Circuits

[sho]

About Circuits

[jmccartney]

(04-19-2014 03:27 AM)sho Wrote:  About Circuits

Any strong opinions regarding shellmo circuitry. I imagine a lot of people will use whatever they have on hand which makes the most sense. I am getting burnt out on sketchup so I am going to spend a few days tinkering in Eagle Cad with some ideas for my own shellmo board.

Probably going to base mine off of the ATmega32U4 in a TQFP44 package. Thats about the most I can push my reflow skills on a hotplate. I am also looking into mosfets to replace the transistor that Sho described using for the biowire and will be easy to substitute servos instead if need be.

[steamboat]

After finishing my RA04 design, I am also thinking about making a PCB. OK, the Arduino is cheap (10 Euro) and you get everything you need. But when it comes to wiring, it is a piece of work and chaos. Think about all the +/- 5 volt cables to servos, eyes and switches. I think about selling some left over RA04's after the MAKER FAIRE on ebay just to cover my costs. For this I need an easy and cheap to build PCB. By chance I have about 80 ordinary ATMEGA328 in the shelf but this is not a must. I am not the reflov man...

You could use an Arduino as USB connection between your board and the PC. But I am sure that you have good solutions.

So my first PCB must be a power and signal distributing PCB. It also could become a shield?

I want to connect some sort of ARDUINO with
2x servo for muscles
2x revolution "detectors" for syncronus/asyncronus run of the legs
2x or 3x servo for eyes
2x or 3x bumper switches at the front
2x or 3x bumper switches at the back
battery connector
On-Off switch to cut off the servos from the "main line" for tests. That should enable you to run the Arduino and all it's sensors on USB without a battery/extra source of energy.

Additional I think about
some push buttons to tell the unit what to do
- switching from autonomous to watchdog or BT behavior
some LED to indicate some status
a LCD?

Plus we can discuss other sensors:
a magnetic field sensor - have just some left overs frommy quadrocopter

Are such boards on the market already?

With this it would be easy to give the RepWalker/Shellmo away to other people which have a focus in programming and not in building or soldering. For me people with programming but not hardware hacking skills are a (small) market for this.

I also would like to give some of this to my daughters school but for this it has to look a little professional and easy to understand - not a piece of wires...

[jmccartney]

(05-11-2014 06:11 PM)steamboat Wrote:  I want to connect some sort of ARDUINO with
2x servo for muscles
2x revolution "detectors" for syncronus/asyncronus run of the legs
2x or 3x servo for eyes
2x or 3x bumper switches at the front
2x or 3x bumper switches at the back
battery connector

Yes this has been on my mind for a while now. At first I started designing a new board and after about 10hours of design work I felt like maybe I was going about this a little backwards.

One thing is you can get Leonardo boards on ebay from china at 10us bucks...so I am starting to think a shield might be better...and more versatile to a end user...

I love reflow though...so we are going to differ a lot here. China PCB turnaround is like 20 days for me here in the US. I use 805 components and no dfn..I feel this is easier than soldering by hand honestly..

I am posting a pic of my orignial desing 8x mosfets, atmega 32u4 and 2 pololu sockets for drivers.

[jmccartney]

(05-11-2014 09:28 PM)jmccartney Wrote:  I am posting a pic of my orignial desing 8x mosfets, atmega 32u4 and 2 pololu sockets for drivers.

I am going to somehow make a simplified version of this into a shield maybe...but we should keep this dicussion going. Some basic requirements list would be great to start.

[jmccartney]

I do not mind making the PCB and doing the reflow work by the way and sending them to you guys, but I need a lot of design oversight so we don't go through a million versions...

Also as a 50 day turnaround is going to be cutting it close

Probably looking at 15 bucks a board total...idk. rought guess..

[steamboat]

(05-11-2014 09:36 PM)jmccartney Wrote:  I do not mind making the PCB and doing the reflow work by the way and sending them to you guys

Sounds great maybe I also could learn this reflow work from you - I like input!

If we are doing a sheeld, and use servos only we even don't need any intelligent components and no reflow...

Using a atmega 32u4 would make everything smaller and maybe less power consuming. But it should stay totaly arduino compatible.

By the way I just remember this board in my shelf which I used sometimes as an AVR programmer...


Don't know how to use this because I baught this as programer only and put the given software on it with Atmel Flip like filling up your car with gas. James - can you direct me how to make it running like an Arduino?

---

Here is a link to the layout:
atmega 32_u

[jmccartney]

(05-11-2014 09:50 PM)steamboat Wrote:  James - can you direct me how to make it running like an Arduino?

I would just use the ISP sketch on an uno and wire them together and burn the arduino boot loader.

These instructions look good:
http://g11l.com/content/loading-leonardo...4-breakout

[steamboat]

(05-12-2014 05:06 AM)jmccartney Wrote:  These instructions look good:http://g11l.com/content/loading-leonardo-bootloader-adafruit-atmega32u4-breakout

Thank you - will try it after having the eyes ready for Thingiverse ... First pair is already in print in the moment.

[jmccartney]

Discussions regarding a Shellmo shield or "brain" circuitry has been moved to a new thread: http://shellmo.net/thread-136.html