has its own, and so... ive manager to get a document with the Walkera 0701 coding...but only that. [quote]Third schema looks good.. even I can build that! The 'flux diagrams' are called 'flow diagrams'. [/quote] Thats the idea!! it must be easy, so we can build it and roast it and dont have a problem. And thanx! it was flow diagrams.
Posted on: 11/30/2007 11:39 AM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6694947
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
ok, the new thread sound great. we should open it now, with the beggining of this project. Here i post three pics, with somw general draws of what it might be composed of, or at least, very general schematics to begin programming. Pic1 is the basic project we'd like to do: a simple PPM signal processor, takes in 3 (at least, in the first design) standard PPM signal (1-2mS), processess them with a custom proprietary ( ;) ) equation and outputs 2 standard PPM signal 1-2mS for feeding 2 ESC brushless or whatever. We need the 3 inputs to be interruptible (out of simplicity more than anything, and for the sake of precision, also), a 16 bit timer so we can count directly in microseconds and not worry about any carry, flag, char-to-int, etc (4MHz /4= 1MHz -> 1uS each count -> we can count from 0 to 65535 uS, more than enough to count from 0 to 2000uS). We'll defin later some software general lines, thats the basic hardware we'll try to use. The second pic its another idea, we can use the e-sky(walkera) pcb since it has a complete FM receiver, signal conformation and data slicer, and ALSO it has a pure amplificated GYRO signal... we can do a lot of crazy stuff with that, head lock gyro with PID algorithms, change parameters, have non-linear gyro responses... i dont know, anything's worth try. The ouput is, again, 2 ppm standard for ESC brushless. Its a bit simpler, since instead of waiting 3 "independant" signals, we have one composite PPM signal with all the channels and stuff... and, shure enough, if the receiver is a common TA31136, any FM non PCM transmitter is elegible for use with this receiver. Even a PCM, if someone there has the decoding key. The third and last photo is a simple, incomplete schematic of the hard ill have in my protoboard to begin programming and experiments, perhaps you hughes want to have the same set upm so i send you the source code and you compile/download it with no modifications... We'll discuss software later, i have also some incomplete draws of flux-diagrams (is that so in english? Diagrama de flujos? you know, circles, squares, arrows and stuff to indicate operations?)...but i've had a long days, and another long one expects me tomorrow, so i'll sleep a bit. CU guys!
Posted on: 11/29/2007 12:08 AM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6688828
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
Hi, jtspin! join the madmen circle! I wouldnt advise re-programming the receiver... the program works, right? Its better to test it and try to figure out what was the thinking the one who programmed it... Id choose to program another uC and keep the original, so you have one good working to compare with... at least, that my politics. Were trying to program some microcontroller with our custom programs, so we can crash home-made helis, and blame it on the compiler instead of some guy in Hong kong. Hughes has a coax heli, and we have decided to try and program a uC so we can put it in the air... wanna join?
Posted on: 11/27/2007 9:40 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6683329
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
ok, lets go step by step. [quote]PWM is about 5k Hz, going from 30% to 90% duty cycle (approximatly).[/quote] Check this value again. If duty is 30%, the 5khz tone would be audible and the motors would have some lor rev. spinning, even with the Throttle at 0.... [quote]Throttle input goes to the INT(errupt) pin and the rudder to CIN-, the comparator input. I assume a difference between CIN+ and CIN- generates an interrupt?[/quote] Not likely. how you gather Rudder goes in Cin-? Perhaps, the PPM signal goes INTO INT and you get some signal OUT P55(Cin-). Usually, the comparator is not used (at least, thats what ive saw). If you see a lot of noise when you turn the Remote Controller OFF, then thats the input for the composite PPM signal that comes out the FM demodulator/RF stage. And, some signal for a servo goes out the port pin... at least, thats how it happens in the 4-in-1 DF#4 has. Have you seen a composite PPM? (NOT the servo signal)... [link=http://www.mftech.de/ppm_en.htm]Here[/link] youll find some information, some numbers may vary, dont take everything in literally, but on the whole the concept is OK. For example, walkera uses around 1200uS for the middle position, instead of the "standard" 1500uS. [link=http://www.mp.ttu.ee/risto/rc/electronics/radio/signal.htm]Here[/link] is another real good page, very clear and didactic. [quote]ps. looks like we are the only crazy ones in this forum! Maybe we should start a thread just for this subject.. what do u think?[/quote] Maybe its a good idea! Weve gone a bit astray here. Something with a more descriptive title? I dont know, but the idea sounds great. OK, you seem to be going really good with the osciloscope! Its pretty good, ive compared with my "real" one and its pretty accurate... at least, in my pc. Ill try to do some photos of the receiver i have, it uses the same uP, and post where i get wich signal. Thatll help us.
Posted on: 11/26/2007 9:40 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6678463
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
Ok, so hands to work. Perhaps the set up youre using cant perform any better, i mean, that is the best youll get off it. Maybe, with another gyro, a V mixer giving you more freedom with variables, etc., something better could be done... but, well, that is another field. [quote]Here are some rules : 0) Basic rule is :[/quote] not many people would understand why you start with 0, and not with 1... im surprised you havent ended the sentence with a semicolon! ;) :) Ill try to get a small PIC, for example, 12F675 or alike, so theres very little space and weight in the project. See if the hardware you have (programmer, compiler, etc) support this family. To begin with, the ecuations youve stated are excellent and self-explaining. But i dont know if the would work well with different gyros (Normal and Head-lock, for example). However they are good point to start tests. [quote]OK, looks good but i think we need gyro, rudder and throttle. I'm assuming we will work this with a simple simon 4 channel dumb transmitter.[/quote] Yes, i meant Rudder. Ive never learnt the names in english, its like larboard and starboard, or prow and poop...never could tell them apart on a single shot. The rules are OK, ill add some little bits as an extra precaution. For example: [quote]3) In the absence of inputs, some neutral value is assumed, gyro action continues operating [/quote] -> The program "creates" a THROTTLE signal wich goes from the value it had untill it lost signal, gently decreasing to zero, and then both ESC and gyro stop working.... and stuff like that. Ill keep you informed, it might take me a week to get some PICs and maybe 2 more to get some decent working-code. I never replied some things, those probes you showed me are good. They are active probes, it means you need to feed them with a 9 volt batt or something, but they are bound to work. The signal goes in through the LINE IN jack. I tell you again, be careful, try not to roast anything in the motherboard. Ive tried the soft, [link=http://www.audiotester.de/]Audiotester[/link], it seems awesome. Its a bit buggy, but considering its shareware, its great. You can try to get a capture of the signal that comes out of the receiver an goes into the 4 in 1 uP. You might want to start with the signal present in pin 1, thats the NMI of the uP, and most walkera receivers use this as an input for the incoming PPM/PCM signal. OK, ill go for now. Mail me if you need any help.
Posted on: 11/24/2007 2:22 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6666832
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
ok, here is everything glued together. #52 receiver and #4 frame. The servos are e-sky, they must be modified too to work properly, because the center PPM widht pulse walkera uses is about 1250 uS...minimum near 700uS and maximum near 1800uS.
Posted on: 11/21/2007 2:52 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6654897
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
here i post two images, one showing everything before any change and the other with the nasty artwork done. Basically its adding more power, thats all. Ive bypassed the onboard mosfets and added a plug, mosfet and mosfet driver of my own. Ive not tested any of that yet. [quote]rx601 is made for the CCPM helis - i have one on my DF52 - which is 120° swashplate - and the DF#4 is 90°[/quote] yes, ive a DF52 too! in fact, i got this receiver from walkera after purchasing my DF52, i thought it was a good idea to have a #4 controlled by a #52 radio. The rx601 is just a 6 channel PCM receiver, the hard work is done at the controller, and it has on the back some DIPswitchs for configuring operative mode. So, you put CCPM/NORMAL in NORMAL mode, and is just a transmitter. Plug the servos on the AIL and ELEV plugs, and.... well, everytime i go on after that, something gets broken. But it will fly....eventually. What i really like is that you can control exponencial curves on the sticks and can modify gain/type of gyro... [quote]I have some stuff for PICs, including the dsPIC 28 pin[/quote] Ok. So, we can program a PIC, wich accepts THROTTLE, AILERON and GYRO signals and translate them into two signals PPM for MOTOR1 and MOTOR2.... or at least, that would be a starting point. Which model is the V-Mixer and gyro you have? I want specs.... im still convinced something can be done with those.
Posted on: 11/20/2007 10:20 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6652266
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
Yes, the "metal casing" chip is the gyro, youll find hardly any spec or datasheet. Its a piezo gyro, most of them are manufactured by Murata... i cant tell you much further than that. If youre interested, ill try to explain how it works, from what ive gathered after reading several "almost" datasheets and briefs... if you are not, its enough to know that they give a signal, an output voltage proportional to the angular speed on one axis. They are active, it means they need proper feeding, and output 2 signals, a reference Vref and the output itself, Vout, referenced to Vref. The uP is a common, 8 bit, 10bit ADC, 16bit-2 channel PWM, RISC arquitecture microcontroller. Quite much like any PIC... but better ;). And yes, it runs on 4MHz. The diodes are protection and/or freewheeling diodes. Drags my attention both pots, apart from the gain pot.... the Zero pot, and the other, what do they do?... As i can see, there is a recepcion PCB and a processing PCB...thats good, perhaps we can try some home-made controller.
Posted on: 11/20/2007 9:15 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6651926
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
i forgot, [quote]The two little chips in the middle are pobably to drive the mosFETs (one of which is burnt on this photo) and on the left is the gyro chip and a an unknown chip. On the other side of the circuit is the xtal, microcontroller, 2 pots to adjust parameters and the stabilised power supply[/quote] send me 2 photos of the best definition you can get, or send me the numbers on every chip, the "unknown" chip must be an LM324, or some quad amplifier, used as a data slicer, ampli for the gyro, etc.... ok, with the number well discuss more accurate
Posted on: 11/20/2007 5:54 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6651013
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
[quote]if u care, I could send u the 4-in-1 to see if we can get a signal. [/quote] noooo, dont send it! It would be a lot of money, just to send from switzerland over here a small PCB. We can do some otrer things instead. Do you know some electronics? A little bit? You can use your computer and turn it into a cheap oscilloscope. Of course, you have to make you own probes, and you must be very careful or your PC will blow away... ok, not blow away, but theres a pretty good chance you will never hear an MP3 again. Anyway, here, [link=http://www.aubraux.com/dsp/index.php#download]DspSee[/link] youll find the program. It uses your soundcard to acquire signals and present them "like" an osc, its NOT like having a real Oscilloscope, but useful enough for sampling PPM, PCM and RC signals. If youre interested, i can help you with the probes and stuff. [quote]I tried a V-tail mixer to distribute the correction to both motors but did not get satisfactory results[/quote] I dont get why it didnt work well.... i mean, at least in theory it sounds great. Perhaps the mixing percentiles? Or the gyro gain? There are a lot of variables to play with... we could try a programmed mixer, wich microcontrollers are more common where you live? PIC? AVR? I mean... wich would be the easiest for you to program? so i send some C source, and you program and try. [quote]One of my fun versions had 4 gyros - one acting on each motor and one on each servo, so the yaw, pitch and roll were stabilised![/quote] Formidable!!! its so simple i had not think about it before... i have to try that on my heli.... big $$$, but its worth to try. [quote]If I were designing this circuit, I would use standard modules - for the channel / gyro mixing - giving me a PPM output which I would then feed to the circuit which controls the brushed motor.[/quote] Yes, perhaps that wuld be the easier way, but not the cheapest (important), nor the most straightforward. If you have a microcontroller, you can do a lot of stuff "inside", in a discrete, precise, fast way, and the you transform and output the result the way you want (namely, PPM, PWM, led blinking, etc.)... i dont think youll find a PPM wiht the mixing result. [quote]Are u interested? I am a software engineer, although not much experience with on-board stuff, but willing to learn. [/quote] Of course im interested! Im almost an electronic engineer (hope to become a solid engineer on March next year), and also willing to learn so we can do some stuff. Ive just finished hacking a walkera RX601 receiver to work with a walkera #4, i send photos...once ive learnt how, and i think it will be flying soon.
Posted on: 11/20/2007 2:06 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6650076
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
ahh, ok! i get the idea. the thing is, its completely different a dual-main rotor heli compared with a "normal" heli. I dont have any of them, but, from what ive read, there are several important differences, for example: both rotors are used in lifting the heli. so, both must work in conjuntion to provide the lifting force. the gyro signal is used to make one rotor spindle faster than the other, so the resulting "total rotating quantity"(1) compensates some outer force or makes the heli turn. in order to do that and not cause the heli to drop as a stone, both rotors are mixed in such a way that when one goes slower, the other rotates faster, the total rotating quantity changes but the lifting remains "more or less" the same. In a normal heli, however, the gyro never mixes into the main rotor, so I dont think it will work properly, much unstability and stuff. But.... i take note of your project. Its very interesting, i would like to know what ideas you have and what youve done. We could even do some microcontroller programming and try to make the thing work properly. [quote]surely the pwm 2kHz signal would be ok to drive a brushless ESC ?[/quote] im sorry... its not like that. this PWM is a signal that ranges from 0% to 100% duty cicle according on the gyro and stick signal, and cant be fed into an ESC, normaly ESCs only accept standard PPM signal... and they are very very different. (1) sorry for that. im almost an engineer, and i have a very strong phisics formation. however, i have studied everithing in Spanish (my mother language) and i dont know if thats the correct expression in english. also, i apologise for my grammar mistakes... :S :S :)
Posted on: 11/18/2007 9:01 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6642531
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
im sorry, the only signal you can get is a PWM of around 2 khz, wich comes out of one pin and feeds the mosfet strightaway. It doesnt have even a resistance. The mixing, gyro and ESC functions are internal, in the uP. What you can do is take this signal, and put it on a larger MOSFET. But why would you want to feed a brushless ESC?
Posted on: 11/17/2007 4:00 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6637158
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
aha, so perhaps its older and the plain PPM are newer. if anyone has any of this zhen hua TX it would be nice to have an oscillogram posted, maybe we can draw some conclusion. By the way, ive foud this very very interesting paper on the net, www.smartpropoplus.com/Docs/Walkera_Wk-0701_PCM.pdf very interesting, it explain with high level detail how the PCM on walkera WK-0701 works. Once i have finished this nasty cheap and dirty transmitter im working on i`ll post photos, and we`ll discuss it.
Posted on: 10/31/2007 2:37 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6563318
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
ive read a lot about this zhen hua, im still not convinced. The walkera #4 RX is just a normal negative modulation (that is, NRZ) PPM with 350uS mark timing and 300uS (non standard) - 1600uS space timing. besides the slight non standard timing, its a normal straightforward PPM. Perhaps some new Tx and Rx uses Zhen Hua, i wouldnt know, ive not laid my hands on those yet ( :(:( ). Ive a homemade TX with ATMEGA, and it works fine. However, its very interesting, [quote]The speed controllers shut down if any of these channels are above -25%. [/quote], ive not tried that one yet. Good one. Any electronic-hacking lover out there wants to join?
Posted on: 10/31/2007 10:54 AM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6562673
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
Hello!! yes, i`ve evolved since i posted this!!! The receiver needs 9 active channels to initialize, and then it just uses the first 4 and drop the rest. Ive still have not find out if channels 5-9 have any influence on GYRO-MIX-or whatever. Im currently developing a transmitter based on an old hacked JR F400, and a programmed ATMEL ATMEGA8 to do the whole processing (AD, PPM, etc). If youre interested, ill post some results (whenever i have them!)
Posted on: 10/28/2007 9:56 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=6551733
RE: Walkera/Dragonfly/Esky 4ch transmitter/receiver technical review.
hello! anybodie out there? this thread is a bit old, but i hope someone reads it.... im a somewhat skilled electronic engineer, and love RC. Ive recently bought a Walkera #4 receiver, just for the fun of it, and im still trying to make it work. everything ive read here seems to make sense... but still theres something missing. if theres anyone out there who can post an oscillogram of a walkera transmitter, so i can decipher it, it would be great. Ive programmed a pic and an HC08 to emulate an 8 channel PPM signal, but still nothing... anyone has a walkera transmitter, an oscilloscope and 2 seconds time? ill be grateful! and i promise to post everything i find out. thanks!
Posted on: 1/23/2007 2:15 PM by Author "e1000"
in the forum "Walkera Helis - Dragonfly, etc.."
http://www.rcuniverse.com/forum/fb.asp?m=5311096
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