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Feb 21, 2007, 02:17 PM
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FredericG's Avatar
Quote:
So, the only option that I see is the digital pot suggestion above.
Is there a need to use a true digital potentiometer; would a simple, cheap DAC not work?
A joystick interface measures the time to charge a cap over the pot in the joystick but I have the impression that in our transmitters the status of the pots of detected with ADC's?

Frederic
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Feb 21, 2007, 02:46 PM
Happy FPV flyer
Kilrah's Avatar
I had used a DAC with Futabas, that worked perfectly. However that might not be true for all. I think Graupner needs the acutal resistance. Now the problem is that they of course will all be using different pot values
Feb 22, 2007, 02:28 AM
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FredericG's Avatar
Quote:
Originally Posted by Kilrah
I had used a DAC with Futabas, that worked perfectly. However that might not be true for all. I think Graupner needs the acutal resistance. Now the problem is that they of course will all be using different pot values
That means such an interface would be less universally applicable than I thought.

I think I will follow this path, using a DAC. Any suggestions for an easily available DAC (serial interface, 2 channels?)

Frederic
Feb 22, 2007, 03:38 AM
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AnthonyRC's Avatar
Thread OP
Quote:
Originally Posted by FredericG
That means such an interface would be less universally applicable than I thought.

I think I will follow this path, using a DAC. Any suggestions for an easily available DAC (serial interface, 2 channels?)

Frederic
Personally I would go the Digital Potentiometer route, using the dallas/maxim parts which DS1803. This is available in 3 variants, with resistances of 10k, 50k, and 100k (I assume that these would cover most transmitters... can anyone confirm?)
It uses an i2c bus, easy to interface to a PIC, and contains 2 pots ,so pan/tilt solved with one device.
Samples of the part may be ordered from the dallas site, pricing is listed as just over $2 in large quantities, $3.18 for 1-24.

For a PIC, you could probably get away with one of the 8-pin parts, using its internal oscillator. This would decode the PPM, and during the idle period, write the values to the pot.

I could knock together some prototype boards in the basement if needed.

I believe that this would function with the TrackR1, and almost definitely the GyroControl also.
Feb 22, 2007, 04:29 AM
Happy FPV flyer
Kilrah's Avatar
As I said I guess there would be some trial needed for the value. It seems 5k is usual in transmitters, now if they really use the resistance it might screw if using 10k.
Feb 22, 2007, 04:57 AM
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AnthonyRC's Avatar
Thread OP
Neither Maxim nor Microchip have a 5k version, but it looks like analog does:
http://www.analog.com/en/prod/0,,761...5160%2C00.html

This is available in 5, 10, 50, 100k versions.
Feb 22, 2007, 05:21 AM
Registered User
FredericG's Avatar
I see, I thought a digital pot was expensive. I can also see the advantage of a digital pot.

Yes, I think HW/SW this would be a simple (but fun) project.

I am willing to work on this but the problem is that I won’t have time in the coming weeks/month. If you would make a prototype board, that would be nice. I suppose I could also just put a PIC and a digital pot on a breadboard for a POC.

Frederic
Mar 03, 2007, 07:35 PM
Resistance is Futile
camship's Avatar
Just a note about Futaba 8 Channel TX's of the UAH/UAP, UAFS/UAPS varieties.

Verified in all three manuals, 8UAFS/8UAPS, the 8UHPS and 8UAPS, (known as the Super "8"'s).

SNIP-

Trainer function operation modes:
"FUNC": When the trainer switch is ON, the channel set to this mode can be controlled by the student by using the mixing set at the instructor's transmitter. AHA! Very interesting and very important when using a trainer box, PC generated PPM or any non-programmable TX with the TrackR1 in a Trainer/Student configuration or with just the TrackR1 since you still have mixing and trim,(subtrim) functions available to you with any selected input channel.
"OFF": The channel set to this mode cannot be controlled by the student even when the trainer switch is ON. The set channel can be controlled by the instructor only.
"NORM": When the trainer switch is ON, the channel set to this mode can be controlled by the student. The set channel is controlled according to the contents set at the student's transmitter.


You may use your 8UA transmitter with any transmitter of the SKYSPORT, Super 7, or 1024Z series of transmitters. -SNIP

The Futaba "8"'s are perfectly happy with any plain vanilla garden variety 4+ channel source that puts out PPM on the right pins. But puzzle me this one Batman...the 1024Z mentioned above is a NINE channel TX...

Everything you ever wanted to know about Futaba Hobby equipment.

Camship
Mar 03, 2007, 09:38 PM
Fly FPV, sleep; repeat
twinturbostang's Avatar
Quote:
Originally Posted by camship
Trainer function operation modes:
"FUNC": When the trainer switch is ON, the channel set to this mode can be controlled by the student by using the mixing set at the instructor's transmitter. AHA! Very interesting and very important when using a trainer box, PC generated PPM or any non-programmable TX with the TrackR1 in a Trainer/Student configuration or with just the TrackR1 since you still have mixing and trim,(subtrim) functions available to you with any selected input channel.
"OFF": The channel set to this mode cannot be controlled by the student even when the trainer switch is ON. The set channel can be controlled by the instructor only.
"NORM": When the trainer switch is ON, the channel set to this mode can be controlled by the student. The set channel is controlled according to the contents set at the student's transmitter.
The 9C is the same as this.

Quote:
You may use your 8UA transmitter with any transmitter of the SKYSPORT, Super 7, or 1024Z series of transmitters. -SNIP

The Futaba "8"'s are perfectly happy with any plain vanilla garden variety 4+ channel source that puts out PPM on the right pins. But puzzle me this one Batman...the 1024Z mentioned above is a NINE channel TX...
Yeah, that's the 9Z. Still works though. I don't understand the problem. If the 9Z is the master, then it takes up to 8ch inputs (the 9th channel is not assignable on the trainer port) and replaces it's own values with those. If the 8UA is the master, then it will also accept up to 8ch inputs (AFAIK) and replace it's own values with those. Even if you use a 6 or 7 channel Tx as the master, it should still work. It's just that it will (I think) clip off the extra channel inputs and only accept up to the maximum allowed of the master Tx. Although I think I have heard of workarounds for the Multiplex and other Tx's that will append the added channels found on the trainer port. Not 100% of that though.
Mar 04, 2007, 10:00 AM
Resistance is Futile
camship's Avatar
twinturbostang

Actually I wan't looking at it from a problem standpoint, I was wondering if there might be an association here similar to the one you mentioned about the Multiplex and other Tx's that might be of beneficial use in some way.

For instance. I use the frequency module for the 75 MHz PCM capable pistol grip 2,3 and 4 channel transmitters in my F8's for switching to ground control applications with no problem whatsoever and have a full compliment of channels available with proper receiver.

So I was wondering if anyone had any experience with similar applications that got unexpected but positive results? Essentially if you might possibly be able to append additional channels onto the trainer port and have the corresponding number of useable channels with a matching receiver ala perhaps 9+ channels...?

The advantage is that with applications like the TracR1 a simple receiver upgrade and the proper signal being sent to the trainer port equates to no loss of existing control channels from the 8 channel limitations of the TX.

Or in the same fashion use a 6 channel TX with an 8 channel receiver? Yes? Maybe?


Camship
Last edited by camship; Mar 04, 2007 at 10:09 AM.
Mar 05, 2007, 03:54 AM
Happy FPV flyer
Kilrah's Avatar
Quote:
Originally Posted by camship
Just a note about Futaba 8 Channel
The Futaba "8"'s are perfectly happy with any plain vanilla garden variety 4+ channel source that puts out PPM on the right pins. But puzzle me this one Batman...the 1024Z mentioned above is a NINE channel TX...
Careful, the FUNC setting only exists on the 8 "Super", not in the conventional one.
Not a problem for headtracking though, can use the ON position too if the headtracker has the necessary adjustments built-in.
I have the 1024Z or 9Z, it doesn't have the FUNC setting and I'm doing fine with it. And yes it's a 9-ch TX, as is the 9C. But, both can only use the 9th channel in PCM mode, and it's an on-off one, with no setting possible but reverse (takes just 1 bit in the PCM frame).

Regarding adding channels, I recall something about the skysport 4 where you could hack an extra pot somewhere and get an extra channel. Haven't seen anything for the more advanced ones.
Mar 05, 2007, 04:34 AM
Registered User
AnthonyRC's Avatar
Thread OP
Quote:
Originally Posted by camship
twinturbostang

Actually I wan't looking at it from a problem standpoint, I was wondering if there might be an association here similar to the one you mentioned about the Multiplex and other Tx's that might be of beneficial use in some way.

For instance. I use the frequency module for the 75 MHz PCM capable pistol grip 2,3 and 4 channel transmitters in my F8's for switching to ground control applications with no problem whatsoever and have a full compliment of channels available with proper receiver.

So I was wondering if anyone had any experience with similar applications that got unexpected but positive results? Essentially if you might possibly be able to append additional channels onto the trainer port and have the corresponding number of useable channels with a matching receiver ala perhaps 9+ channels...?

The advantage is that with applications like the TracR1 a simple receiver upgrade and the proper signal being sent to the trainer port equates to no loss of existing control channels from the 8 channel limitations of the TX.

Or in the same fashion use a 6 channel TX with an 8 channel receiver? Yes? Maybe?


Camship
It is certainly possible to append channels via the trainer port on most radios, especially the low-end units.
I have a 4-channel low-end Futaba, and a Hitec Laser 4, on the bench, and both appear to work nicely with the TrackR1 in 'PPM Reprocess' mode.
This mode takes the PPM output from the Tx, and reproduces the first 4 channels with pan/tilt tacked onto the end. This signal then gets shoved back into the PPM input of the Tx.
One minor issue with this is the use of receivers which use DSP to prove 'Transmitter Signal Recognition'. When you enable the trainer port, the number of channels transmitted changes, and the receiver blocks the signal (Berg 7P is one example of a Rx that does this).
With receivers which aren't 'smart' this isn't a problem though.
Mar 05, 2007, 08:38 AM
Registered User
AndrésMtnez's Avatar
I know of someone here in Spain who is developing a HT (he initially doesn´t think about market it) and have succesfully used a FF6 tx using 2 new channels for the HT and still have 6 free channels for the rc control.

But don´t ask me more, I´m too stupid to understand more of the process
Mar 06, 2007, 08:56 AM
Helnet @--X
Helnet's Avatar
I own a 8103 JR radio and would like to buy another 6 channels radio to connect the Head trackr1.

Which Futaba 6 channels radio do you suggest to connect with the head Trackr1 ?

What do you think about the new Futaba model 6EX 2.4ghz ?

Thank you
Helnet
Last edited by Helnet; Mar 06, 2007 at 09:11 AM.
Mar 06, 2007, 10:13 AM
Mr.Pibb's Avatar
Quote:
Originally Posted by Helnet
I own a 8103 JR radio and would like to buy another 6 channels radio to connect the Head trackr1.

Which Futaba 6 channels radio do you suggest to connect with the head Trackr1 ?

What do you think about the new Futaba model 6EX 2.4ghz ?

Thank you
Helnet
If you switch to a 2.4GHz radio, I recommend going to 900MHz for video. You are flirting with disaster running a high powered video TX running at close to the same frequency as you radio system. I started to set up a 2.4GHz video system to put on my planes. My radio is a Spektrum DX6. Although for ground tests I didn't notice any ill effects on my plane's controls, I was getting interference in the video when my DX6 transmitter was on.

I just purchased a 500mW 900MHz system from rangevideo. I haven't flown it yet but so far the ground tests have been excellent. Much less in the way of multipath issues, and no interference from wifi, cordless phones, etc...

I do think that going 2.4GHz for the radio is a good idea, I just wish the trackr1 worked with the trainer port on the Spektrum systems. Blame Horizon/JR for that one, though.


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