DIY Small Meter Movement?

General project help for Adafruit customers

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
smellzones
 
Posts: 3
Joined: Thu Sep 06, 2012 1:27 am

DIY Small Meter Movement?

Post by smellzones »

Hey Everyone,

I want to build a small display for an arduino project. Instead of sending out a voltage reading on an LCD screen or an LED setup, I want it to display as a meter movement. Like a galvanometer. I understand how PMMC's work, but for my project I don't need a huge meter like the ones you typically buy from radioshack. All I need is a tiny pin to move through a range of around 270 degrees with the diameter of 1.5 cm. Is there an easier way of building a meter movement without having to use a permenant magnet, hairspring coils, etc.? Something that would be relatively cheap and inexpensive?

Thank you so much!

User avatar
lyndon
 
Posts: 281
Joined: Tue Mar 29, 2011 5:28 pm

Re: DIY Small Meter Movement?

Post by lyndon »

You can probably use a pager/cellphone vibrator motor. Remove the offset weight and it's just a motor. Now add a spring to the shaft and you have a motor that will rotate according to how much current you feed it.

Mechanically tricky if you don't have the right tools, but it will work and is about the right size.

Or, if you have an extra $35 burning a hole in your pocket, use this tiny stepper motor: http://www.digikey.com/product-detail/e ... ND/2417057

User avatar
easternstargeek
 
Posts: 347
Joined: Mon Dec 13, 2010 1:39 pm

Re: DIY Small Meter Movement?

Post by easternstargeek »

If you can live with 180 degrees, use an inexpensive hobby servo. Since you are driving it with an Arduino, you have everything you need.
I have done this to make a large dial thermometer with excellent results.

It won't be as speedy as a d'Arsonval movement, but it should do the job for less than US$6.00:
http://www.adafruit.com/products/169

smellzones
 
Posts: 3
Joined: Thu Sep 06, 2012 1:27 am

Re: DIY Small Meter Movement?

Post by smellzones »

Thanks for the responses! I don't think they will work for my project though. Sorry I wasn't specific before, but I am building a midi controller, but I want all the displays for each knob to change when I adjust the value each knob controls on the computer. So for example, if I had my midi controller mapped to a software synthesizer, and then I changed presets for that synthesizer on the computer, my custom midi controller would know and it would change its display values accordingly.

Therefore, the option of using motors for every knob display would be too expensive, because I need several of them. Also, the motors will wear out with as much use as I will be giving them, I think. And I don't think the response will be as fast. I can comprise to just 180 degree range, that's ok, but I don't think motors will be good. I want to avoid using a numerical readout from an LCD. If I was able to have some sort of tiny graph bar light up at different values, that would be good too, but not sure if that's possible without using literally thousands of LEDs.

Thanks!

User avatar
adafruit_support_bill
 
Posts: 88096
Joined: Sat Feb 07, 2009 10:11 am

Re: DIY Small Meter Movement?

Post by adafruit_support_bill »

The led matrix with backpack is easy to drive. http://www.adafruit.com/products/871 But may be out of your price range.
We also have inexpensive LED bargraphs, http://www.adafruit.com/products/459

smellzones
 
Posts: 3
Joined: Thu Sep 06, 2012 1:27 am

Re: DIY Small Meter Movement?

Post by smellzones »

I think I will go with a bar graph LED display after all. I will maybe try and build my own with micro LEDs.

Thank you everyone for your input.

Locked
Please be positive and constructive with your questions and comments.

Return to “General Project help”