Are you saying you’re PARALLELING drivers from different boards? What chips? Normally, you only parallel drivers in the same IC package.
Layout doesn’t look bad.
Did you do DRC (design rule check)? I always like to put in mounting holes, preferably in the corners.
I’m not seeing bypass caps on the XBEE and other ICs. Also a good idea to add bypass caps on the motor power lines. The Propeller doesn’t need any caps on the 5MHz Xtal?
Alan KM6VV
Each chip will will be running it’s own motor, I’ll only be paralleling drivers on the same IC. They are stacked to share inputs and and power pins.
The prop doesn’t need caps on the crystal but I do know that I need to add some decoupling capacitors for the xbee and prop, probably for the drivers too. For the motor power lines, do you mean I should add caps between the +and- for the motor outputs?
yes a capacitor that goes in parallel across the power supply terminals of anything is called a bypass capacitor.
The value…that’s really up to you. Try to pick a larger value since it will better smooth large motor voltage spikes. Larger capacitor values also filter out low frequency noise better.
The capacitor you use should be rated for at least 2x the voltage the motor is running off on. 4x is preferrable. Otherwise the voltage spikes from the motor will destroy your capacitor very quickly.
Here are some things you should know:
-If you just need the capacitor to filter out motor noise, they can be quite small.
-However, if the capacitor is for a motor controller (to take pressure off the battery and provide power when there are voltage dips), then your capacitor will have to be much larger.
Caps on the power supply to the driver chips.
Jonny has indicated the caps (I use 2 or 3) on the motors for EMI reduction.
Alan KM6VV
So I’ve been doing quite a bit of ordering. I’ve got all the components for my board and now just waiting on the board itself to arrive. I’ll post some pics next week. I also plan on ordering the rest of the parts tomorrow (batts, servos, SES parts, other materials). I’m getting very excited to really start getting into this. Ambitiously, I hope to be able to have the entire thing built by the end of June 
. Then the programming fun can really start! 
I do have a question though. What size batteries do you guys run in your bots? I’m looking to put around 3000mah in this.
My boards came in last night! I was excited to finally put it together. It’s just about finished, just need to trim up and solder one of the motor drivers.
Look great!
Kurt
Wow… That’s a really nice board.
Look forward to see it work.
I will maybe try to use my arduino mega on my quad…
Nice board!
fully professional.
but is it cost effective? for example in case if you’ll need to change design somehow
Cost effective? Mehh.
I don’t think it was that bad. It came out to almost $70 with shipping to get 4 of these so it was around $17 per board. Add about another $80 for the motor drivers, xbee, and other components and it’s about $100 for a complete board. Yes, it’s more expensive than most manufactured boards but it has exactly the functionality I wanted and it was fun designing it.
What board house did you use?
Alan KM6VV
that’s the point 
So I’ve finally found some time to start machining. I made a few parts last night for one of the legs. I’ve got a few holes I need to drill for some threaded rod then I’ll be able to assemble. I’m hoping to have a completed pic up sometime tonight.
They turned out pretty good for the most part. I may need to find a different way of holding the small disks when machining because they didn’t turn out as round as I’d like.
Nice machining! Almost looks like wood. What material?
Alan KM6VV
Thanks!
I used this: alumilite.com/ProdDetail.cfm?Category=Casting%20Resins&Name=Alumilite%20Regular
mixed with
alumilite.com/ProdDetail.cfm?Category=Dyes%20-%20Fillers&Name=Microballoons .
It’s really light and has good strength. Its nice to be able to pour the blocks to whatever size I need.
Thanks for the URLs. Interesting stuff! I think someone else on this list had mentioned it.
I haven’t tried it, as I usually just machine the parts I want.
I might have to try some!
Alan KM6VV
No problem. Give it a try, it machines like a dream. No melting or anything to worry about like regular plastics.
Boy, this is a lot of work!
Two days of machining and assembling and I’ve only almost produced half of one leg. Ha 
Close, though. I need to counter bore some holes for clearance and trim down some of the threaded rod. Then, I need to add the “foot”: just some 3mm hardened steel rod coming off the top.
So far so good.
