Microprocessors for control IR or FM?

[peterbennett26]

Is the new JMP 4 channel system done with a single PIC? & which one?Rather posts seem to indicate that it is offered as an add-on (@Bob Selman) to existing boards rather than being a single board solution. Is it possible to do this as a DIY project to save cash and weight ? Do any web pages describe the implementation of this systems and the Ztron (RRFS100?)?

[clipclop]

Peter,
The micro's are used to decode the signal after it is received and demodulated by either an AM RX , FM RX or IR RX . most common micro is the 8 pin pics and it depends if they are servo output or actuator out put decode as to how many channels can be obtained fron a single pic I think up to 5 servo outputs can be had from the 8 pin but only 2 actuators pluss motor control as the actuators take 2 output pins each , its easyer to piggyback an extra pic for more channels than reconfigure the PCB , it may also be lighter . the next size pic has 14 pins so naturally eats up much more space .
Stewart

[peterbennett26]

Stewart,

This might be a daft question :- Are the chips physically placed on top of one another? Is this how the Didel Mim4 works also? It seems to have 14 pins. Whereas the JMP shown on Graham's site has a 16 pin IC (might not be the PIC ? it has the id code 83361A19)

Thanks,

Pete

[shoutchen]

the 83661 is a toko tk83661m, a narrow band fm ic that replaces the older motorola mc3361, and is usefult to higher frequencies...

Not a PIC



Steve H

[JohnnyB]

Steve,

Which chip is the PIC, (see below) ?

Thanks,

Johnny

http://www.rcgroups.com/forums/showthread.php?s=&threadid=194694

From Mario's forum:- JMP's response.

Re: JMP [ 4 ]


quote:
--------------------------------------------------------------------------------
Originally posted by peterbennett26
How does your JMP system differ from the systems discussed in the IR and AM thread (indoor models).
--------------------------------------------------------------------------------

My system is FM narrow-band, i.e. it allows flying several models simultaneously. Also it is not DIY.
quote:
--------------------------------------------------------------------------------
Do you also use PIC programming? Do they work with a radio signal? an IR signal or both?
--------------------------------------------------------------------------------

I use PIC programming. The same PIC could obviously be used with IR.
quote:
--------------------------------------------------------------------------------
Have you posted details of the system anywhere?
--------------------------------------------------------------------------------

Details can be found on the site of Bob Selman Designs.
quote:
--------------------------------------------------------------------------------
4th channel seems to be offered as an ad-on (with increased weight). Can it be done on a single board?
--------------------------------------------------------------------------------

Yes it can be done, but it seems that it hasn't been done yet. By the way, the extra weight of the 4th channel add-on board (albeit without wires) is 0.24 gram.

Happy flying.

[clipclop]

Johnny,
I think the pic is on the other side of the board on the JMP reciever . It is none of what you see .
Stewart

[peterbennett26]

This system looks small enough for our purposes. Has anybody any information on the chips employed?



Also has anybody got a good link to a clearly described application note for using these chips or similar in model radio control? A suitable aplication note would be quite good, as they usually give you a typical circuit, sometimes even a pcb design.

Pete

[JohnnyB]

Pete,

I can't help with the ID of the components, but here is a clearer shot of some of the ICs. NB The shot is from an advert ,I don't have the system.

[clipclop]

Peter,
The pic can be just attached on top of the orriginal pic but I would think they use a small PCB to aid connection of the outputs .
Im not familiar with that system , but studying the picture the pic chip is as marked.
Stewart
Note :- the pic is the last chip in the system it only decodes the signal for either actuators or servo output . the rest of the bits on the board are the receiver ,

[bselman]

These pictures are of the Ruijsink system. The receiver used the MC3371 receiver chip and a PIC12C508 decoder. The actuators were driven from the TDA7050 ics.

Bob

[peterbennett26]

Thanks for the info Bob. Which IC apart from the toko does the JMP use?

Pete

[peterbennett26]

Here's the new falcon receiver:-

http://www.rcgroups.com/forums/showthread.php?s=&threadid=196020

webpage
http://www.falconmodels.uk.com/acatalog/Radio_Equipment.html

Is this an all-in-one or does it need the other things such as dc-dc, esc, bec etc.

Do the white caps serve a function or are they to hide the ICs employed? Any info on ICs employed in this design?

For some info on microprocessor coding (but 8051) here is a thread where they are using Cygnal ICs for a single 'servo' heli

http://www.rcgroups.com/forums/showthread.php?s=&threadid=99568&perpage=15&pagenumber=1

this is the example code from Rolf (Gulsmed)

[clipclop]

Peter ,
The white caps are crystal filters needed to obtain narrow band reception , design and construction of FM receivers at the scale of the falcon and other miniture RX's is a dificult task , requireing a good set of test and measurement equipement and a sound knoledge of electronics . My hat is off to the acomplishment of those people .
You also seem to be under the impression the micro-processor does the reception , it does not , it only decodes the signal for the servos etc after it is demodulated from the RF carrier .
Stewart

[peterbennett26]

Stewart,

Thanks for your clarification.

Is the falcon receiver 'just' a tiny radio receiver that does no further processing of the signal then? I understand that that in the transmitter the information is added to the carrier wave, and the actual signal is encoded by small variations in the frequency of the carrier wave, (FM). On the JMP there seems to be a couple of minature toko style coils (which can be tuned to give the required band selectivity for the carrier wave?), instead of the tiny crystals on the Falcon receiver.

Thanks,

Pete

ps. I have the components for a dip meter and an absorption wave meter which can be used for tuning coils etc. along with a 2/3rds built multi-band transceiver for QRP ham radio. My trouble is forgetting what I once knew and not enough time to do everything.

[clipclop]

Peter,
The falcon will have a pic or some other microprocessor to decode the signal , there is obviously more components on the back of the board , some not all Rx's use RF chokes instead of actual coils as part of there rc circuit the tuneing is fixed . A dip meter will need to be very sensitive as the components in the rc circuit's of these receivers are very small so the energy absorbed will also be small , most dip meters would problly be deaf to these sized components .
Stewart

[micromicro]

here is the back side of JMP (from Mr. Bob Selman's site) don't know which PIC he uses.
the two white square blocks on Falcon are the Ceramic filters.

[micromicro]

and a micromag closeup
note that falcon and the micromag uses the same ceramic filter

[peterbennett26]

Micromicro,


I can recognise the tuning coil on the micromag but I'm not familiar with the component at the bottomm right hand corner. It looks like it has heat sink fins, surely not a mini varicap?
Can you read the code on the (receiver?) IC of the micromag? What is the full code on the ceramic filter?

Thanks,

Peter

ps Are there any other ICs you can identify?

[peterbennett26]

Stewart,

Thanks for saving me some wasted soldering iron time. If I manage to cobble one of these together I will leave the alignment to a mate who has the fully digital gear for receiver stage alignments.

Cheers,

Pete

[JohnnyB]

Here is a french system from

http://www.microplanesolution.com/index.htm

sorry the resolution is so poor again it is an advert

[JohnnyB]

The above is the combo. This is just the receiver:-

[Graham Stabler]

Beginners guide to blobs on an RX:

Long black thing: IF chip, does all the mixing amplifing and detection
Short black thing: Genrally an 8-pin pic
Small white blocks: These can be either the ceramic filters or a ceramic descriminator.
Small silver blocks: Will either be a crystal or a filter.
Things with knobs on: If the receiver does not have a ceramic discriminator it has a quad coil and capacitor for the detection, one or both will be adjustable.
Small things with knobs on, sometimes used to tune the input filters to the correct band.

Others: You can see charge pumps on the RFFS, voltage regulators on others, mosfets both single (3pin) and dual (6pin) for actuator drives and other mosfets for motor control from 6pin to 8.

On the subject of the thread: not with an 8pin pic.

Graham

[micromicro]

peter,
the receiver IC of micromag is the mc3371 from motorola which is discontinued and the TOKO 83361 is an pin to pin replacement for it.
the filter is the Toko AECFM3 type.
the component at the bottom right hand corner is also a tuning coil/inductor for adjusting/tuning the antenna.
the IC at lower left hand is the TDA7050 which is an amplifier but latest RXs are using mosfets instead of them.
there is another TDA7050 on the other side along with the MC3371 and a specially manufactured SMD crystal.

in the attached pic of the JMP rx the white square with C49 written on it is the ceramic discriminator which is used instead of the Tuning coil (the metallic case one) on the micromag.
all these are the circuitary required for proper operation of the 83361 or 3371
a look at the TK83361 's datasheet might make few things cleare

[JMP_blackfoot]

Originally posted by Graham Stabler
On the subject of the thread: not with an 8pin pic.

If the subject of the thread is 4-channel, it is perfectly possible to make a 4-channel (three actuators and one ESC) receiver using an 8-pin PIC. The pin allocation would be like this :

2 pins for supply
1 pin for signal input
1 pin for ESC mosfet drive
1 pin for actuator common drive
3 pins for actuator individual drive.

The price to pay for such a scheme is that the drive to the actuators will be 0 to 50% instead of 0 to 100%, and the on-board mixer feature will be lost.

The JMP Combo receiver can be modified for 4-channels in this manner, just by changing the software in the PIC. Hardware remains exactly the same.

[JohnnyB]

JMP,

Can you explain why it would only drives the actuators to 50 %. Is the common actuator pin, sort of like a ground for them. Does the other PIC drive to minus volts using this common pin? thus creating say minus 5v to plus 5v

Thanks,

Johnny

[JMP_blackfoot]

Originally posted by JohnnyB
Can you explain why it would only drives the actuators to 50 %. Is the common actuator pin, sort of like a ground for them.
With the 4-channel software, one pin outputs a constant 50% PWM; it is connected as the common pin for the 3 actuator coils. The effective voltage at this pin is thus 1/2 the supply voltage. The individual actuator outputs are centered at 50% PWM (50-50 = 0), they can go one way to 0% (50-0 = +50%) or the other way to 100% (50-100 = -50%).

[peterbennett26]

Another role for the PIC? pic + Fet

"The controllers which switch off the motor rpm at voltage below 3V, to maintain correct receiver and servo functions and to make sure one Li-Polymer cell will not be deep discharged."

"Safe Start with receiver signal check. 64 steps resolution from zero to full throttle (1,15ms to 1,85ms). The upper part of the throttlecurve is spread in order to ensure a linear control behaviour of the controller."
This seems to be the lightest available, YGE3,does anybody know the basic algorithms (typical code) and how they work?

Thanks,

Pete

ps I am right in assuming that this is already built into the decoding PIC in the earlier examples, i.e. these are working on the deconvoluted radio signal?

If that is the case, can we protect our lipoly batteries by altering the code?

[JMP_blackfoot]

http://www.math.niu.edu/~behr/RC/speed-ctl.html

[Graham Stabler]

I was assuming most people would like to use their actuators to their full potential otherwise you are carrying dead weight.

Graham

[JMP_blackfoot]

Well, people used to do it with the first version of RFFS100...
Could be a simple solution for a scale model ?

[peterbennett26]

A nice piece on a receiver based upon the MC3372 chip can be found here :-
http://hem.passagen.se/communication/receiv.html

Quad coils and crystal filters are also nicely explained

The MC3371 MC3372 needs a Murata CFU455D2 or equivalent crystal filter 455 is the frequency centre (455 Khz) and the D designates the +/-10 Khz band pass at an attenutaion of 6 dB.
Alternative crystal filters are BLFC455D (toko).

CDBM455C49 is the ceramic discriminator to use for the MC3361. This can be used instead of the quad coil, e.g. 7MC-8128Z or 7MCS-13456Z.

Pete

[peterbennett26]

http://home.nordnet.fr/~fthobois/rx22.htm

[JMP_blackfoot]

This is a great little receiver, with full range performance. Just one point : it may be a little sensitive to electrical noise, in which case the discriminator coil L3 should be kept shielded (just do not discard the original shield). That is our experience with this receiver which has given good service.

[peterbennett26]

JMP, (or anybody skilled in the art)

Is it possible to minaturise further the RX22 circuit by using direct substitution with SMD components and smaller toko/murata quad coils and crystal/ceramic discriminators etc.?

[peterbennett26]

This is the current layout

[peterbennett26]

The current PCB layouts and codes can be found here :-

http://home.nordnet.fr/~fthobois/annonces.htm

however, have a look at the circuit corrections :-
http://home.nordnet.fr/~fthobois/infos.htm
RX21
Une INCROYABLE erreur !!
A l'occasion du dépannage d'un RX21 monté par un ami et qui refusait de fonctionner, nous avons constaté
que si le 145170D recevait bien le 10245 kHz généré par le 3362, il ne l'exploitait pas et de ce fait était
inerte ! Un examen attentif du montage nous fit découvrir l'erreur ....... du circuit imprimé :
>>>> Le 10245 n'attaquait pas l'entrée de l'ampli du 145170 ( picot 1 ) mais la sortie ( picot 2 ) ! <<<<
Cette grossière erreur commise par l'auteur n'avait pas empêché les RX21 fabriqués jusque là de fonctionner ..... et c'est bien cela qui est incroyable !!
Nous vous conseillons de faire la correction très simple, pour remettre les choses dans l'ordre, même si
votre RX21 fonctionne parfaitement.

[billystiltner]

Originally posted by peterbennett26
My trouble is forgetting what I once knew and not enough time to do everything.

Aint that the truth.

Tothe subject- a quote from Michael Shantz

"Chipcon CC1010. It is a transceiver and 8051
microcontroller on one chip."


Billy

[JMP_blackfoot]

Pete,

What about you start a new thread where it belongs ("Modelling Science") and rename it "Basics of micro receiver design" ?
Good luck with your work.

[JohnnyB]

Billy,

Sorry to show my ignorance.

Who is Michael Shantz, is he the designer of the Falcon micro-receiver? Does your post mean that you think this (CC1010) is being employed in some micro-receivers, or that it might be useful for this purpose?

:confused:

Johnny

[billystiltner]

Michael Shantz is a guy that posted some messages on another group about micro recieivers and processors to use in them.
He has a website. You might be able to google it. He has built his own rxs from scratch. It is not ignorant to not have heard of someone or what they might have said. I was only quoting him because it is where I received the information from.
I have no experience with the Chipcon chips.

Billy

[JohnnyB]

Re JMP explanation :- What happens when you have two Pics.

One line - I was thinking of the add-on boards, does that still only drive to +/- 50 %, but just adds another channel? Are all in the pins parallel wired, but the second PIC is looking for the fourth pulse in the PPM signal?

If you did not not do this as an add-on, but you start off with two pics, is it possible with these to go +/- 100%. So the zero volts position is stick centred, one PIC does the pulses greater than 1.5 ms and the other less.

Would this be less 'redundant' weight ?

[JMP_blackfoot]

An add-on board leaves the outputs 100%.
The one-PIC, 50% solution is a (clever ? nobody else seems to like it ) trick to get 3 actuators driven from the 4 available pins of an 8-pin PIC already installed on an existing receiver.
You could use 2 PIC's, one for an ESC and two actuators (100%), the second one for up to two actuators (also 100%), but a "cleaner" solution is a single 14-pin PIC such as the 16C505 (if migrating from 12C508/509) or 16F630 (if migrating from 12F629), which will take up less board space. Of course a new software must be written.
It would be difficult to use one PIC for each direction, because you must keep a measure of synchronization between the two.:

[JohnnyB]

Sorry JMP, I thought your 3 channel board also used the 50% method for the central stick positions.

Johnny