How-To Tuesday: Arduino 101 potentiometers and servos

Arduino Robotics Technology

Marc de Vinck

February 22nd, 2009 30

This is the 3rd installment of my Aduino How-To Tuesdays. This week I am going to cover using another basic part, the potentiometer. I will also cover connecting a servo to the Arduino. Servos can be hard to control, but not with the Arduino! That’s just another reason why I love this little micro-controller.

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30 thoughts on “How-To Tuesday: Arduino 101 potentiometers and servos”

Ville Kukko-Liedes says:

February 24th, 2009 at 8:57 am

I love how-to tuesdays and was happily surprised when I saw the topic on todays video. I myself am really into using servos in my projects altough I’ve always made my servo controllers myself. It’s awfully alot cheaper to make one out of a 555 timer and a few components. Costs like two bucks and fits on your thumb nail.

Anyway, I’m sure that Arduino offers alot more when it comes to using servos or anything but in tight space or low budjet I’d prefer just to making one of those 555 controllers.

I’ve always considered using codes and programmers as “cheating” when it comes to electronics and prefered analog systems. But who knows, maybe I should give Arduino a try. Sure looks like it can be alot of fun.

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1. Marc de Vinck says:
  
  February 25th, 2009 at 6:19 am
  
  @Ville Kukko-Liedes
  
  You are right, using a 555 is more efficient in the long run. However, using an Arduino is much more efficient in prototyping. I can get 2 servos up and running in under 2 minutes!
  
  Also, a lot of people do not have the knowledge to use servos with a 555. The Arduino opens up the world of electronics to many people. Later they can start hacking around with components.
  
  Finally, what are you making? Send me link so I can check it out. Do you have schematics that you would like to share with our readers?
  
  Thanks for commenting.
  
  Reply
Greg London says:

February 24th, 2009 at 11:11 am

Has anyone made a USB device or host with an Arduino? I know it has the USB port connector, but I haven’t seen any projects that actually use it for something.

I mean, if I wanted to make a super game controller that replaced my keyboard and joysticks with an Arduino controller, and plugged into my USB ports to act as keyboard and joystick, can I do that? Anyone actually prove it?

Can I do USB host somehow? Or at least USB-on-the-go?

All the microcontroller programmers I’ve seen use serial. The Arduino is one of the few that appears to use USB, but I can’t tell if you can actually use it as a USB device in a project, or if the USB is only for burning the prom.

I wrote a little perl script that uses the mouse to act like a morse-code key for training you morse code, but software can only do the dots adn dashes so fast, and it isn’t a real morse-code key. I was thinking of making a trainer that would use hardware to time the keystrokes, adn then send the timing information to the computer. Right now, it sends raw keystrokes to the ocmputer and software tries to time the dots and dashes.

http://www.cpan.org/authors/id/G/GS/GSLONDON/morse.pl

An Arduino acting as the hardware timer would allow the software to only worry about high level functions. But I need to convert the data to USB data, meaning I need to have the Arduino act like a USB mouse and/or keyboard.

Anyone see any projects that actually use the USB for something?

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1. Marc de Vinck says:
  
  February 25th, 2009 at 6:29 am
  
  @Greg,
  
  Check out this thread, it may help.
  
  http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1213375969
  
  Reply
Jhon Adams says:

February 24th, 2009 at 12:16 pm

Can you make a game controller that would replace my keyboard & joystick, with the Arduino controller, and plug it into my USB ports to act as A keyboard & joystick, will that work?

Reply
Go_USA says:

February 24th, 2009 at 2:17 pm

After the last series of How-To Tuesdays I was looking into getting started with Arduino boards until I read this:

“Note [from massimo]:We stress the fact that all the boards are made in italy because in this globalised world, were getting the lowest possible price for products sometimes translates into poor pay and working conditions for the people who make them, at least you know that who made your board was reasonably paid and worked in a safe environment. (this obviously applies only to the boards marked “made in italy”, other boards are now made in the USA)”

As an American I resent the implication and now refuse to support the product and project in any way. The comment is uncalled for. Read the comment for yourself here: http://arduino.cc/en/Main/Buy

Reply
1. Marc de Vinck says:
  
  February 24th, 2009 at 3:20 pm
  
  @Go_USA
  
  I think you may be taking this comment as anti-American. I don’t think it is, here’s why:
  
  Massimo is pointing out that many electronics are manufactured in countries where the workers are treated unfairly and work in deplorable conditions. The Arduino’s that are manufactured by the “Arduino team” are manufactured in Italy where workers have rights, the conditions are safe and the works are compensated fairly.
  
  The foot note about American made boards is to state that he (Massimo) can not attest to the manufacturing process of “third party” boards. This is not a dig on the US. Most of the Arduino clones are made in the USA, however I am starting to see boards from other countries too.
  
  Maybe it should be stated “other countries” instead of “USA”.
  
  We have a nice relationship with Massimo here at MAKE. I will ask him for his opinion too. Thanks for the input.
  
  Reply
Osc says:

February 24th, 2009 at 2:27 pm

Nice article. Also helpful to give some more info on servos: types, parameters that are compatible w/ arduino, and some resources for purchase, etc.

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Shaun says:

February 24th, 2009 at 8:58 pm

@Go_USA

The most cost-effective way to produce PCBs today, even for runs as small as 100, is to email your gerber files to China and wait for the post. You can then drop the components into the board in the USA, and call them “made” in the USA.

I believe all Massimo is saying, is that he’s chosen to buck that trend and produce them locally – taking the price hit, but allowing him to stand by his work, his team, and his product. I’m positive there’s plenty of Americans that wish that more companies could say the same!

The footnote simply stands because Arduino is an “open” product, allowing anyone to take the plans and replicate the product. Obviously Massimo can only stand by his own work, not that of others, as Marc said.

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Massimo Banzi says:

February 24th, 2009 at 11:33 pm

Sono italiano, non parlo inglese cosi bene come vorrei anche se lo uso tutti i giorni. La frase in questione si riferisce al fatto che ora le schede sono fabbricate in mezzo mondo e io posso mettere la mano sul fuoco solo per quelle fatte in Italia.

Imagine if the whole Arduino website was written like this ;) You would have a hard time reading but I would be 100% sure I don’t make mistakes :)

Apart from the jokes… English is not my main language even if I use it every day… I’m bound to make mistakes while I try make to communicate to as many people as possible by using English.

I would like to thank Mark and Shaun for explaining what my comment really is all about… They made a bery good job.

from now on the phrase will be “(this obviously applies only to the boards marked “made in italy”, we can not attest to the manufacturing process of “third party” boards). ”

Americans chill out… :)

Reply
1. Marc de Vinck says:
  
  February 25th, 2009 at 5:13 am
  
  @Massimo
  
  Thanks for commenting!
  
  Reply
wy says:

February 25th, 2009 at 1:51 am

Yesh! Go Massimo!!
Arduino!!
Very sweet tutorial by the way.

ciao

abbia un giorno piacevole
(babelfish)

Reply
dcwilson303 says:

February 25th, 2009 at 9:26 am

I was waiting for a video like this to inspire me. I bout the Arduno, a model kit and some servo’s but never sat down and started playing with it. This will not be the case anymore. THANK YOU!

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Ville Kukko-Liedes says:

February 25th, 2009 at 11:59 am

@Marc de Vinck

Hi! I make simple analog robotics. I don’t have any specific schematic or details on any of my projects but I drew you a schematic for the controller unit itself.

Schematic: http://i654.photobucket.com/albums/uu262/antipico/Servo555.png
Built: http://i654.photobucket.com/albums/uu262/antipico/IMG_2069.jpg?t=1235590998
Set up for testing: http://i654.photobucket.com/albums/uu262/antipico/IMG_2070.jpg?t=1235591014

Pin 5 is fed with 0-5V to control the servo. Servo should be centered with 2.5V. If not, it can be trimmed with the 2.2K variable resistor. (Can also be replaced with 1.5K resistor if trimming not needed) Pin 3 is the output for servo.

I shot a short film about testing this set up with two LDR-resistors.
http://www.youtube.com/watch?v=5Ke8gwnYDng
I’ve used this method on self-balancing robots, turning solar panels to face sun etc.

I’d appreciate if you could get this schematic published somewhere because there aren’t many solutions like this found on the net. I created this because I wasn’t happy with any other schematic available.
If you have any questions be welcome to contact me by e-mail at:
villekl(a)gmail.com

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Go_USA says:

February 25th, 2009 at 12:55 pm

@Massimo Banzi

If it was just a translational error which I now believe it to have been I must offer my apologies. The way the paragraph read originally struck a nerve as needlessly offensive, if you had meant it as written.

Thanks for clarifying and making a change so there could be no confusion in the future. Best of luck with the project and God bless!

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