Starting up, need advice on parts.

[eiritsu]

Hi everyone, I found the resources very useful for me whose just starting in playing around in building mechatronic stuff.
I have something that I wish to build and need some advice.

This is what I am building:
I am making a mechatronic face and i will like to build an independent set of blinking eyes for the face.
I have read some of the resources and I'm thinking of using the timer on a micro controller to send signals to a servo which will cause eyelids to close and reopen at fix intervals.

How far is my progress now:
I have found a servo I intend to use on ebay and a programmer that connects to a usb port.
There seem to be a huge selection of micro controllers on ebay, but I am not sure which to pick.
The programmer supports quite a big range of micro controllers as well.
I will like to know what is the current software I can use to program the micro controller?

Right now, I'm kind of stuck and not sure what else I need.
Can I get some advice on what sort of circuit I need to build in order to be able to program the micro controller?
Or is there a board which I can just buy and what is it called?
I need it to be small to fit in the robot face which I will hook up to a couple of NiMH batteries.

I imagine an standalone circuit to control 2 servos should be simple enough, but I haven't done anything like this before, so any advice will be much appreciated.

[newInRobotics]

Hello.

I have read some of the resources and I'm thinking of using the timer on a micro controller to send signals to a servo which will cause eyelids to close and reopen at fix intervals.

It would work.

There seem to be a huge selection of micro controllers on ebay, but I am not sure which to pick.

It will be easier for You to use ATmega8 microcontroller as its use is already explained in detail in $50 Robot Tutorial, hence all You have to do is make identical board as in tutorial and alter the code a bit, but that's cheaper than making and fixing mistakes in Your circuit.

I will like to know what is the current software I can use to program the micro controller?

There are quite a few like AVRDUDE and AVR Studio. I think AVR Studio is the way to go as it is official IDE from Atmel Corp. Use WebbotLib as it is widely supported by users of this forum, hence getting help will be easier.

Can I get some advice on what sort of circuit I need to build in order to be able to program the micro controller?

As mentioned before - same circuit as for $50 Robot will do nicely.

Or is there a board which I can just buy and what is it called?

Axon or Axon II offers much more than You need, You'll be able to use it in Your projects in the future and it's supported by this forum as Axons creator is Admin (admin of this forum). Although this board is expensive, so if money is an issue - go for building board yourself.
As mentioned before - same circuit as for $50 Robot will do nicely.

I imagine an standalone circuit to control 2 servos should be simple enough, but I haven't done anything like this before, so any advice will be much appreciated.

First build MCU (board than makes microcontroller work) and program it to make Your servos work in a way You want. Later step will be to put those servos were You need them to be, but don't think about it now.

[eiritsu]

Good gracious,

That was a very good reply with lotsa of help that hit the spot.

I really like the care and aid given to a beginner so far.

Thank you, I think I have an idea where to start.

I'll get started and come back again to look for answers if I get stuck.

Thumbs up!

[Soeren]

Hi,

I am making a mechatronic face and i will like to build an independent set of blinking eyes for the face.
[...] I'm thinking of using the timer on a micro controller to send signals to a servo which will cause eyelids to close and reopen at fix intervals.

Rather than servos, take a look at SMA wire (memory wire/shape metal wire/muscle wire) for the job - it's silent and takes up much less space than a servo.
Eyelids that goes *weee-weee* at each blink don't appear realistic.

Another very good way to do it is to use small neodymium magnets on the eyelids and move them with an electromagnet (just a couple of coils of ine wire, perhaps with an iron core.

The eyelids should be hinged, self supported and fairly balanced (perhaps with a weak spring return), whichever method you use.


Further, a semi-random interval between each actuation (blinks) will appear more natural - we read a precise periodic happening subconsciously and will interpret it as an artificial (i.e. non-natural/non-biological) action.