Homemade Biped Robot

@JeffMorris, we originally looked at using a jumper for alternate power source, as you can see the space on the board for it is labelled "EXT PWR SEL". However, those jumpers are only rated for 1 amp, and had huge resistance. The jumper was removed. You can provide alternate power by modifying the EZ-B and cutting the EXT PWR SEL trace on the bottom of the PCB.

By cutting the trace, the pins D0-D14 are seperated from the EZ-B's internal VR. Power can be applied to the top 2 pins (above D14) labelled EXT PWR

The forum is configured to display messages in Date/Time order. Original message is first, and every message is added to it - so the last message on the last page is the most recent post. It's the default way for all forums.

You may be able to add a fan to the EZ-B's internal VR heatsink - as i usually do and many others on here. A small 3cm fan works great. Here is a photo of how I usually do it. Keep in mind, the VR on the LEFT of the PCB (closest to the power connector) is the VR you wish to cool the most. I power 12 servos in a biped and hexapod using a small 5volt 3cm fan.

Good work with your project!

@jeffmorris if you are handy with a soldering iron you could both cut the trace and install a jumper option for your own use... (Do so at your own risk!... probably voids what warranty there may be). I modded my board this way and it works great

Oh yes... be aware it is a double sided board and you might need to solder both sides. The tricky one is on the top side (right under where the jumper goes...)

I think that I ruined the EZ-Board by cutting the trace. If a servo is connected to D0 port, nothing happens. Servos connected to D1 and up ports work. How can I fix it?

Thats weird. If one ports power is working I imagine they all would this is why im not keen on modifying the board when the power can be provided externally. I hope its not messed up.

With the EZ-B unplugged from power try testing continuity between ports D0-D14 5v line (the middle one) and the EXT PWR pin. Then D15-D19 and the 5v pin over by the ADC ports. Then make sure there is no conductivity between both sets of ports (D0-D14) & (D15-D19). If anything, I had trouble making the cut clean as it sometimes allowed a small current through, something you don't want with two power sources feeding from each end. Hope this makes sense... just a quick post from work

Hello Jeff, any further info on the issue you had?

After cutting the trace were you running D0-D14 off of EXT PWR when you noticed that D0 was not working?

Can you show any close photos of the cut you made?

And any other details you can provide will help us troubleshoot what may have happened.

I accidentally cut the trace for D0 and another trace at the edge of the board. I think I ruined the board trying to solder a piece of solid wire to the D0 trace. Is it possible for me to exchange the board for another one?

Oh, sorry to hear that. There is always an inherent risk of damage when we as hobbyists attempt to expand and modify our toys

As far as purchasing replacement parts or other options, I would suggest you take up that discussion with the staff (I am just a fellow client and hobbyist myself). DJ might weigh in on this topic or you can try this link to their contact page CONTACT

Don't Panic everything is usually repairable or salvageable... and sometimes that is a required part in our learning process with these techie hobbies and ventures.