Topic: Army Truck Build

[JustBob]

Getting ready for spring shows ...

https://www.youtube.com/watch?v=7jrY4AIFiE8&feature=youtu.be

[IlikeImpala's]

How are you going to actuate the various facial features?  The linkage looks like you plan to use servos.

Also what kind of control are you planning to use?  Remote control? Arduino? Other?

[lowboy]

Looking good I like that

[just old]

that truck is really nice looking you did a great job on it

[Granpascrazzy]

THANX thats cool. sure beats lookin at pyle of parts

[obama]

Truck looks nice, good sheet metal work on the skull. Fun stuff.

[JustBob]

How are you going to actuate the various facial features?  The linkage looks like you plan to use servos.

Also what kind of control are you planning to use?  Remote control? Arduino? Other?

Servos would be nice but I'm gonna try choke cables with levers in the cab. 

[JustBob]

that truck is really nice looking you did a great job on it

Thanks ... lots of blood sweat and tears ... literally!

[JustBob]

How are you going to actuate the various facial features?  The linkage looks like you plan to use servos.

Also what kind of control are you planning to use?  Remote control? Arduino? Other?

Actually ... after some more research .. I think I'm going RC ... have any idea what size servos I would need?

[IlikeImpala's]

You can get cheap metal gear servos on ebay. I would buy a servo tester, then get 1 metal gear standard size servo and hook it up and see if it struggles when moving the various parts. Once you know how well that one servo works, then you can decide if you need bigger ones or not. Initially just buy one servo so you are not wasting money on servos you may never use. As there's no way that I could suggest a servo size when I have never seen your project. But a servo tester will allow you to drive a servo without having a RC radio, which is what you want for testing. Plus they are like $4 which is far cheaper than just buying a remote setup to begin with.

Additionally I can offer you another option. If you want to make the face move as a routine (making it a robot) I can help with that. Here's a simple servo program that you can load into any Arduino Uno micro controller that will allow you to define which servo moves at what time. The routine simply loops over and over. If using this code, all you need to do is copy and past this code into the Arduino IDE which is free software from the website arduino.cc then load it into the Uno micro controller and plug in the servos on the ports defined in the code. Poof then its robotically controlled. But you will have to adjust aspects of this code to make the face work how you want it to. But I can help with that should you choose to go this route.

On the code, it moves all 4 servos 180, then back to 0. Then it moves each servo one at a time to 180, then back to zero. Then loops. I wrote it for a Halloween project.

Here's a video showing how this code works -


EDIT - I don't know why the code is showing up as white on a white background. But its there, so just select it and you will be able to see it. - Weird!

Code: [Select]

#include <Servo.h>
 
Servo myservo2;  // create servo object to control a servo
Servo myservo4;  // a maximum of eight servo objects can be created, I'm controlling 4 in this code
Servo myservo7;
Servo myservo8;

int pos = 0;    // variable to store the servo position
int x;         // used for counting

void setup()
{
  myservo2.attach(2);  // attaches the servo on pin X of the Arduino Uno to the servo object
  myservo4.attach(4);
  myservo7.attach(7);
  myservo8.attach(8);
}
 
void loop()
{
  for(pos = 0; pos < 180; pos += 1)  // goes from 0 degrees to 180 degrees
  {                                  // in steps of 1 degree   
    myservo2.write(pos);              // tell servo to go to position in variable 'pos'
    myservo4.write(pos);
    myservo7.write(pos);
    myservo8.write(pos);
    delay(15);                       // waits 15ms for the servo to reach the position
  }
  delay(25);
  for(pos = 180; pos>=1; pos-=1)     // goes from 180 degrees to 0 degrees
  {                               
    myservo2.write(pos);              // tell servo to go to position in variable 'pos'
    myservo4.write(pos);
    myservo7.write(pos);
    myservo8.write(pos);
    delay(15);                       // waits 15ms for the servo to reach the position
  }
  delay(25);
    for(pos = 0; pos < 180; pos += 1)   //move one servo at a time
  {                                 
    myservo2.write(pos);             
    delay(15);                       
  }
    for(pos = 0; pos < 180; pos += 1)
  {                                 
    myservo4.write(pos);             
    delay(15);                       
  }
    for(pos = 0; pos < 180; pos += 1)
  {                                 
    myservo7.write(pos);             
    delay(15);                       
  }   
    for(pos = 0; pos < 180; pos += 1)
  {                                 
    myservo8.write(pos);             
    delay(15);                       
  }   
  delay(25);
  for(pos = 180; pos>=1; pos-=1)     //return one servo at a time
  {                               
    myservo2.write(pos);             
    delay(15);                   
  }
  for(pos = 180; pos>=1; pos-=1)     
  {                               
    myservo4.write(pos);             
    delay(15);                   
  }
  for(pos = 180; pos>=1; pos-=1)     
  {                               
    myservo7.write(pos);             
    delay(15);                   
  }
  for(pos = 180; pos>=1; pos-=1)     
  {                               
    myservo8.write(pos);             
    delay(15);                   
  }   
  delay(25);
    for(pos = 0; pos < 180; pos += 1)   //move one servo at a time
  {                                 
    myservo2.write(pos);             
    delay(15);                       
  }
   for(pos = 180; pos>=1; pos-=1)     //return one servo at a time
  {                               
    myservo2.write(pos);             
    delay(15);                   
  }
    for(pos = 0; pos < 180; pos += 1)
  {                                 
    myservo4.write(pos);             
    delay(15);                       
  }
   for(pos = 180; pos>=1; pos-=1)     
  {                               
    myservo4.write(pos);             
    delay(15);                   
  }   
    for(pos = 0; pos < 180; pos += 1)
  {                                 
    myservo7.write(pos);             
    delay(15);                       
  } 
   for(pos = 180; pos>=1; pos-=1)     
  {                               
    myservo7.write(pos);             
    delay(15);                   
  }   
    for(pos = 0; pos < 180; pos += 1)
  {                                 
    myservo8.write(pos);             
    delay(15);                       
  }   
   for(pos = 180; pos>=1; pos-=1)     
  {                               
    myservo8.write(pos);             
    delay(15);                   
  } 
   delay(25);
}


[JustBob]

That's some cool AI stuff right there. I am a computer programmer so I wasn't shocked .. well maybe shocked that the code is so simple. But I think for now ... I want the facial features to be dynamic and user controlled.

But let me ask this ... would the same transmitter and receiver work with different servos? Could I purchase those and say a 20kg servo and if that was not enough upgrade to a 30kg servo with the same transmitter and receiver?

I don't know squat about RC stuff as you can tell.

[IlikeImpala's]

Most regular servos use a standard analog PPM signal to operate. But some brands do vary in how they are driven. Digital, I2C, Serial, Zigbee, Wifi, RF, etc are used by different brands for different applications. Me, I would use regular analog servos like this one LINK as they are cheap and proven technology. This exact one should be good enough. A cheap radio like this one LINK should work. You really don't need fancy features, just enough channels to make it move. Shop around for the best price. So to answer your question, a regular RC radio will work with regular analog (PPM) servos. But not all servos will work with a regular RC radio. PPM = Pulse Position Modulation

Here's a link to a servo tester LINK which is a cool tool to have when messing with servos. Plus at $4 who cares if you only use it once or twice.

Me, I would go the Arduino route over using an RC radio. Because its nothing to add a flip switch to your dash to send 12v to the Arduino which makes the face move, then when driving shut it off. Arduino's and servos use nothing for power, so you should be able to leave it run for hours during a show without killing your car battery. Or just add a small battery to power it separate. But its your project so either way.
 
Oh and I'm also a programmer.     

[JustBob]

Most regular servos use a standard analog PPM signal to operate. But some brands do vary in how they are driven. Digital, I2C, Serial, Zigbee, Wifi, RF, etc are used by different brands for different applications. Me, I would use regular analog servos like this one LINK as they are cheap and proven technology. This exact one should be good enough. A cheap radio like this one LINK should work. You really don't need fancy features, just enough channels to make it move. Shop around for the best price. So to answer your question, a regular RC radio will work with regular analog (PPM) servos. But not all servos will work with a regular RC radio. PPM = Pulse Position Modulation

Here's a link to a servo tester LINK which is a cool tool to have when messing with servos. Plus at $4 who cares if you only use it once or twice.

On the code above. It moves all 4 servos 180, then back to 0. Then it moves each servo one at a time to 180, then back to zero. Then loops. I forgot to add that to my previous post. I wrote it for a Halloween project. Me, I would go the Arduino route over using an RC radio. Because its nothing to add a flip switch to your dash to send 12v to the Arduino which makes the face move, then when driving shut it off. Arduino's and servos use nothing for power, so you should be able to leave it run for hours during a show without killing your car battery. Or just add a small battery to power it separate. But its your project so either way.
 
Oh and I'm also a programmer.     

That's great info ... I see you love Ebay also ... I'm like a kid in a toy store on eBay! Sometimes, I sell some of my junk on there to pay for my toys.

[IlikeImpala's]

I moved some of my comments around to keep them on topic, and I added a video link to the code post showing how the Arduino works at driving some cheap-o small airplane servos. I made that as part of a Wolf Arm Halloween project. The servos make the fingers move on a severed wolf arm Halloween display.

Ebay is typically the cheapest place for most items. The competition with Chinese sellers drives the prices down.

[IlikeImpala's]

@Bob
You can get faster servos, but they cost a little bit more. But before you throw money at them consider the fact that you can make your face parts move faster by linkage advantage. So you might test with a regular servo, then try a different length arm for faster movement before buying faster servos.

[JustBob]

Got er done! The Dead Redneck Sheet Metal Skull is alive and well!

Now to clean it up and get to Hammond Square Mall next Saturday 25th for the Cars For Kids Car Show.

Thanks to Robin Coates at www.RobzArt.com for the COOL Dead Redneck Logos ... she is all things graphics!

[JustBob]

@Bob
You can get faster servos, but they cost a little bit more. But before you throw money at them consider the fact that you can make your face parts move faster by linkage advantage. So you might test with a regular servo, then try a different length arm for faster movement before buying faster servos.

Finally got my servos and tester and battery pack ... also got a 12v to 6v diode ... you think it would be safe to run it off the car battery with that diode?

By the way, I ordered the servos you recommended and they are strong and fast ... now I have a couple days to convert it from choke cables to RC .... gonna make things a LOT better ... thanks for that info!

[IlikeImpala's]

No you should power them with a step down power supply. Something like this LINK
Its an issue of filtering noise over simply dropping voltage. And actually I use this power supply more frequently than all others LINK But you have to solder this one together as its just a bag of parts and a bare PCB.


Also I watched your video, the completed face is pretty cool. Once you get the servos installed you might consider some LED lighting on the face/eyes. Ebay has really cheap cut to length water proof LED strips. I've used them everywhere on countless projects. They are totally worth the money spent.

[JustBob]

No you should power them with a step down power supply. Something like this LINK
Its an issue of filtering noise over simply dropping voltage. And actually I use this power supply more frequently than all others LINK But you have to solder this one together as its just a bag of parts and a bare PCB.


Also I watched your video, the completed face is pretty cool. Once you get the servos installed you might consider some LED lighting on the face/eyes. Ebay has really cheap cut to length water proof LED strips. I've used them everywhere on countless projects. They are totally worth the money spent.

Thanks for that ... gonna go with the eBay one.

[JustBob]

Got the electronics installed .... works great!

[IlikeImpala's]

....and he just looks so dam happy!   -lol


But seriously, I'm pretty picky on ratrods. Most of them I just don't relate to. This one is pretty amazing even without the animatronic skull head. Amazing job, sir.

[JustBob]

....and he just looks so dam happy!   -lol


But seriously, I'm pretty picky on ratrods. Most of them I just don't relate to. This one is pretty amazing even without the animatronic skull head. Amazing job, sir.

Yea I think he  likes it a lot ... except for reverse .... he gets wondering eyes and raised eye brows when I back up.