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Hi All.

This looks like what I need to build a full-sized Dr. Who K-9 from scratch.

I am a total noob when it comes to building electronic things however.
The main concern I have is how to power everything with a 12V battery correctly.
I will need it to run the wheel motors (looks like I need an additional part to do that), the sounds, lights, motorized antenna, ear and tail servos, a large lcd panel, move and activate a laser pointer (he's got a 'nose gun'), plus power the main ez robot board. I will probably add the distance sensor for collision avoidance and might try to add the camera if it's small enough. When not autonomatous, I'd like to control the robot by a remote control (? if the Wii would do this without a wifi connection).

I'm uncertain how to go about tacking on these components without frying something (do I have to add resistors?) and was wondering if there's a website that explains this in a step by step fashion. The astromech building sites don't seem to go over that and the K-9 building sites really don't talk about how to put ALL the electronics together (only the pieces). I did see some posts about modding the main board to accept an different power supply, but the main concern I have is understanding how to power the whole package correctly.

Can someone point me to a good website that would help me understand this sort of thing? I knew I should have paid more attention in high school!:p

thanks in advance,

Frank

PRO
Synthiam
#1  
I think you foun the right place:)

It'll actually be quite simple with ez-robot parts. And everyone here helps out often. What's your plan for the chassis? Share what notes you have for that, and the rest is easy.
#2  
Hi Frank, and welcome to the site! I love K9 and have one of the 11 inch remote control ones I want to modify with EZ-B. I think all of your questions can be answered on this site by other community members. We all share a love of building robots and DJ's EZ-B is the perfect device to make this come true. The EZ-B can take up to 14V and most of your devices can be powered right off the EZ-B. I would recommend a step down regulator to drop the voltage to 6V for the other items that can't take 12V but need more than the 5.5V the board puts out.

Bottom line, the EZ-B is a GREAT place to start!
#3  
Thanks for the quick replies.

I think the need for a step down regulator is the sort of information I'm after.
If there's a website that goes over this sort of thing in general (robot /electronics building 101), I think that'd help me understand the process / thinking a little better.

I need to understand the simple things-- for example, do I just run everything in series (vs parallel)? Do I need to be concerned about how much power goes to the next component down in the series? Do I need to measure that with a voltmeter for each component down the line? How do I know how much power is ok for a given piece of electonics if it doesn't say it on the package (eg. the motorized car antenna), how do I route the power from one component to the next (ie what wire do I solder to what)... Whew! Maybe this is not supposed to be that hard-- if all the components were powered with multiple wires coming out of the battery (like an octopus), it would make things easier conceptually, but I've never seen electonics powered that way.


---

With regards to the build:

I'm going to use the plans from Dave Everett. He's got a fairly screen-accurate dog. (Unfortunately you'll have to log in to download the files). At the moment, there's a good description of most of the individual components, but not how to put things together (and I'll be slightly varying from his plans anyway, with the EZ Robot additions).

http://k9.replicarobots.net/index.php?view=category&catid=1&option=com_joomgallery&Itemid=56
In the file about the base, Dave metions he uses 2 Jaycar gearmotors: http://www.jaycar.com.au/productView.asp?ID=YG2738. It appears to be powered by a 12V 7AH battery.


The dog ends up externally looking like this build: (I don't think the electronics are done the same way though and I've seen a lot of variations from different people (scooter motors being used, etc).)

http://www.therpf.com/f9/doctor-who-k-9-tin-dog-build-119847/

Here's a couple others who also did excellent work:
http://myuntemperedschism.blogspot.com/2012/03/k-9-build-days-1-and-2.html
http://darthmoose74.blogspot.com/search/label/K-9?updated-max=2010-12-05T10:54:00-06:00&max-results=20&start=20&by-date=false

Interestingly, no one that I've seen ever did what DJ did with his autonomatous K-9. The others are all remote controlled. I was really impressed and that's how I got to this site. I'd love to make a K-9 that wanders about and comes when called (I can't get my own dog to do that so well :)).

Frank
#4  
Fraaaaaank! Welcome to EZ-Robot

Im Josh and ive been a member since January. Ive learned so much from EZ -Robot and I am still learning so I am sure you will have fun on the site. If I can recommend anything besides using ez robot ofcourse , is to use as many premade parts as possible. This takes out tons of guesswork and frustration. For a small k9 the rover in the store is a great option and ive tested it with 25 pounds before and it ran like a champ. A 12v 7ah battery weights 6 pounds to give you a point of reference. If you dont want tracks you can swap the hubs for rubber wheels (but tracks are great :)) For a large k9 the 6wd wild thumper chassis is the way to go. It may seem pricy but if your building something that large its really about half what it takes to build the same platform yourself and no headaches.

Answering your power question - you will have everything wired parallel. The only time you would series components is to bring them all into one circuit. For example you have 6 leds at 2 volts each , wired in series it takes 12 volts to power them.

Ezb has a built in regulator so running a 12 volt system is fine. Also the rover and wild thumper chassis motors are great on 12 volts too.

In short I recommend building it inside to outside unless you already have a shell your working with. You will havr endless questions so just take a deep breath and ask them as you go. There are lots of helpful members to guide you along the way.

-Josh S
#5  
Hi Frank....Welcome to one of the most helpful sites I have ever been to.



Here are some links to electronics training sites that I have come across that also may be helpful to you. On some of them you may have to register.


http://www.doctronics.co.uk/design.htm

http://www.allaboutcircuits.com/

http://www.talkingelectronics.com/te_interactive_index.html

http://www.williamson-labs.com/

http://www.electronicsteacher.com/tutorial/

http://101science.com/eleclinks.htm

http://www.electronicstheory.com/

http://www.science-ebooks.com/electronics/basic_electronics.htm


-Rex
#6  
Thanks, All.

I also found the book, Robot Builders Bonanza, which looks to be pretty good.

Frank