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41
Misc / Pepper, the emotional robot...?
« Last post by mklrobo on June 19, 2015, 04:55:42 AM »
 ;D Hello!
Yes, its true.  :o The controllers of Sprint and owners of alibaba (industrial trading) have co-ventured to
make an emotional robot. This info alert off of a online report describes;
Humanoid robots named Pepper are envisioned as companions for the elderly, teachers of schoolchildren and retail or office assistants.    AKIO KON/BLOOMBERG NEWS
Just saw the newcast this morning; I am sure more info is to follow.....   ;)
42
Mechanics and Construction / Re: Electrical Rotary Joints with Stepper Motor?
« Last post by SiDawg on June 18, 2015, 07:23:42 PM »
I think i've found a solution... "hollow shaft stepper motor", for example like the one below (though this is very high voltage: surely something similiar available at lower voltage)

http://www.autonics.com/products/products_detail.php?catecode=03/01/02&db_uid=72

So you could mount that to base and turrent, and then buy a "slip ring", something like this:

http://www.moog.com/products/slip-rings/slip-rings-faq-s/

Mount that underneath the motor on the base... feed the wires through the middle of the stepper motor shaft, attach turret to outside of stepper motor shaft and attach wires coming out of shaft to whatever you like: they will free rotate as the stepper motor rotates (probably want some sort of "clutch" on turret, something fixed to turret that grips all wires together securely, so all the twisting force is limited to the gap between top of slip ring and point of that clutch rather than being transfered to where they're soldered to your parts.
43
Mechanics and Construction / Re: Electrical Rotary Joints with Stepper Motor?
« Last post by SiDawg on June 18, 2015, 05:57:13 PM »
Thanks mklrobo that's an interesting take on the problem! It would be quite a fun and interesting challenge to transmit power wirelessly... Then there's all the "information" or data lines going to all the sensors: I guess as long as there's power I could transmit via radio. Probably overkill but an interesting challenge :)

I'll check out the Thomas Registry! Thanks for the tip

44
Mechanics and Construction / Re: Electrical Rotary Joints with Stepper Motor?
« Last post by mklrobo on June 18, 2015, 06:05:27 AM »
 ;D Hello!
Interesting problem!
I would offer an opinion, where permissible.  :)
At first glance, I would check the Thomas Registry. This document holds all the
names of manufacturers in North America
. If it is manufactured in the USA, then
you can find it.  ;D
If not, you may have found a nich'e, in which invention is required. Depending on your amperage draw,
any number of answers spring to mind. Ideas are;
1> transformer on lower and upper half to transmit power.(no contact needed)
2> slip rings. (you thought of that one already)
3> laser emission. One side is emitter, and the other acts like a solar cell, to absorb power.
4> heat; one side emits heat, the other side has a thermopile, to convert heat to energy. (very unlikely to use)
5> generator around the shaft of the receiver arm. The driver arm moves the shaft in rotation; while that
is happening, a generator in the upper receiver shaft converts mechanical energy to electrical energy
to power whatever is on the receiver shaft.( :o ) I have to stretch to come up with that one!!!  :o
That is all I can think of at the moment.  Good Luck!!!  ;) :) :D ;D
45
Mechanics and Construction / Re: Electrical Rotary Joints with Stepper Motor?
« Last post by SiDawg on June 18, 2015, 02:15:16 AM »
... I guess how it COULD be achieved is a circular gear on the turret (or the base!) and the stepper motor has just a small gear feeding on that that... so in effect stepper motor off-centre of turret.

Then structural question... it doesnt look like slip rings are designed to really hold and secure a turret to a base for example so if the stepper motor can't be used to attach to the base and the turret (stepper motors seem "sturdy enough" for the weight im talking about) then some other structure would be needed to hold up the turret, provide bearings, etc... hmm...

It should definatley be possible to build a stepper motor and strip-ring in one: after all a motor has slip rings built in anyway right? Just add a few more and feed wires through the middle of a hollow axis...
46
Mechanics and Construction / Electrical Rotary Joints with Stepper Motor?
« Last post by SiDawg on June 18, 2015, 01:14:33 AM »
Hi all, my first post, thanks for reading :)

Basically my question is "how do you combine a stepper motor with a 'slip ring' or 'electrical rotary joint' so something can spin through and past 360 degrees without twisting wires?


I'm in early planning stages of a small (inside 20cm) robot: I started thinking about "fully rotating" turrets and how that could be achieved: I can find for example 12 wire 'slip rings' that take care of the "twisted wire" problem, but how can i combine that with a stepper motor? Is there a product that combines the two for me? Is there a slip ring with will fit over a motor axle? Is there something obvious im missing? Or is that just impractical and/or unnecessary?

So for example, my base/chassis may be a standard-config vehicle, two wheels with motors, plus a third or fourth free-wheel... No surprises.

But I want a 360 degree scanning turret: something holding range sensors, light sensors... i.e. "some number" of directional sensors.

I imagine the standard approach is to just rotate one way through 360 degrees, then back through 360 degrees... all the wires will just twist one way then twist back the other way... a stepper motor can be housed on the base and the turret attached... But obviously if you wanted to go past 360 degrees, then all the wires going to/from those sensors would just keep twisting until they can't twist no more...

Thanks for your help
47
 :) Hello!
First, I, in no way, implied that you were stupid. I have had the same problem as you. I need help
with the programming, no doubt.
When I saw this forum, and read some of the posts, and the tutorials, it seemed easy to use the
Axon series. I invested a lot of time/money/effort in order to understand and program the Axon.
You are right, if you can not compile the Hex file, the robot will never work.
I have worked with small MCU's like this, and I am still stumped.( :-\  ) I may have gotten a virus,
downloaded something wrong, or whatever. I have found info pointing to a direct way to compile
the object file to a hex file, but have been unsuccessful in making it work.
In reference to your videos, I would definitely do a dry run first, maybe making notes, then go through
with your video.
I believe other people are having the same problem, that is probably why you have not seem many
people respond to your posts. (and mine).
Once this problem is resolved, and other people see your video and my posts, that will pretty much eliminate anyone having any problems starting out. After that, more people will be encouraged to use the Axon, and post their projects on this forum.  ;D
 8) I do not wish to discourage anyone from using the Axon. It seems problematic now, but it is being used everywhere, and is a very versatile MCU. If I knew the answer to help you, I would definitely tell you.
I am still working on the problem, even though I feel Hexed.  ;)
48
;D Hello!
A most excellent idea, to contact Admin. He has responded to one of the questions on my post.
I consider myself to be computer literate, and have made some programs for other types of boards
myself. I am not an expert in this by any means, and have started from scratch with this type of
MCU (Axon). I made the post to help a lot of people work out the issues that they may have with the
axon. I went ahead and bought a bootloader; in which, in retrospect, should allow me to program
other boards that do not have the bootloader capability of the Axon.
I reviewed the datasheet on the Axon MCU, and I think, that it is one impressive MCU, capable of
a lot. I have not seen anyone, lately, (and not much in the past) fully explain their projects from
code to construction, or the features of the Axon that they took advantage of to obtain their goal.
This is another reason I started my post. When I, or you, break through the HEX conundrum,  :P
I think you will see a lot of people come forward with their projects too. The only thing left is
to make programs that take advantage of the features, so that anyone can use those "snippets"
of code to learn/use in their own robot. ;D
Ok, I'll make sure to contact admin when I finish the 50$ robot (if I can finish it, hehe) and make a list with all the things I didn't understand at first, to help all other newbies. I mean, it might look stupid to robot builders like you, but I didn't even know what a microcontroller was :) When I had the parts (without the board) I spent more time than I'd like to admit trying to connect the servo to something that fit to upload the hex file heheheh ;) Anyhow, if I can't program it using the .hex file, I will try to modify the servos mechanically, by googling or asking how to do it. Anyway it turns out, I think I'll make a video explaining the process. I'll do whatever method works with the first servo, and then film myself doing it for the second one. What do you think?
49
Misc / Re: Analyzing the Axon series: Coding, Construction, and Contraptions
« Last post by mklrobo on June 17, 2015, 07:07:00 AM »
Axon Series: What is this thing?
It is ALOT of work getting into programming the Axon. :P  BUT, the rewards are more than I
realized. I found that my washing machine does have a MCU very similar to the atmega line
of processors.( ;) could make my own washing machine controller!) Electronic setup is very
similar, on the control board. ;D I also found an Atel MCU on a control board, that controls
a generator switch panel!   ;) There is no telling where else this line of processors are!   :-X
To get some real world programming code, I could extract the code from machines that have
these processors, and look at the code to see how they used the internals of the processor, to give me a better understanding of how to program these types of MCUs.  8) Cool!
When you download the AVR studio and Webbot package, you get access to the entire line of this type of MCU's, plus a simulator to run the program (virtually) in AVR Studio. You can use the hobby of the Axon programming to decipher the internal workings of machines that have the processor. ;) An added plus, is that if you buy a hardware bootloader, you can program the whole line of these processors! (I think,  ??? )
I will try to read the switch panel MCU controller; hopefully they did not put a "lock" on the processor. :'(
50
1)
identify the power requirements for each of your components. if you require different voltage levels (i.e. can not use 5v for everything) you may need to build a regulator board (typically a linear regulators for each of the voltage rails would work for a project like this). arduino boards have an onboard linear voltage regulator. you do have to be careful not to overheat linear regulators as they are not very efficient especially for regulating down larger voltages.

typically you want to handle the motor power a little bit differently, it is higher current and can introduce noise into the rest of your system (causing problems). most motor controllers have separate power input for the motors and control. one option is to use separate power sources/batteries. it is also common to power the motors directly from the batteries and rely on the power supply to your control electronics to filter the noise. good design practice would include some filter caps to help with this.

2)
there should be arduino libraries to help with this and likely some example code. simplified: a command in your code will read in the signal from the receiver and store it as a variable. you can then do some calculations with those values and then another command will send a signal to the motor controller.

3)
the need for a heat sink depends on the power your components are dissipating. typically it is the higher powered components that are a concern (voltage regulators, transistors in your motor controller/h-bridge). the regulator on the arduino is not very big so be careful how much you run off it. you will have to look at datasheets and understand what specs you are using the components at to get an idea how hot they will get. it will not hurt to cool your components with a heat sink tho. one way to find out if you need to cool your components is to test them and see if they get hot in your application (you might destroy a component but often components are cheap). careful not to burn yourself and buy a few extra regulators ect.

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