Webra Picco and 2.4 GHz conversion with original #1271 actuator.

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F2B
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Location: 20 m NE of Amsterdam

Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by F2B »

Tolle Sache!
Auch ich bedanke recht herzlich.
Da werden wir Mal sehen was daraus wird.
Es tauchen immer solche verloren geahnte Sachen auf innerhalb von unserem Vintageverein The First Aviators.
Max wird sich widmen an der Fertigstellung der 2,4 Version.
Daneben bin ich zur Verfügung für "Mitdenken" und sonstiges.
F2B or not to be....
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tiptipflyer
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Location: Germany

Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by tiptipflyer »

Nichts zu Danken, es freut mich, wenn ich ein wenig helfen kann.

Although it is much harder for me, I continue in english now, so that all others can also benefit.
I use 2S lipo for the webra actuator (around 8V) which is adequate for a small model with easy moving rudder (sewn hinges).
The actator is not very powerfull. When flying it in a Sharkface, I had problems to turn when the motor was under full power due to the prop-wash. So I had to reduce power for every turn. This is no problem in the Aeronaut Nova.

To convert the TX I made a PCB with everything on it but the RF module and the throttle pot. If you can etch a PCB here is the drawing:
WebraPicco.pdf
(1.32 MiB) Downloaded 162 times
The PCB fitts exactly into the Tx case in place of the original PCB.
Webra6.JPG
It uses an ATtiny 85 as a single chip with additional P5, a 10k poti with 4mm axis for rudder and another separate 10k pot for proportional throttle.
Features:
- Rudder servo reverse
- Inactivity buzzer
- Low voltage alert
- Throttle lock and alert on power-up.
- Provision for an extra switch for another channel or any special feature (GG on a standard servo for expl)
Works really well.

Cheers
Frank

Edit: I added a small picture of the finished and installed PCB that everybody can see how it looks like.
Last edited by tiptipflyer on 25 Dec 2020, 09:30, edited 1 time in total.
MaxZ
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Location: Boskoop, Netherlands

Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by MaxZ »

Thanks again Frank. Yes you are right, we should continue in English.

Cheers,
Max.
MaxZ
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Joined: 31 Jan 2019, 11:48
Location: Boskoop, Netherlands

Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by MaxZ »

Hi again Frank,

I have been studying your PCB layout, and most of it is clear. But I do not quite understand the two diodes, the one without identification, and rather large mounting holes, in between the battery + connection and the input to the voltage regulator.
And the other one, the BAT43, is clearly some sort of protection for the HF module, but is it the right way around? Would it be necessary for my Frsky DHT module?

Cheers,
Max.
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tiptipflyer
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Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by tiptipflyer »

The big diode is just a polarity protection diode. 1N4007 or similar. You can use a jumper wire if you never connect the battery the wrong way. (don´t ask why I always use them)
The BAT43 Schottky diode is an input protection for the module, which can be replaced by a jumper or 1k resistor for most modules. As far as I know only Corona modules require the diode. I use Orange modules and 35MHz modules, they require nothing, just a jumper.
The Attiny85 is a plain DIP8 chip only.
The transistor for the buzzer is a BC547 or 2N3904 or similar.

Frank
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Phil_G
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Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by Phil_G »

MaxZ wrote: 21 Dec 2020, 14:44... the BAT43, is clearly some sort of protection for the HF module, but is it the right way around?
It is the correct way around Max, the encoder pulls the PPM line 'low' and the modules internal 3v3 pullup provides the 'high'.
This was only necessary for Coronas and the early Frsky V8 modules. Frsky later (crudely) added a schottky in the PPM wire.
Its not necessary for a DHT, Orangerx, Flysky, etc.
Cheers
Phil
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diode.jpg
MaxZ
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Location: Boskoop, Netherlands

Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by MaxZ »

Thanks Phil
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tiptipflyer
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Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by tiptipflyer »

Phil_G wrote: 21 Dec 2020, 19:57 Frank I wonder if placing a couple of small neodymium magnets would help give the Webra actuator a bit more torque?
Not sure how it works, maybe near the coil or on the rotor?
Cheers
Phil
Thanks Phil for pointing this up, I will try it out at a later time.

For all the interested guys, I added a small picture to the previous post to make clear how the PCP will look like.

Frank
MaxZ
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Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by MaxZ »

Tidy installation Frank! Gives you a good impression of the space inside the Picco case.
Interesting text "TURBO SW" on the module connection..... :P

I have the digispark for the converter readily programmed, I am waiting for the MIC4427 ordered by a friend for me to solder it all on a piece of Vero board. Will be after Xmas.

I stripped down Phil's arduino sketch for rudder input only, as the Picco has no elevator function. However, I will use the original after all, and install an additional trimpot as a pseudo-elevator channel in the Tx to have the possibility to change the cycle time of the Picco actuator remotely if and when required. That will avoid having to remove the converter from the plane, reload the sketch with a revised cycle time and reinstall it again. The person I am doing this project for lives a fair distance away from me, and I don't think he has an arduino set up to do the above himself, so we need to send everything back and forth by mail...

Cheers,
Max.
MaxZ
Posts: 330
Joined: 31 Jan 2019, 11:48
Location: Boskoop, Netherlands

Re: Webra Picco and 2.4 GHz conversion with original #1271 actuator.

Post by MaxZ »

Right, I've got the recoder for the Picco ready and working, albeit with a dummy load of a single LED. The Arduino code is based on Phil's GG recoder, stripped of the elevator channel since the Picco is rudder only. I did not go for the original code with elevator input controlling the cycle time, but mounted a multi-turn pot on the PCB supplying input for one of the analog ports. The idea is that, once the optimal cycle time for the Picco has been established, it can be coded as a fixed number and the pot can go. At present, the pot will control 80 - 300 ms cycles. Here is a video:



One thing that I cannot explain: once I had powered the ATtiny the LED started blinking, before I connected the 9V battery to Vin of the MIC4427 driver :?:

Cheers,
Max.
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