Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: pomprocker on February 09, 2009, 12:50:45 AM

Title: Battery, Charger, Battery monitor, and MCU Circuit
Post by: pomprocker on February 09, 2009, 12:50:45 AM

Could someone advise how to build a circuit like this:

             Charger
                    |
                    v
Battery-------><-------MCU
                    /\
                     |
     Battery Monitor Sensor


Obviously the battery is plugged into the board, and then the Battery Monitor Sensor taps that connection and sends its results to the ADC on the board. Then I want to be able to add the charger to that mix, and let the battery charge while the MCU remains on.

(Self Docking robot)

Title: Re: Battery, Charger, Battery monitor, and MCU Circuit
Post by: Soeren on February 10, 2009, 04:12:33 PM

Hi,

Do you want the charging circuit (less transformer) to be a part of the robot or part of the docking base?

If you've got an A/D-C port or two to spare, the controller could handle the brains of the charger, but even if build with discreetes it might be an advantage to place it on the 'bot and just plug into a lead (with a relay on the base energized by the 'bot to feed mains power to the transformer only when needed.

Title: Re: Battery, Charger, Battery monitor, and MCU Circuit
Post by: pomprocker on February 10, 2009, 06:43:17 PM

I would like to build a charging base for the robot like a roomba. I was thinking about using this conductive tape I have and place some on the charging base as well as the robot. So the robot would drive into the charging base by itself and start the charge cycle. When it is complete it will then drive off on its own.


The base would house the charger itself, I was thinking of making an adapter (tamiya connector to conductive tape)

The conductive tape on the robot's HDPE chassis would be wire up to the battery, which would also be wired up to the MCU and the battery monitor sensor.

I'm afraid though that the charger would fool the battery monitor sensor into thinking the battery was full. I also don't know how to implement this circuit, whether diodes or what not is needed.

Title: Re: Battery, Charger, Battery monitor, and MCU Circuit
Post by: Admin on February 15, 2009, 05:44:50 AM

Quote

I'm afraid though that the charger would fool the battery monitor sensor into thinking the battery was full. I also don't know how to implement this circuit, whether diodes or what not is needed.

Use timers! For example, after it enters a charger, have it timed to charge X number of hours.

As for the circuit . . .

battery -> voltage sensor -> ADC of microcontroller

and

battery -> voltage regulator of microcontroller

When you draw out the schematic, you'll kick yourself how easy it really is.