Adding DSP or smart decoding to GWS receiver.

[Hovertime]

Most of you know GWS 4 channel receivers, and some of you know what a nice difference makes Digital Signal Processing, found in Berg , FMA receivers.
Few days ago I have stumbled upon this interesting project by Bruce Abbott , where GWS receiver gets brain update, using some solder fumes;) and PIC processor.

Anyone out there that built it? Do you like it? is it worth it?
Takes a brave soul to rip out factory processor and replace it with home brewed stuff :D

Here is the link, oh and remember to check other cool projects on that site.
http://homepages.paradise.net.nz/bhabbott/decoder.html

[Hovertime]

No takers?;)

[shoutchen]

the factory does not use a processor in the receiver bruce talks about, just a simple logic chip, just as in receivers over the past decade +


adding a processor like bruces ( others exist as well) add the capability to detect glitches, do failsafe, etc.

The capabilites of bruce's version is pretty well explained in the .asm file, and he seems to have recently updated it.


it certainly is wothe trying a 5 dollar mod to a 25 dollar rx, if you are into
trying some experimentation with electronics...


my 2 cents...


Steve H

[pldaniels]

I'm actually surprised that GWS hasn't picked up on this and actually implemented it into their product (with due royalties).

I for one will be doing this to all my GWS RX's as soon as I get a suitable PIC programmer.

Paul.

[Hovertime]

Yes, we would all benefit .... I wonder if Bruce Abbott has contacted GWS about that?

[pldaniels]

Would I be right in believing that this change would also make the receiver slightly smaller too?

Admittingly, a design change like this would cost whoever pays for it a lot of money, you just cannot go and rip up an existing product that simply. Perhaps someone can start offering a mod service? :-)

Paul.

[Hovertime]

I have PM'd link to this thread to Mr Lin, maybe he will get interested!
We should also pm Bruce.

[pldaniels]

Good idea - definately inform bruce - although bruce did offer the circuit into the 'public domain', I do believe that he may wish to have in return some recognition/royalty ($0.05 per receiver sold?) :-)

I'd love to see GWS incorportate this, I think it'd be a way of finally settling down a lot of the nay-sayers about the GWS receiver.

Paul.

[GWS4CEO]

Noticed your suggestion. Thanks.

Passed to GWS RD. I believe that you notice GWS Mark-II RXs?

[pldaniels]

I don't have any Mark-II RX's, do they have a glitch-filter like this in them?

Time for me to buy some more receivers (have to buy more pico servos too - oh the pains of flying :-)

I just flew my GWS B2 bomber today - was great fun ... http://www.pldaniels.com/flying/b2.avi

[Hovertime]

Haven't noticed any difference , except new label and shorter antenna with GWS 4P and 4PII ....
Since you are shopping for new receivers there is new kid in town - new generation of micro, dual conversion, DSP, crystal-less receivers - Sombra.

[pldaniels]

Do they offer 36MHz?

Biggest problem I've had so far is that all the nice upmarket receivers are for 40/50/72 type bands, nothing for 36MHz. Not that I can blame them, there's not a lot of people in Australia to buy 36MHz gear. Personally, I hope we get to use 72MHz eventually.

Paul.

[Acetronics]

Hi, guys

Sometimes ago, a friend of mine asked me for a failsafe system for the 4 first channels of classic PPM radios... and I wrote and designed a simple system ( PIC 16F628 ... Full from Full's !!! ) working like Multilex IPD systems.
This one permits also auto or manual recovery of signal ...

Anyone interested in ???

Alain

[FDC]

I'm interested. Could you please share your code and schematics with us. The posted info here was for a 4-ch receiver. How about making the DSP decoder section for 6 or seven channels instead.

TIA!
FDC

[PVenkman]

Do they offer 36MHz?

Biggest problem I've had so far is that all the nice upmarket receivers are for 40/50/72 type bands, nothing for 36MHz. Not that I can blame them, there's not a lot of people in Australia to buy 36MHz gear. Personally, I hope we get to use 72MHz eventually.

Paul.

The receiver is the Shadow 1; info I have was posted by the user Sombra (look at the 'Got Sombra?' thread on the Radios forum).

50/72/75MHz are all supported now (all in the same reciever, no less). In a message posted January 1 this user stated 'the 36MHz version is being worked on.... we will start sampling in 2-3 weeks.'

There's a Shadow 2 planned. 4 channel, even smaller/lighter, but otherwise the same features. I've not got one (yet) but all anecdotal reports are very positive. Similar in performance to the Berg rx's, which have an excellent reputation, but with the added benefit of fully synthesized frequency selection.

Here's a link to a vendor that carries this rx (I've no experience with this vendor so can't give any feedback on them at all). The manufacturer's website is still under construction.

http://www.dionysusdesign.com/Shadow1.shtml

[pldaniels]

I did check their WWW site out previously, while hunting around at various RX's. It'll be interesting to see if they come up with a 36MHz version (probably just a slightly adjusted 35MHz version).

Of course, the GWS RX's are still very nice for one reason - PRICE. I see their RRP is ~$17 USD, I don't think I've ever seen one in Australia though for less than $39 (about $29 USD) - ex crystal.

Paul.

[Hovertime]

Noticed your suggestion. Thanks.

Passed to GWS RD. I believe that you notice GWS Mark-II RXs?

Translation:
"In your dreams, and/or "real soon now" (in the nearest decade) " :D :rolleyes: :(

Oh well there are plenty of new and better DSP Digital Signal Processing receivers to choose from.

[pldaniels]

Anyone know if this could be extended to the 6ch receivers? Obviously a bigger PIC would be required, but the principle would be the same... surely?

[Mr.RC-CAM]

Anyone know if this could be extended to the 6ch receivers? Obviously a bigger PIC would be required, but the principle would be the same... surely?
Bruce Abbott uses a frame buffering technique. With a single PIC, four channels (or less) is all that is possible without degradation of the native frame rate.

RC-CAM

[Hooters Driver]

Could you send the signal to two separate PICs then use one PIC to decode the first 4 channels and the second PIC to decode the remaining channels?

[Mr.RC-CAM]

Could you send the signal to two separate PICs then use one PIC to decode the first 4 channels and the second PIC to decode the remaining channels?
For the least amount of trouble, the timing should be sync'd to the reset phase of the PPM frame. So, the first PIC could decode the frame, then it could I2C the data to the second PIC, that is used as a dedicated PWM generator.

Or, you could do what most DSP R/C makers do and use a decoding method that does not buffer the PPM frame (they do it in real time). However, I feel that the frame buffering method, if done wisely, can offer better detection of R/C signal problems.

RC-CAM

[Zlatko]

Hi All,
Bruce Abbott also has a 6 ch decoder on his site here http://homepages.paradise.net.nz/bhabbott/projects.html ( towards the bottom of the page ) for 16F630 . I haven't built any of them ( yet ) but the 6ch version also seems to have DSP .
Cheers

[Mr.RC-CAM]

Bruce Abbot also has a 6 ch decoder on his site... That version should solve the problem for those that need 6-Ch. It uses the post processing method and utilizes the timeslot where Channels 7 and 8 would normally go to PWM the six decoded channels. Three channels are sent at once, so it gets the job done in the short time that is available.

RC-CAM

[LT]

Hi, guys

Sometimes ago, a friend of mine asked me for a failsafe system for the 4 first channels of classic PPM radios... and I wrote and designed a simple system ( PIC 16F628 ... Full from Full's !!! ) working like Multilex IPD systems.
This one permits also auto or manual recovery of signal ...

Anyone interested in ???

Alain

Yes, more information please!

[KnimRod]

I'm going to give this a shot. I fly my Slow Stick in an urban area and often see minor glitches that can possibly be masked with this. Can anyone recommend a decent PIC development kit that covers a nice range of parts? I also have a project for my work that might be better suited for a small PIC processor. Most of my design experience is with full scale processors or microcontrollers. Thanks

[pldaniels]

Knim, there's no shortage of PIC development kits - I know my local 'retail electronics' store sells kits for them ranging from $40 AUD ~ $100 AUD. Of course, that's in Australia.

Paul.

[Acetronics]

:p
Hi everybody,

as requested, see attached files.

Few tricks:
Programming;
first run place JP1 jumper before power ON. Once programmed Unlock Fail-Safe ( see below ) and place jumper on if re-programming needed

place throttle stick to security position if manual recover requested; mid gas if auto recovery wanted.

take JP1 off
place it back

Place sticks to the security position ( the 2 sticks ) and take JP1 off.
gas stick has to be set to the same postion as for first step for manual recover !!!

- That's all, Folks !!!

Normal use:

after power on.

when manual mode: place throttle stick to security position to unlock the fail-safe.
auto-mode : gas servo goes to security position and follows stick as soon as signal is said good.

PIC programming:
HS Oscillator ( 20 Mhz ...)
NO Brownout

For some who absolutely need mods, source code is PicBasicPro ...

Alain

[Acetronics]

attachments ...tooo bad

[Acetronics]

PLS ...give me an address to post those documents ( 100 k is much too short ...)
Alain

[gedaso]

PLS ...give me an address to post those documents ( 100 k is much too short ...)
Alain

I can host the attachments on my website. Send me a private message if interested.

[bigandy]

:p
Hi everybody,

as requested, see attached files.

Alain

Hi Alain,

Would it be possible for you to email the files to myself please? That's if you cannot find anywhere to host them.

cheers
Andy

[KnimRod]

Well, I thought I'd give this project a go but my experience with PICs is very limited (I have extensive experience with microcontrollers). I purchased an ICD 2 module and PICDEM 4 board from Microchips only to find out that there are some fundamental incompatibilities with the 12F675 and these devices. I made a couple of small modifications to the PICDEM 4 board to route PGD and PGC to the correct pins (RBO and RB1) on the 12F675 and I can read the PIC properly now with the ICD 2 module. However when I attempt to program the decoder code into the 12F675, I get the following warning: MPLAB ICD 2 does not support programming this device if both the internal oscillator and internal MCLR are selected. You may continue programming, but you are encouraged to cancel, reconfigure your device, and try again. It programs and verifys okay but some additional text I found tells me: When Internal MCLR is used with MPLAB ICD 2 for programming, both Vpp and Vdd are powered together, and then Vpp is pulled high to Vihh to enter programming mode. This means that your code will be running before Vpp goes to Vihh. If that code makes use of port pins that correspond to Clock and Data pins in programming mode, there is a chance their values may not be 0, as necessary to enter programming mode. Therefore, the device could not be reprogrammed.

So the question to you PIC gurus, is the ICD2 2 not the appropriate device for programming the 12F675? What is? Thanks.

[Acetronics]

hi, everybody

files for 4 channel Fail-safe are here : http://www.sokoll.net/rcgroups/post_3210261/

many, many thanks to geoff ...

ah: for the PIC: OSC is HS and BROWNOUT is OFF !!!

alain

[RonD]

Haven't noticed any difference , except new label and shorter antenna with GWS 4P and 4PII ....
Since you are shopping for new receivers there is new kid in town - new generation of micro, dual conversion, DSP, crystal-less receivers - Sombra.

Just a little pet peave, in the interest of accuracy, the Sombra receivers do have a crystal, all receivers need an accurate crystal, its just that the one crystal works for all supported frequencies. A frequency synthesizer creates the frequency you want from the reference crystal.

[pldaniels]

Just out of curiosity - rather OT here - anyone know if there's a difference really between 35MHz receivers and 36MHz receivers? I've noticed that the top of the 35MHz spectrum is very close to the bottom of the 36MHz spectrum used here in Australia.

[Acetronics]

:D

Just a little 1/25 th of turn on the coils cores ... even if it is really done !!!

that's the same for 40 and 41 Mhz in Europe ...

Alain

:D :D :D :D
:p

[pldaniels]

Alain,

Yes, I beleive it's France which has the 41MHz spectrum. Well, I guess one way to find out is to buy some 35MHz rx's and try :-D I might get a low channel on the 36MHz band "just in case", rather than the high channels which I'm working on right now.

Paul.

[Hovertime]

So has anyone tried to add this chip to GWS receiver yet?

[Acetronics]

:o

Hi, Hover

Which chip ???

Alain

[Hovertime]

Exactly;)


The one this discussion is about ;)

[charles0198]

I am intending to process a complete PPM frame rather than decoding the channels and will use 4015 shift register for decoding. Does anyone knows such implemetation otherwise I have to go thorugh Bruce code and modify that.

I think this way I can save lots of processing time for the PIC and will be able to decode full 8 channels.

[Acetronics]

:)

Hi, Hover

I do not understand ...B.Abott writes in its soft lines for 12F675.

Where's the problem ???

Alain

[pldaniels]

Question: will it be feasable to make a DSP chip with a PIC for the GWS 6N/II receivers?

I ask because the 4P/II's just don't offer enough range even with a double-length antenna.

Paul.

[Hovertime]

Alain-no problems at all:) Just patiently waiting to see if someone did it, and if they liked it.

Paul-something is wrong with your system-I used to fly at least 1500 feet away with 4P receivers ( brushless slow stick for aerial photography) Castle Creations says they will have new berg 4 chanel receiver thats cheaper than current berg 5, price/performance wise its better choice than GWS 6CH....

[KnimRod]

I'll let you know on this mod early next week. I've programmed the part and I'm taking the rx into work with me tomorrow so I can use the stereo microscope (my eyes aren't what they used to be). I did vary somewhat from the original instructions in that I completely removed the 74HC164 from the PCB. My rx has the vertical connector pins so I have a little less room to attach wires. With the 164 removed, I can solder small wires directly to the pads. The DIP4 socket just barely fits between the xtal and the connector.

[Hovertime]

I was thinking about a way to protect wires from vibration caused braking ... Some shoe goo?

[pldaniels]

Hovertime,

I'll have to get things checked out - obviously /something/ is amiss. I'll do some long range antenna down testing, perhaps the rx pot is just out of wack.

[Hovertime]

I don't think 4P receivers have anything adjustable...?

Also-range on the ground is much shorter than in the air:)

[pldaniels]

I'm having range problems with the 6N/II. As you can see from the picture there are two points of adjustment... the question is which one to adjust.

Paul.

[Hovertime]

Paul - you might want to look at this thread about tuning receivers:http://www.rcgroups.com/forums/showthread.php?t=304847

[Acetronics]

:D
For those who like transistors, here is the elder of the "4015 type" decoders...one more time Thanks to F.Thobois !!!
note this had been used on 6 Ch. decoders to fit LM1872 mini Rx with a 74 HC 164 wich works well too...

oldies ...but seems really goodies
:p
Alain

PS: I'll try to move my 4 Channels fail-safe system to a 12F683 chip w/ serial input data ... seems more than possible to me, isn't it ???

[pldaniels]

Paul - you might want to look at this thread about tuning receivers:http://www.rcgroups.com/forums/showthread.php?t=304847


I actually read this a while ago and was planning on doing the servo-jitter test today after I've woken up a bit more - naturally I'll be marking where the RF coil is /currently/ set.

Thinking about the earphone test method, I was thinking of perhaps creating a small expanded-scale voltmeter with servo lead to give a more 'accurate' (??) reading of the strength.

Paul.

[JMP_blackfoot]

I'm having range problems with the 6N/II. As you can see from the picture there are two points of adjustment... the question is which one to adjust.
The RF coil is in the upper left corner of your picture. Don't touch the other one (discriminator coil).
You can also simply try adjusting at a distance where the servo starts jittering, and turn the coil slug for minimum jitter (transmitter antenna down of course).

[pldaniels]

Thanks JMP.

[Acetronics]

:rolleyes:

Hmmm...
Do not forget to use non-metallic "screw"drivers and to keep hands and body as far as possible from the Rx board.A non-metallic table is also required !!!

ceramic drivers are THE thing.Plastic ones the minimum.

a good trick is to load the Tx with a 6v 0.1 Amp bulb in series with a 47-100 pf ceramic capacitor ... connected between aerial base and batt ( or case )ground.
This makes a load to the Tx output stage, and protects final transistor from overheating ...

Alain

[pldaniels]

Alain,

Oh my oh my - that's such a hack *laugh*. Takes me back to the days of CB radios when we were trying to maximise output of the TX using such tricks... even using flourecent tubes against the antenna.

Sad news is that I've lost my RF slug screwdriver ... lost somewhere between South Africa and Australia :-( I'll improvise with a stick of balsa hardened with CA.

[Acetronics]

Another thing is to look w/ a scope at the signal on the "signal pin" of the battery connector ...one oftens finds there something interesting to help tuning the Rx ...
Here, bulb is just to limit the field stength ...or , on the field, to verify Tx sends something !!!
Oldies are sometimes useful ...
Alain

[pldaniels]

Alain,

I have to agree - a lot of 'oldies' (hacks ;-) are excellent.

[KnimRod]

Regarding the original topic, I did manage to modify a GWS 4 channel rx using this smart decoder. I haven't flown it yet but it appears to work fine. I did hit a stumbling block early on though... With the GWS Futaba/Hitec shift rx, the pulse stream from the TA31136 demodulator is negative shift but it's inverted by the data slicer before it hits the decoder, effectively making it a "positive shift" for the purposes of decoding. So for all GWS receivers, the "shift" will need to be considered "positive" when decoding.

[pldaniels]

I just replaced my 50cm GWS 6N antenna with a 104cm (1/8th wavelength on 36MHz) antenna and wow, what a difference. Previously the servos would start spasming at about 30m through 5 concrete walls, now I can go completely outside of the house along the same line of direction and I only have very minor quivering.

Paul.

[Hovertime]

Here is another option for GWS receiver upgrade - DSP chip with RC-Cam software : http://www.rcgroups.com/forums/showpost.php?p=3229968&postcount=9

[pldaniels]

I really have got to get myself a PIC programmer and assorted money-wasting things :-P

There's just so many cheap RX's out there that could be turned into something more reliable with a $5 chip that it keeps me from sleeping at night :-|.

Paul.

[saitrix]

So does making the receiver antenna help for the GWS rx's?

[Mr.RC-CAM]

So does making the receiver antenna help for the GWS rx's?My opinion is that making the GWS antenna "better" ends up causing more glitches. You will get more range in a perfect environment, but for some folks that will also translate to more glitching issues.

To see the impact of antenna length on the GWS, just read this: http://www.rc-cam.com/ant_exp.htm

RC-CAM

[pldaniels]

I put a 1/8 wavelength on a GWS 6N the other night, it definately helps with the range. I'm fortunate that out here there are perhaps no more than 4 or 5 R/C modellers in the whole town, each flying in a distinctively different location (due to differing planes).


What I am wanting to do though is check that the existing antenna didn't have a break or something in it as the range was disasterously short (100m).

[saitrix]

Have anyone of you tried a ferrite ring between the esc and the gws rx? I am getting problems from 2 gws rx's so im trying to get them working well. I am getting a stupid range of about 60-70 metres with the R4PII, not sure what i can do as i dont have a PIC programmer :(

[vintage1]

If youy want some (inline) RF chokes I have a few for sale. You could insert them in the power leads from the ESC with some suppressor caps between + and - and see if it helps.

I.e. a full 'pi' filter.

If trash is coming in that way, that should sort it.

[saitrix]

Not sure what you exactly mean? Would i just be able to try a ferrite ring first or does that do something different?

[pldaniels]

Since we're talking about GWS receivers... I was range testing one today and the motor would glitch/spit everytime I used either rudder or elevator - anyone know the cause of this? It started happening at about 30m out with the antenna collapsed.

Paul.

[saitrix]

Maybe the servo is causing the glitch? It could be picking up the noise from the motor inside it.

[pldaniels]

hmm.... that's a thought - wonder how I could alleviate that. Well, I've picked up a GWS dealer certification now, so I can start buying their gear in bulk so I'll check to see if any other 6N/II's are suffering similar issues - I get the feeling that I've got a dud RX here because another one that I've used (which alas is 2400km away) didn't give me any such troubles.

Paul.

[kfong]

Have anyone of you tried a ferrite ring between the esc and the gws rx? I am getting problems from 2 gws rx's so im trying to get them working well. I am getting a stupid range of about 60-70 metres with the R4PII, not sure what i can do as i dont have a PIC programmer :(


A PIC programmer would be easy to make, lots of circuits on the web. We made the Tait version. Works fine with ICPROG.
http://www.embeddedtronics.com/pprog.html
Circuit is online if you wish to make your own.

Kin

http://www.embeddedtronics.com

[Hovertime]

Looks like this one uses parallel port , which does not work with win200/xp.

Pdaniels-this can also indicate a bad servo, 30 meters (yards for imperial users;) ) is pretty good for a range test, isn't it?
As RX starts getting weaker and weaker signals it picks up all it can, in this case-servo noise.

[Xnaron]

Wow very cool... I am a programmer with an electronics background. This looks like a great project. Can someone point me to a good pic programmer that I can buy online that will program this type of PIC? I'd like one that would work with XP.

Thanks,
Brendin

[Hovertime]

Brendin - you may want to read this : http://www.rcgroups.com/forums/showthread.php?t=217886

http://www.sparkfun.com/tutorial/Programmer_Selection.htm PIC-PG2 costs about 13$ (search for "pic programmer" on ebay-someone sells these with free shipping for example http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4661&item=3872016652)

These do not work with laptops according to Sparkfun.

I have bought mine (as a kit) from these guys, http://www.rcgroups.com/forums/showpost.php?p=3229582&postcount=73 mine is improved version with in circuit programming, and works with HP pavilion laptop, which otherwise HAS problems with other serial stuff such as FMS serial interface:)

[saitrix]

I didnt realise how cheap PIC programmers were! Ill have to get one i think. So what do people think to the GWS rx's after this has been done to them? Also will it work with the GWS R6NII?

[pldaniels]

What I'm wondering is if you can just use a 4ch decoder for the first 4 channels on the 6N/II .... or doesn't that work either?

Paul

[saitrix]

Yeah i would like to know that alos as that would be perfect for me.

[pldaniels]

I "theoretically" cannot see why it wouldn't work. The main reason I'd want to use a 6N/II is for the extra range it offers over the 4P. If that doesn't work out - then I'd probably carry on getting Jeti 5 REX receivers.

[saitrix]

You sound exactly like me! I originally used the GWS rx then my Formosa crashed due to glitching of one so i bought myself the Jeti REX 5 and i have been using it ever since, i would love to get my GWS rx's working well as they are just so cheap!

[pldaniels]

saitrix,

I'll be ordering a couple of 6N's to modify myself and see how things go. They're cheap enough that you can afford to blow one or two in order to reap the long-term gains.

Paul.

[saitrix]

Well if you do that then keep me up to date!

[charles0198]

I am ineterested in PPM frame processing rather than decoding. I haven't studied Bruce Abbott's code yet... could it be possible to modify that code to process the frame with the same features?
Can somebody gave me a brief algo of the Bruce Abbott's code... it seens to be quite lengthy!

[Mr.RC-CAM]

I am interested in PPM frame processing rather than decoding.That is really the same task. Even if you use an adjunct IC to communicate to the servos, the fundamental code is about the same.


I haven't studied Bruce Abbott's code yet... could it be possible to modify that code to process the frame with the same features?
Yes, but full frame processing presents some difficulties for simple implementations. With a 8-channel PPM system, you will be challenged with having to output all the channels in the "free" time after a valid frame reset. That is if there is any time to spare. In some cases you will have only a couple mS that you can utilize. From my experience, bit banging several servo channels at once, with a typical low pin count PIC, will result in substantial servo jitter and low step resolution.


Can somebody gave me a brief algo of the Bruce Abbott's code... it seems to be quite lengthy!He gives a very good description of the code on his web page and in the commented header in the source code. Just take a look at it. His PPM validation algorithm is essentially limited to range testing the channel pulse widths. The final servo pulses can be from the current frame, from the previous good frame, or default to the stored failsafe positions. It depends on the PPM validation results. There is some data averaging too, but I do not like that since that sort of thing can behave a lot like a reduced frame rate. I suspect he had to do that to reduce some servo jitter.

RC-CAM

[Hovertime]

Thanks, very nice explanation in "plain words" :)
Could you give similar short description of your DSP code? And the reason for better PIC? Benefits?

Thanks a bunch.

[Mr.RC-CAM]

Could you give similar short description of your DSP code? The ongoing DSP4-SC discussion on eZone gets into what the new firmware can do. But, how I do it is a secrete. :)

http://www.rcgroups.com/forums/showthread.php?p=3278171#post3278171

Please keep in mind that it was designed to solve my Plantraco DSP4-SC problems. But, it can be used with many other legacy Rx's. It is currently limited to four channels.


And the reason for better PIC?The PIC12F683 has additional hardware features and faster code execution. It supports interrupts, has three timers (one of which is 16 bits), hardware PWM for the ESC feature, and a internal 8-MHz Oscillator (which really helps). It also has EEProm, which is utilized to store some prior use frame data for fast power-on startup times.


Benefits?That is also discussed in the other thread. In summary, 1uS servo jitter, 10-bit servo resolution, failsafe pulse flywheeling, autoshift detection, >512 step ESC. PPM fidelity is exceptional and so there is no need to signal average.

The firmware is currently running the "PPM engine" in my Lama-XRB R/C helicopter project, with a cheap GWS PICO Rx under the hood. Even in terrible conditions, I have yet to see a glitch or a hint of bad behavior. I am very proud of the Lama project (my favorite hack to date). The details to this project can be seen here: http://www.rcgroups.com/forums/showthread.php?t=326670

I would rather not say that what I have created is better than the other personal DSP upgrade offerings. It just represents what I believe is important in a decoder design. At this point I consider the decoder a beta release since it needs extensive field testing before I will be satisfied. Ezoners can take adavantage of this by using my free win-win offer discussed in the Plantraco thread.

RC-CAM

[clively]

oops. wrong thread.

[saitrix]

Does that mean if i get that one you have programmed and just hook it up like on the link erlier on the thread i could add dsp to my GWS R4NII?

[pldaniels]

saitrix,

That is correct.

[pldaniels]

Just to let you all know - I've just put in an order for 10 4P's and 10 6N receivers (I'm a GWS distributor now) so you can expect to hear some popping/frying noises as I try to mod a couple to see what happens.

Paul.

[Happy|Harry]

does anyone have a schematic for the R4N as my pic's have arrived (thanks rc-cam :cool: ) but i need to find the correct connection point for the ppm in

phil

[Hovertime]

Lets just use this thread for GWS receivers Phil;)

As RC-CAM suggested in another thread try a pin #10 on the MC14014B chip.

[Happy|Harry]

ok here we go then adding mr rc-cam's dsp chip to a GWS R4N V1 rx :), i'll post some pictures later of the connection points but for now here's some pics of the pre-dsp R4N.

phil

[Mr.RC-CAM]

The PIC's Vcc & Gnd should come from the MC14014B's power pads. This is a low current regulated voltage -- should be about 3.5VDC to 4.0VDC. Servo power would continue to come directly from the unregulated battery supply.

In your final installation (after you find that the PIC hack works), add a .1uF ceramic cap directly across the PIC's power pins (use short cap leads). Also, do your best to minimize the length of the PIC's power leads.

The pinout to the DSP4-SC upgrade PIC is found here: http://www.rcgroups.com/forums/showpost.php?p=3229968&postcount=9

RC-CAM

[Happy|Harry]

thanks rc-cam the voltage from the power pads is 3.3V and everything is installed but unfortunately pin 10 on the MC14014B is not the ppm signal as i'm getting zero response from any channels(and i don't fancy soldering to each pin 1 by 1 :eek: ) or is there a way for me to trace it with a standard multimeter? i have no ceramic 0.1µF caps on hand but i have some tantalum bead in that size that i'll use instead

phil

[Mr.RC-CAM]

A voltmeter will not help you at all. You need an o-scope.

Are you sure that the Rx uses a MC14014B? From what I can see in the photo, it does not seem like that is the chip that is being used. Although I cannot see the part number on the decoder IC, the copper traces suggest that it is a '164 part.

Please post a close-up photo of the IC so that I can see the ID on it.

RC-CAM

[Happy|Harry]

the print is too feint to show up on camera but looking again it seems like i made a typo :o, it's actually an MC14015B

phil

[Mr.RC-CAM]

... it's actually an MC14015BIf Pin 1 is the pin that is in the upper left corner (ref your second photo), then it is the PPM input. Otherwise, the PPM input is at Pin 9.

RC-CAM

[Happy|Harry]

yeah pin 1 is upper left and thanks for the help!, i'll have some pics of the install tomorrow

phil

[Hovertime]

Any progress Phil?