Robotic students - Need help

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[elisom]

Hi every body, sorry for writing in English, my Greek is pretty bad.

I am building now prototype for my robotic modular arm, https://www.youtube.com/watch?v=kesImjNqyN0

I finished to build it and its work now manually with up-down switch for each piston. I would like to connect it now to computer and i need a student to help me with this.

(i will pay of course the expenses and some small amount for every work hour)
So, if somebody interesting, please let me know.

(my place is in Ippokratio)

I am available in the email, skype (elisom) or on mobile 6948036444

Thanks a lot
Eli

[4Dcube]

If you got plain switches to handle, you will need extra hardware, e.g. a microcontroller that connects to PC.
You have to figure out the response time that you need the arm to have. It is affected by communication to PC.
Depending on how many switches and how fast communications you need, the microcontroller will be chosen.

After that, you have to decide where you will close the control loop of the arm. That is, how will you know where the arm, or its end, is? Will there be a controlling algorithm written in microcotroller's embedded code or will you write a driver on the PC? That design choice is affected by the communications in a recursive style.

Anyway, my guess is you will be carefully ok with an arduino and even better with a raspberry pi.

[elisom]

Thank you very much.
I guess the code will be on the PC and i will buy all the hardware that needed.

Until now i finished only the hardware and the base electronics.

[4Dcube]

Whoa, it's big
Congrats for building it.

So, you have 8 switches. That means you need 8 pins of the microcontroller. These output pins drive the switches with the help of transistors in a switching circuit.
Set the arduino at 1Mbaud, and talk to it via USB with a script on your PC (virtual buttons or commands) and you are set.

If you don't mind me asking, why do you need this?

[elisom]

Right now i have 8 switch with up/down/neutral.

I am doing it as prototype for my patent.

Check the YouTube up

 

[4Dcube]

Oh, so the switches can go up, neutral or down... This means you need 16 pins. Not really a problem.

[elisom]

I am not sure that 16 is enough but i don't have any experience. right now every switch have 6 connections so it is 48, but i guess it can be done also with 16

[4Dcube]

6 probably means 3 pairs of short-circuited contacts
1-up
2-Vcc or Gnd
3-down
You need to control 1 and 3.
So, 2 pins per switch, total 2*8=16 pins to be controlled.

[elisom]

The pistons works with DC, up - when + connected to + and - to -, and down when the opposite, so i think need 24 switchers to control, but i am not sure. 

Anyway i still looking for somebody that wants a bit work...

[4Dcube]

Then you don't need plain switches but h bridge ICs to control the motor direction.
If you use only switches you'll burn them.

[elisom]

Yes. i using 6AMp  dc so simple switch will not work.

maybe something like this

[elisom]

i guess this one is good
http://denkovi.com/usb-16-relay-board

[4Dcube]

I don't like relays... Too slow, too much space and too much power consumption...
You built a robotic arm, not a crane, right?


Well, it depends on what the use is...

[elisom]

There is no use for it... It's just an ProtoType.

What else can i use?

[rspappas]

personally I like darlington resistors (ULN2003 and such) for such operations.
if the pistons require lots of amperes to operate (darlington operate well up to 1.5A and 50VDC typically), then you might consider other, more potent, power switching transistors