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May 25, 2006, 07:50 PM
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Thanks Malc. I am thinking of trying to start a new thread in DIY and try to find guys with PIC programmers in the bay area, just because it will be faster. If not, then I'll gladly pay your charges and get it from you.
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Jul 07, 2006, 01:33 AM
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Malcolm & Mark,
Is this build for Alessio & Andrea's RC Joystick NG or NG2?


Jul 07, 2006, 04:51 AM
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Thread OP

Its niether. We took Alessio and Andrea's original 4+12 code for the 18F2550, and then we (well mainly Mark) modified the code to give 8 fully proportional inputs.

Later Allessio developed and released the NG2, presumably inspired by our efforts
Jul 07, 2006, 07:42 AM
Registered User
Thread OP
Allessio posted the following, I thought it should be part of this sticky so here it is

Originally Posted by alessio70
if someone is interested we have released a new version of our RC Joystick NG^2 that now support PCM signal for some radios. Many thanks to Shaul Eizikovich (author of SmartPropoPlus ) that has suggested us to include PCM, given infos on PCM and sent PCM soundcard recordings for testing it (we haven't any PCM radio :-) ). PCM support is limited for now to Sanwa/Airtronics PCM1 and PCM2.

You can find the project at:

clicking RC Joystick NG^2 you'll be redirected to the last release of the project.

Main features summary:

- flash pic: can be programmed more than once

- two joystick instead of one for a total of 8 analog axes (with about 5000 points resolution each in case of PPM, PCM resolution (1024/512) in case of PCM) and 16 buttons

- joystick controls can be freely assigned by user to radio channels for the maximum versatility; these assignments are stored inside pic (non-volatile) eeprom and are programmable directly via USB with a software utility.

- few components and very small pcb (about 2x4cm, smt components)

- the project is totally free... on the site you can find the binaries, sources, schematics and layout of the circuit

require a radio equipped with a PPM output (buddy box connector) or PCM ( PCM support limited to Sanwa/Airtronics PCM1/2 radios).

ciao :-)
alessio e andrea
Jul 19, 2006, 11:38 AM
Heli Humbled Daily
Beautiful project! I just breadboarded it last night and was using my blade CX 4 channel remote with accuracy far beyond that of controlling PPJOY through the microphone port! My JR remote isn't working yet, but I think its because I need to use a mono minijack connector for DSC, not a stereo. Will pick it that up today and make an adapter to use both remotes.

I was unable to obtain the transistor that you use to mediate the PPM signal and LED output, and it doesn't seem to work with the alternate part I picked up (leads are switched and parameters slightly different, but I thought it should have worked...)

I know the PIC is working correctly because in my desparation I pulled all the resistors and LED and just connected the signal lead prom the tx directly to pin 21 of the PIC (ouch, almost 12 volts going to the lovely PIC!! thank goodness for free samples!) and BINGO, perfect signal (I only tried it for a few seconds).

I guess my question for you is, do you see any harm in just pulling the signal from the tx down to 5 volts with a Zenor 5V1 and connecting to pin 21 on PIC? The LED function seems snappy, but I will have the USB port plugged in behind comp and will never see it anyway, so I will probably leave it out. Would this affect the program of the PIC in any adverse way you can think of?

Jul 19, 2006, 12:49 PM
Registered User
Thread OP
Hi and welcome to RC groups. Which project did you breadboard, the one contained in the zip file in this thread, or the one from Allesio's website ?

In the original one discussed here, the transistor used is a general purpose NPN type and should be readily available from most suppliers. If you are having issues with obtaining the transistor, simply locate a low noise NPN alternative with similar specifications

I'm not 100% sure pulling the TX input down to 5v using a zenner will work without doing any damage to either the TX or the interface. If it works and you get good results then post a modified schematic and share your findings
Jul 19, 2006, 03:32 PM
Heli Humbled Daily
I used the schematic from your zip, but the ground/VCC are rather confusing... at one point the VCC from transmitter and USB come together, which would not work at all... That's why I always like schematics that just refer to a common ground and differing Vcc. No complaints, though... yours is great, I would have gotten nowhere without it.

For the transistor, I found almost identical, Vceo rated at 50 Vdc instead of 45, which should work fine. Maybe I'll try again when I have some time.

Essentially what I have done now is pull the signal from the transmitter with a 1 K resistor and some other resistors in circuit to pull the voltage down to something safe for the PIC (~5volts), although it seemed to take the 12 volt signal without burning (18F series are much tuffer that 16F!) I then send that signal directly to PIN 21 on the 18F2550. The LED is removed from the circuit.

I think it could be easily done with a Zener diode such as SIMPIC does it:

So basically, everything in your schematic for the PIC/xtl/USB side, but on the tx side, just take the signal directly to PIN 21 with a safe voltage for your precious PIC and bypass the LED/transistor. Your code works like a charm with that setup!
Jul 19, 2006, 05:59 PM
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Thread OP
I've built one of the SIMPIC interfaces in the early days when I was searching for a decent USB interface for use with sims and games, so I can confirm that it works, well it did with my sons Futaba TX and my JR 3810 ! - my only concern would be if the diode clips the PPM signal at all... maybe using one of the windows sound card based scopes would provide details on what signal is being fed to the PIC on PIN 21 to see if there is any distortion of the signal at all ?

Thank for the suggestions for making a simpler interface... maybe others could try it out and post their findings, and even come up with a revised PCB ??
Jul 19, 2006, 06:47 PM
My member is not
Zlatko's Avatar

Bruce Abbott has a "trainer cord translator" ( Futaba to JR etc ) which uses zener diode and resistor to clamp voltages.

Hopefully Bruce can comment on how well the method works.

darkith uses resistor network for his IR and UHF TX modules ( if I remember right ), hope he can comment as well.

Jul 20, 2006, 11:13 AM
Heli Humbled Daily
I boarded Alessio & Andrea's RC Joystick NG2 last night, and it also uses a 5 volt transistor to pull the signal through to pin 21. It works fine as long as your signal from the tx is not pulled to the 5 volt VCC from the USB port. It should just feed to pin 21 through the transistor network.

If you get lost at all in Malc's schematic, just build Alessio & Andrea's and move the LED from pin 26 to 27, other than that they are identical in function.

As a side note, Alessio & Andrea's code is excellent as well! It's a little bit strange having two controllers, but their code gives you the ability to flash the eeprom with a small text file to change button/axis configuration through the USB. Super useful!
Jul 20, 2006, 06:16 PM
Heli Humbled Daily
I'm a little baffled now. My blade CX remote (negative pulse modulation) works fine with both M/M's USB board and A/A's project. 4 channel, excellent response.

My old JR remote (XF622) has not been working with the USB circuit, which I assumed was because I was using a stereo jack in the DSC port.

Today I picked up a mono 3.5mm jack and hooked it up to the circuit with the base of the minijack going to VCC and the tip going to signal in (port 21 of PIC) through the NPN transistor.... no response!

After some fiddlings, I switched the input from the JR so that tip (which I thought caried the signal!) is going to VCC and the base of the connector (which I thought was ground!) is going to PORT 21. I added a jumper wire from the USB 5 volt VDD to the same lead that connects to the tip of the remote, and now it works fine (the blade remote works, too, with the same setup!)

In a nutshell, I reversed the modulation from that suggested in the ciruit, and now the JR remote is working. I still need to use my voltmeter to make sure that I am not sending innapropriate voltages anywhere they shouldn't be.

I don't understand why the JR wouldn't work with the circuit as it stands. Essentially, I have to reverse the modulation on it to make it work? Anyone else had any similar difficulty with a JR remote?
Jul 21, 2006, 01:46 AM
Registered User
Thread OP
Can't shed any light on your delema, only that all the testing was done using a JR X3810 8ch TX through a mono 3.5mm plug with the tip wired as the signal input and the shaft gnd ! - on the scope trace the pulse train is postitive, ie they go from low to high.. maybe your other TX's have a negative going pulse train where the pulses go negative.. but my gut feeling is that it shouldn't matter
Jul 23, 2006, 09:49 PM
Heli Humbled Daily
Scrap it all, I was just missing a resistor. Built it to specs, and the thing works great. I also scrapped the zener diode idea, just use the transitor network.

Great project!
Jul 24, 2006, 04:29 AM
Registered User
Thread OP
Well the original design has been tried and tested, maybe its a case of you can't improve on perfection
Jul 28, 2006, 01:28 PM
Registered User

Error to compile rcjoy.asm

I made download of the archives rcjoy and tried to compile, but it appeared these errors. I do not know as to proceed! I am using MPLAB 7.21

Clean: Deleting intermediary and output files. Clean: Done. Executing: "D:\MPASM Suite\MPASM.EXE" /q /p18F2550 "rcjoy.asm" /l"D:\KRS\rcjoy.lst" /e"D:\KRS\rcjoy.err" /o"D:\KRS\rcjoy.o" /c- Error[105] D:\KRS\RCJOY.ASM 42 : Cannot open file (Include File "" not found) Warning[207] D:\KRS\RCJOY.ASM 44 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 44 : Illegal opcode (PLLDIV) Warning[207] D:\KRS\RCJOY.ASM 45 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 45 : Illegal opcode (FOSC) Warning[207] D:\KRS\RCJOY.ASM 46 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 46 : Illegal opcode (PWRT) Warning[207] D:\KRS\RCJOY.ASM 47 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 47 : Illegal opcode (WDT) Warning[207] D:\KRS\RCJOY.ASM 48 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 48 : Illegal opcode (MCLRE) Warning[207] D:\KRS\RCJOY.ASM 49 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 49 : Illegal opcode (STVREN) Warning[207] D:\KRS\RCJOY.ASM 50 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 50 : Illegal opcode (CP0) Warning[207] D:\KRS\RCJOY.ASM 51 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 51 : Illegal opcode (WRT0) Warning[207] D:\KRS\RCJOY.ASM 52 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 52 : Illegal opcode (WRTB) Warning[207] D:\KRS\RCJOY.ASM 53 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 53 : Illegal opcode (EBTR0) Warning[207] D:\KRS\RCJOY.ASM 54 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 54 : Illegal opcode (EBTRB) Warning[207] D:\KRS\RCJOY.ASM 56 : Found label after column 1. (CONFIG) Error[122] D:\KRS\RCJOY.ASM 56 : Illegal opcode (WRT3) Error[108] D:\KRS\RCJOY.ASM 152 : Illegal character (1) Error[151] D:\KRS\RCJOY.ASM 718 : Operand contains unresolvable labels or is too complex Error[113] D:\KRS\RCJOY.ASM 1233 : Symbol not previously defined (TMR_CENTER) Error[113] D:\KRS\RCJOY.ASM 1247 : Symbol not previously defined (TMR_CENTER) Error[113] D:\KRS\RCJOY.ASM 1405 : Symbol not previously defined (TMR_CENTER) Error[113] D:\KRS\RCJOY.ASM 1409 : Symbol not previously defined (TMR_CENTER) Error[113] D:\KRS\RCJOY.ASM 1566 : Symbol not previously defined (NBITS) Error[113] D:\KRS\RCJOY.ASM 1572 : Symbol not previously defined (TMR_RANGE) Error[113] D:\KRS\RCJOY.ASM 1574 : Symbol not previously defined (TMR_RANGE) Error[113] D:\KRS\RCJOY.ASM 1578 : Symbol not previously defined (TMR_CENTER) Error[113] D:\KRS\RCJOY.ASM 1580 : Symbol not previously defined (TMR_CENTER) Halting build on first failure as requested. BUILD FAILED: Thu Jul 27 21:44:21 2006

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