DIY actuator RCM&E GG-Pelle

[Tobe]

The attached file includes all necessary parts to print your own DIY. Printing details on the instruction sheet

Hardware:
Spring general dimensions:
Pull to Pull Length (mm) 19 - 20 mm
Outside Diameter (mm) 3.2 - 4.0 mm
Wire Diameter (mm) 0.36 - 0.4

0,4X3X20 mm ( Lesjofors 3242: ES 0,4X3X20 is the one I use)

Motor:
Gear motor N20-6V 400RPM

Steel dowel pins:
1,5 mm x 20 mm 2 pcs
1,5 mm x 24 mm 1 pc

and a couple of "Starlock / Starwasher " for 1,5 mm but could be replaced with properly CA retainers as shown
!,5 mm can be replaced with 1/16"

[Tobe]

Here are two versions of the Arduino sketch for the DIY Re-Coder. Either an Arduino Pro Mini 328P 16 MHz 5V or an Arduino Nano in junction with a Pololu DRV8838 Motor Drive Bridge setup

At the beginning of each sketch there is a note with some additional notes and credits please read carefully.

V1.0a is a straight forward Re-Coder which needs its adjustment, if needed, done from the transmitter

V1.1a have added a “calibrate the Rx to the recoder” feature so you won’t need to adjust anything on the transmitter if you prefer.

· To calibrate the recoder, ensure the aileron (used for rudder) and elevator joysticks are in the centre and fit the jumper link on the calibrate header pins A0 and A1

· Wait for the LED to illuminate, then move the aileron and elevator joystick(s) to their limits in all directions.

· Remove the link and calibration is complete and the LED should go off

· You can check the calibration by moving the elevator joystick, the on-board LED should illuminate at it's limits and at neutral. To check the aileron stick, move the elevator from neutral (so the LED goes off) and move the aileron joystick to it's limits, again the LED should illuminate

· To reset the calibration to default (1mS-2mS) fit the calibrate link with the power off and power up. The LED will briefly flash to confirm the reset.

· After calibration or resetting the calibration, you must cycle the power off/on before you can calibrate again.

Last but not least, this Re-Coder is a work of love with sweat and tears from members to this forum:

Phil_G, Martin and Mike K where everything started by Shaun's pestering of Phil_G because he wanted to fly a plane donated to him with the original Rand LR2 with a modern radio.

More info and details will be out there in the December issue of RCM&E.

[Tobe]

For the one that want an extra challenge here comes a Recoder based on the DigiSpark ATTiny85. This Recoder fits inside the DIY. I would recommend to load the sketch by ICSP and not the USB port to get a swifter start up in accordance with Phil previous instructions viewtopic.php?f=41&t=60

[Tobe]

Here comes some guidelines for whom of you would like to go for the Dual Pack option.
To remember is that you will need 2 sets of actuators and Recoders.
Each actuator is completely separate from the other, basically each actuator is an independent "Servo" w/o interaction between them i.e. no elevator on rudder input and the direction of controls can be reversed from the transmitter which was a No-No for elevator on the regular actuator/set up.

[waynew17]

I just wanted to thank Tobe and Phil G for all their hard work on these GG projects and Phil's quick responses when I had an issue. I finally have a working GG. See attached photo. Thanks again guys!

[Tobe]

Good to hear of your progress and hope it will bring you as much pleasure I had designing it.
So it’s time to hit the stack of balsa wood and shape large pieces into small pieces that creates a model.

Cheers
Tobe

[waynew17]

I've had good success programming the digispark using the on-board usb. I have unfortunately been unsuccessful trying to program the digispark using my usbasp programmer. I keep getting the following error "Compilation error: 'GIMSK' was not declared in this scope". Any thoughts? See below:

C:\Users\wlw77\Documents\PDF Documents\Aviation - Model\Vintage RC Radio Upgrade\DigiSpark ATTiny85 recoder\DigiSpark ATTiny-DRV8838 Files\Digispark based recoder V3\Recoder_v3_DigiSpark\Recoder_v3_DigiSpark.ino: In function 'void setup()':
C:\Users\wlw77\Documents\PDF Documents\Aviation - Model\Vintage RC Radio Upgrade\DigiSpark ATTiny85 recoder\DigiSpark ATTiny-DRV8838 Files\Digispark based recoder V3\Recoder_v3_DigiSpark\Recoder_v3_DigiSpark.ino:71:3: error: 'GIMSK' was not declared in this scope
GIMSK = (1 << PCIE); // Enable Pin Change Interrupts
^~~~~
C:\Users\wlw77\Documents\PDF Documents\Aviation - Model\Vintage RC Radio Upgrade\DigiSpark ATTiny85 recoder\DigiSpark ATTiny-DRV8838 Files\Digispark based recoder V3\Recoder_v3_DigiSpark\Recoder_v3_DigiSpark.ino:71:3: note: suggested alternative: 'EIMSK'
GIMSK = (1 << PCIE); // Enable Pin Change Interrupts
^~~~~
EIMSK
C:\Users\wlw77\Documents\PDF Documents\Aviation - Model\Vintage RC Radio Upgrade\DigiSpark ATTiny85 recoder\DigiSpark ATTiny-DRV8838 Files\Digispark based recoder V3\Recoder_v3_DigiSpark\Recoder_v3_DigiSpark.ino:71:17: error: 'PCIE' was not declared in this scope
GIMSK = (1 << PCIE); // Enable Pin Change Interrupts
^~~~
C:\Users\wlw77\Documents\PDF Documents\Aviation - Model\Vintage RC Radio Upgrade\DigiSpark ATTiny85 recoder\DigiSpark ATTiny-DRV8838 Files\Digispark based recoder V3\Recoder_v3_DigiSpark\Recoder_v3_DigiSpark.ino:71:17: note: suggested alternative: 'ACIE'
GIMSK = (1 << PCIE); // Enable Pin Change Interrupts
^~~~
ACIE
C:\Users\wlw77\Documents\PDF Documents\Aviation - Model\Vintage RC Radio Upgrade\DigiSpark ATTiny85 recoder\DigiSpark ATTiny-DRV8838 Files\Digispark based recoder V3\Recoder_v3_DigiSpark\Recoder_v3_DigiSpark.ino:72:3: error: 'PCMSK' was not declared in this scope
PCMSK = (1 << rudder_ch) | (1 << elev_ch); // Enable interrupts for rx channel inputs
^~~~~
C:\Users\wlw77\Documents\PDF Documents\Aviation - Model\Vintage RC Radio Upgrade\DigiSpark ATTiny85 recoder\DigiSpark ATTiny-DRV8838 Files\Digispark based recoder V3\Recoder_v3_DigiSpark\Recoder_v3_DigiSpark.ino:72:3: note: suggested alternative: 'PCMSK1'
PCMSK = (1 << rudder_ch) | (1 << elev_ch); // Enable interrupts for rx channel inputs
^~~~~
PCMSK1

exit status 1

Compilation error: 'GIMSK' was not declared in this scope

[Tobe]

Good morning,
you have to treat it as an ATtiny85 and not as a Digispark with ATtiny Microcontrollers or as described here:
viewtopic.php?f=41&t=60&p=98&hilit=attiny#p98
You have to to start with burning the bootloader again however.

[Phil_G]

I've had good success programming the digispark using the on-board usb. I have unfortunately been unsuccessful trying to program the digispark using my usbasp programmer. I keep getting the following error "Compilation error: 'GIMSK' was not declared in this scope". Any thoughts?

Those are all compiler errors Wayne, not related at all to your usbasp or any programming method.
It looks like you have the wrong chip type selected, ie the compiler is targeting a type of MCU that does not have the GIMSK register
Or your ATTiny support is missing, I use (IIRC) the ATTinycore by Spence Konde.
Once you get a clean compile, then you're ready to upload using the usbasp, choose "Upload using programmer" not "upload" nor the arrow
(having specified usbasp as the programmer and set your ATTiny85 clock options appropriately)

You have to to start with burning the bootloader again however.

Theres no explicit "set clock options" so what Tobe means is that you have to set them in the IDE menu then use "burn bootloader", not that we want the bootloader, but as a by-product burning the bootloader also sets the clock fuses etc as we specified them in the IDE menus
Cheers
Phil

[waynew17]

Well, I loaded the ATTiny support files as they were missing. Now I get the following errors when attempting to install bootloader...

avrdude: set SCK frequency to 187500 Hz
avrdude: warning: cannot set sck period. please check for usbasp firmware update.
avrdude: error: program enable: target doesn't answer. 1
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override
this check.

Failed chip erase: uploading error: exit status 1

Sigh...