admir
Posts: 3
Joined: Thu Mar 19, 2015 8:52 pm

Mechatronic task

Fri Mar 20, 2015 11:49 pm

Greetings,

Hello everyone, I am student of Mechatronics and i have a task from a company to design a sliding mechanism system which will have a DC motor and a belt mechanism (as shown on attachet picture) that will make a frame to slide. This mechanism will be installed over the cabine of a forklift. My task is to make the frame move back when the fork is lifting and move foreward when the fork is falling. The dc motor will be conected with the controller, and i thought to put two sensors on both extreme sides of the sliding frames so that when the frame moves in two extremes this sensors give feedback to the controller, and i thought to connect the lifting/falling button of the fork of forklift also with the controller so that when we push the lift button of the fork the controller activates the dc motor to move the frame back to prevent collision of fork with the frame. The two sensors in the sides of the frame give feedback to controller once the frame slides to the end of each side, and i thought to program the controller that way that if it doesnt receive feedback from this sensors from a certain time, it means that the frame didnt reach the destination and at this moment controller should stop the lifting/falling process of the fork.
What i needed is a raspberry pi SBC because they are cheap, but i dont know if it is possible to do my task using this SBC , because i have no experience with raspberry pi, and there are different models of raspberries and i dont know which one could do my task.
Can you help me with some ideas/suggestions,

Best regards,
Attachments
rsz_optimized-untitled.png
Forklift
rsz_optimized-untitled.png (47.74 KiB) Viewed 1048 times

User avatar
B.Goode
Posts: 9300
Joined: Mon Sep 01, 2014 4:03 pm
Location: UK

Re: Mechatronic task

Sat Mar 21, 2015 9:59 am

admir wrote:What i needed is a raspberry pi SBC because they are cheap, but i dont know if it is possible to do my task using this SBC , because i have no experience with raspberry pi, and there are different models of raspberries and i dont know which one could do my task.
Start with the most recent RPi Model 2 B for experimentation and project development. Once you have some experience of using it in your specific project you may find you can substitute a slightly cheaper Model A+ for your 'production' version.

lumsdot
Posts: 123
Joined: Wed Mar 11, 2015 5:29 pm

Re: Mechatronic task

Sat Mar 21, 2015 12:27 pm

An arduino board may be cheaper simpler and more suited to this task.

admir
Posts: 3
Joined: Thu Mar 19, 2015 8:52 pm

Re: Mechatronic task

Sat Mar 21, 2015 2:30 pm

Hello!!
thank you for reply, my university will provide me the hardware but i can not order more than one, so in this case i was thinking to order the A+ model and start working with that.

admir
Posts: 3
Joined: Thu Mar 19, 2015 8:52 pm

Re: Mechatronic task

Sat Mar 28, 2015 11:24 pm

Hello!!
I changed my mind and decided to buy RPi 2B but i was searching for switch sensors which i need to give feedback to the Rpi, but couldent find any link from people who had used this kind of sensors with RPi , i thougth to buy this one:"http://uk.rs-online.com/web/p/detector- ... s/7582124/" (100 mA @ 12 V dc maximum),, but i am not quite sure if it can be adopted with the Rpi GPIO pins which i read they draw only 16mA , i read that Rpi GPIOs have only 3.5- 5V output power, and i dont know if this is enough. Did you have experience with such kind of switch sensors, can anybody please help me with any suggestions.

Thank you and
Best Regards.

User avatar
Burngate
Posts: 6192
Joined: Thu Sep 29, 2011 4:34 pm
Location: Berkshire UK Tralfamadore
Contact: Website

Re: Mechatronic task

Sun Mar 29, 2015 9:25 am

That switch http://uk.rs-online.com/web/p/detector- ... s/7582124/ is just a switch.

"... a maximum switching current rated to 0.1A at 12Vdc ..." just means that it will break if you exceed either of those limits, but your Pi would have died before you reached them.
Your Pi will (if you connect it correctly) put 3v3 on it, and maybe a few mA depending on what value resistor you use, so you will be well within its limits.
(Of slightly greater concern - "... and a minimum rating of 50μA at 3Vdc" - the contacts on some switches oxidise and go bad if you don't put enough current through them. 3v3 is close to that, but using a 1k pull-up resistor should keep the switched current high enough)

Since the GPIO will be an input, its 16mA max output current is irrelevant

So hunt round and find a tutorial on how to connect a switch (or "button", which again is just a switch)

ame
Posts: 3172
Joined: Sat Aug 18, 2012 1:21 am
Location: Korea

Re: Mechatronic task

Sun Mar 29, 2015 9:35 am

Can you attach some string from the fork to the frame? Attach some pulleys to allow the string to go around corners. When the fork goes up and down the frame will slide back and forth.

Return to “General discussion”