Need a circuit diagram for running the Propeller QuickStart board on Battery Power
Cliffo
Posts: 12
Dear Parallax Support,
In reviewing the end of this web page:
http://www.parallaxsemiconductor.com/products/quickstart
I read about Vin, which Id like to drive with 4 NiMH batteries to provide 4.8 volts.
Will this be a sufficient voltage for proper operation?
Will I need the AAA or AA size to provide 10-20 hours of use?
So I can wire this up correctly, please post here a circuit diagram for attaching a battery, so I will no longer need to power the board from the USB port.
Lastly, once I have the battery wired up, do I need to disconnect it each time I connect the USB port to my computer?
I.e., for battery-driven use, do I need to permanently connect /USB_PWR_EN to either Vdd or Vin?
Thanks,
=Cliff Olling
In reviewing the end of this web page:
http://www.parallaxsemiconductor.com/products/quickstart
I read about Vin, which Id like to drive with 4 NiMH batteries to provide 4.8 volts.
Will this be a sufficient voltage for proper operation?
Will I need the AAA or AA size to provide 10-20 hours of use?
So I can wire this up correctly, please post here a circuit diagram for attaching a battery, so I will no longer need to power the board from the USB port.
Lastly, once I have the battery wired up, do I need to disconnect it each time I connect the USB port to my computer?
I.e., for battery-driven use, do I need to permanently connect /USB_PWR_EN to either Vdd or Vin?
Thanks,
=Cliff Olling
Comments
Yes, four NiMH batteries will power the QuickStart just fine.
I soldered two male headers to Vin (position 40) and Vss (position 39) holes. I then use a battery back that holds four AAs to power the board.
As for how long the four batteries will last that depends a lot on what you're doing with the Prop. My guess is 10 hours would probably be okay.
You don't need to worry about /USB_PWR_EN when powering from a battery.
I frequently have both the batteries and the USB connected. I haven't had any trouble. To play it safe, you might want to use a USB hub.
I'll see if I have a picture of how I've wired mine up and post it here.
You can see I also soldered female headers to the five Vss and five Vdd (3.3V) holes on the far right. I find these headers make it easier to add 3.3V devices to the QuickStart.
With two active cogs it draws about 40mA. My Eneloop batteries I have list a capacity of 1900 mAh. Which should provide power for 47.5 hours. I'm not sure if you'd really get this much time out of them on a charge but you should be safe for 20 hours.
Here are some other QuickStart links.
A collection of QuickStart projects.
My QuickStart Roomba.
QuickStart servo tester.
I know there are a bunch more.
There's a potential for something to go wrong...
I put a diode between Quickstart and battery so that current only goes one way...
Hello!
Duane, I dislike replying to a thread that's old enough to start shaving, but, ah, I'm curious. Who's pins did you use for that?
I used positions 39 (Vss) and 40 (Vin) to add the headers for the battery connection.
I was using four NiMH cells in the battery pack. The four cells fully charged produce about 5.5V. I think the QuickStart's regulator can handle voltages up to 9V (or more). Since I often have 5V devices I'm using with the QuickStart, I try to keep my power source close to 5V. I use these cheap switching regulators with some of my projects.
The labels "VDD" and "VSS" between the two male headers and the block of eight female headers are labels for the female headers. You can use these eight positions as four power connections to 3.3V devices (like the nRF24L01+ module shown earlier).
When powering the board from USB, positions 39 and 40 can be used to power low current 5V devices (servos are not low current devices but I've managed to use two micro servos with a large capacitor when powered from a USB hub (for some reason that hub no longer works)).
To double check:
Diode goes in red wire between battery pack and QuickStart Vdd. Black band on diode case goes towards QuickStart.
Thanks.