Help With $50 Robot - Microcontroller/Servo Related

[yUNeeC]

Hi all,

I've started on the $50 project in order to increase my familiarity with electronics...however, I'm having some difficulties. I've searched high and low, but was unable to find an answer to my questions - so here I am.

Well, I got my servos in a couple of days ago and am finally ready to modify them. I read that the best way to do this is to use my microcontroller to change the servo's positions to zero. Well, I'm extremely confused. I just don't see how to make this connection (between the servos and the chip). Is the servo modification supposed to be done after the entire circuit is laid out, or can I do it now as step one? (I'm doing some semi-complex engineering on the chassis and would prefer having the servos finished and mounted first.)

My second concern is wandering if I got the correct equipment. I've seen the pictures of the microcontroller used in the tutorial, and it is a rectangle and a good deal longer than mine. I have a tiny square [it says Atmel mega8 16muo7171 korea-a 627389 on it]

Third, how do I go about programming the chip? I have the more expensive AVRISP2 programmer and can hook it up to my CPU...I just see nothing to connect my chip to it with.

I realize these questions are probably insanely stupid. Thanks for any help guys.

[SmAsH]

questions one and three must be done after you build the circuit.
for question three make sure you take note of admins comment about the different programming headers and change the pins so you only have 6.
question two... can you take a picture?

[Finnik]

About your second question...

The ATmega8 used in the 50 dollar robot tutorial is in a PDIP package, made to fit into a DIP socket. You have probably bought a surface-mount version of the ATmega8. The easiest solution would probably to find the ATmega8 in PDIP package somewhere.

However, if you are not afraid of soldering those tiny pins, you could also find an adapter PCB (like the ones on this page) to be able to fit it to your perf board. Look if there is a metal pad in on the bottom of the chip, if there is look for a MLF to DIP adapter, if there is not, look for a TQFP to DIP adapter. Of course you need to make sure it's for the right size. There are a number of tutorials on surface-mount soldering on the web, so just find one of them to see how to do it.

I hope this helps and good luck with building the robot!

[kpmcgurk]

question #1: please view my tutural on modifying servos without a microcontroller at www.firstairsoft.com/servo_mod
It will explain everything you will need to do.

question #2: You seem to have ordered the wrong microcontroller there are many fixes, your best bet would be just to buy the right one, they are only 4 bucks.

question 3: view this http://www.societyofrobots.com/robotforum/index.php?topic=1045.0

[yUNeeC]

Thanks for all the help guys. I think I'll just go with buying the correct microcontroller... this is my first project dealing with electronics and I'd be much more comfortable if I could just follow the template.

I was wandering if someone could help me find the correct microcontroller on mouser.com? I think this is it:

http://www.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMtkfMPOFRTOl6Pv4rHyfJei

Is this correct?

[kpmcgurk]

No that is not correct, here is the right one!!
http://www.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMvu0Nwh4cA1wQ0oVvyFXQLE2Vd4TR445XY%3d
Good luck with your first electronics project!!

NOTE* you will have many problems and many errors whether programing or electrical/mechanical, please do not be discouraged, do your best to work through the problems, It may be hard, and it will make you frustrated. Just take a break, and come back to the next day, and chances are you will figure out the problem right away!!!

[Webbot]

Given that it seems to be your first project then try following this http://www.societyofrobots.com/member_tutorials/node/193 during the electronics construction.

Not pushing my own tutorials but its much easier to sort out any problems as you go rather than at the end !

As others have said: this hobby may drive you nuts but when your monster twitches into life then its very rewarding. So be patient, ask for help when needed, and don't forget to post a video

[yUNeeC]

No that is not correct, here is the right one!!
http://www.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMvu0Nwh4cA1wQ0oVvyFXQLE2Vd4TR445XY%3d
Good luck with your first electronics project!!

NOTE* you will have many problems and many errors whether programing or electrical/mechanical, please do not be discouraged, do your best to work through the problems, It may be hard, and it will make you frustrated. Just take a break, and come back to the next day, and chances are you will figure out the problem right away!!!

Man I'm glad I asked!! Thanks a ton.

This stuff is pretty intense, but it's hard to discourage me. I'm a physics/math major (I'm used to discouraging amounts of work!) wanting to go into medical physics. Since medical physics requires an extensive background in electronics, I figure becoming proficient at robotics will be a major transcript booster for grad school. I've done a good deal of reading, and have decided to make this my first project so I can have some guidance before I turn myself loose. The most discouraging thing is waiting for things to get in...I want to finish this up, read up on what confused me, and then get creative.

[yUNeeC]

Given that it seems to be your first project then try following this http://www.societyofrobots.com/member_tutorials/node/193 during the electronics construction.

Not pushing my own tutorials but its much easier to sort out any problems as you go rather than at the end !

As others have said: this hobby may drive you nuts but when your monster twitches into life then its very rewarding. So be patient, ask for help when needed, and don't forget to post a video

I'm reading your tutorial right now. Thanks. Good thing to read before I start putting things together!