GoalHaving multiple off shelf devices can make some things easier. But have a car battery of 12 volt doesn't fit on all of them. Converting 12 volt to a number of required volts:
- +5v for IP camera's and Arduino's
- +5v positive and -5v negative for robot arm (?linkje naar project?)
- +7,5v for network switch
- +12v (no conversion) for motors (shoulders, feet, neck) and used for Pico PSU for secondary computer.
- +19 for laptop power-supply (E-Bay car adapter)
The first four did pose a challenge as they did take up Ampere! A quick count came to 8 Amp!! And overload must be avoided, specially the arms could use good part. So have a 10 and 5 schema to be sure. The motors will draw directly from the batteries.
Drawing BoardFirst found an 10 A negative and 10 A positive schema for converting the 12 to 5 volt. Then a simple regulator (7,5 volt) schema. All thanks to CircuitOnline, a great dutch elektro website.
|The positive side|
|The negative side.|
|The additional 5 Amp|
The choice was to used an older PC power-supply as case. It has a fan, lots of holes and spacey.
|Running some tests|
|Ready for first test!|
For details on first attempt see below. But it is fine to skip that.
|After First Attempt, measuring the damage...|
|All apart again!|
When using the MJ2955 or MJ3055, I forgot to use mica (isolation)...Because if using the same they can share the ground (which is the body on MJ2955). But with MJ3055 this causes short circuit!
|MJ3055, which was fried|
So this cost some additional time, but also made me redesign and clean up wires.
In the end everything was fine. All measurements were in the green and the power-supply was good to go!