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hmartiro / project-thesis

xJüs, the hexapodal robot with a passive-backbone to improve behavior over harsh terrain.
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Create "Hot Swap" Interface #75

Closed PayneTrain closed 11 years ago

PayneTrain commented 11 years ago

Drawing from the UPenn "Technical Paper" in the repo, implement a logical OR that allows us to swap out a dying battery with a fresh one without causing the system to lose power.

PayneTrain commented 11 years ago

Very helpful

Basically just place a diode in series with each battery to keep a voltage difference between dead and charged battery from creating a huge spike in current

PayneTrain commented 11 years ago

Looking into this chip

Emailed Linear Technologies (didn't respond to my call) looking for a simple diode (rather than a embedded 2-channel system that would need a controller input)

hmartiro commented 11 years ago

lets make sure this doesn't happen :+1: https://www.youtube.com/watch?v=B-AoAYrEy-o

PayneTrain commented 11 years ago

Bought these diodes (will chain two) see the below email from linear:

No micro required with LTC4414. It also withstands -14V. If you need more protection, use this: http://cds.linear.com/docs/en/application-note/an107f.pdf

The LTC4414 should be perfect for this project. They will probably need to use 2 back-to-back FETs for each battery channel. In this case, the “Aux” power is the “primary” battery.

Regards,

PayneTrain commented 11 years ago

This is the circuit, just working with LTC to get the right external PMOSs (x2) and then PCBExpress to get our circuit boards.

@towlett I'm planning to have the new circuit layout to you by Saturday, does that work for you in terms of creating the new middle plate?

LTC4414 Circuit

towlett commented 11 years ago

Sure that works. As long as we have all the components so that I can measure holes, I can update the middle plate and get it done over break or immediately afterwards.

PayneTrain commented 11 years ago

The board should be here Friday unfortunately I'll be gone at noon so will have to install it Sunday Night/Monday:

I'm closing this issue now but if we choose to do another iteration of the board (~$60) then I would try to add a power switch and Tamiya connectors as found on the EduBot.

xJusPower_Full

The red is what is visible to the user: xJusPower_Top