aminnich Posted August 23, 2014 Posted August 23, 2014 Hey guys, I have been trying to build a mechanism to create the servo motion, but I cant use a servo. It cant return to center, it needs to stay in place. I hope that is not confusing. I tried gearing down a m motor and XL motor very slow, but they but have a recoil and don't stay in one place. It is really hard to explain. If anyone has any suggests, please comment. Thanks! Quote
JopieK Posted August 23, 2014 Posted August 23, 2014 Servo means: a motor (DC normally) with feedback. There are essentially two kind of servo motors: digital and analog ones. The digital ones get digital feedback and the analog ones analog. The digital ones might use for example a gray encoder to move into the correct position, the analog ones often use a variable resistor. You could build one using a normal DC motor, but remember that the feedback mechanism will take space too and there needs to be some kind of logic, servo's have a controller chip onboard. Quote
BusterHaus Posted August 23, 2014 Posted August 23, 2014 Would a Geneva mechanism do the trick? It offers a dwell time during which you can stop the motor. Quote
aminnich Posted August 23, 2014 Author Posted August 23, 2014 JopieK- I have a pretty good understanding of how electronics work, although I really don't want to have to build something for my MOC. If I need to I will know how to do it. Thanks BusterHaus- I did not know what a Geneva mechanism was, but I think that this might work for what I need it to do. The problem is, how would you make something like that with legos? I love the idea, but I am not sure how to make it. Quote
Phoxtane Posted August 23, 2014 Posted August 23, 2014 If you use the train remote with the servo motor it'll stay in place. Quote
aminnich Posted August 24, 2014 Author Posted August 24, 2014 I sadly don't have a train remote, and I really don't need to get one Quote
BusterHaus Posted August 24, 2014 Posted August 24, 2014 This is one design (not mine): http://lego-technique.blogspot.ca/2013/02/geneva-drive-in-lego-technic.html?m=1 You can find other designs with Google, but I can't vouch for any of them, including the one I linked to. From what I can tell the lock on the dwell has quite bit of backlash. I wish I had more info to offer but a Lego Geneva mechanism is still on my to-do list. Quote
Hrafn Posted August 24, 2014 Posted August 24, 2014 Check out Piterx' sequential gearbox idea (post #36 here). It's the most compact non-servo solution I've seen. Quote
Zerobricks Posted August 24, 2014 Posted August 24, 2014 You could use a switch that turn off the motor when it reaches certain position and some kind of a spring to move it to center position....I'm gonna try build it... Quote
Zerobricks Posted August 24, 2014 Posted August 24, 2014 Just built it and it WORKS!!! Video coming soon! Quote
Zerobricks Posted August 24, 2014 Posted August 24, 2014 Sorry for so many posts, I made the first protoype. Check this topic: http://www.eurobricks.com/forum/index.php?showtopic=99343 Quote
aminnich Posted August 24, 2014 Author Posted August 24, 2014 thanks ZBLJ for taking so much interest into my problem. But I have another problem my computer wont allow me to view videos on eurobricks, so it would be amazing if you could please post pictures, either here or on your post about the MOC. Thanks so much im sure it will work out for for me Quote
Zerobricks Posted August 25, 2014 Posted August 25, 2014 Cant do anything untill brickshelf is back online... I dont understand how you cannot see a youtube video though, sorry... Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.