Hello guys, my name’s Vincenzo and i would like to have an opinion before to place an order on Pololu.
I want to create a robot with raspberry pi and picamera. The robot can be controlled over a website (or C/C++) application stored in the apache folder on the raspberry pi through internet connection. I have a couple of question because i don’t know how to make the connection and what to buy to make it work.
Here it’s what i already have at home:
Rasperry pi B+ and also Rasperry pi 2, i was planning to use the 2.
I was planning to buy this for the motor: https://www.pololu.com/product/2753, but witch motor i have to connect? Only 2 (front or rear?) or 2 in parallel for each channel?
Then i was planning to buy this to power up the rp also: https://www.pololu.com/product/2119, is 1A enought to power up the rp + wifi + camera + motor without using the power bank?
The robot platform provide a battery pack for 5 AA battery, but what is the best source that i can use for this project?
It looks like the motors in that chassis kit have a stall current of 2.8A at 6V, so our DRV8835 Dual Motor Driver Kit for Raspberry Pi would not be appropriate. We typically recommend using a driver that has a continuous current rating greater than the stall current of your motor. Generally, you would use one motor channel for each side of the robot, wiring the motors on each side in parallel. You might consider something like a pair of our 18v7 Simple Motor Controllers, which can handle the current of two motors combined and should work well over TTL serial form a Raspberry Pi.
A 5V 1A regulator like the #2119 should generally be fine for the Raspberry Pi power, but you might need more current for your camera and WiFi model. I am not familiar with the camera or WiFi module, so you will need to find out the maximum current draw and add them together to see how much additional current you need. You could then get a regulator that can handle the total current of those components and the Raspberry Pi. I recommend connecting the Simple Motor Controllers directly to your battery pack. I would also suggest a larger battery pack with this setup, since the Simple Motor Controller’s minimum voltage is 5.5V (only 0.5V below your battery pack), so a higher voltage pack (like a 6 cell pack) will help you avoid a brownout if your motors draw a lot of current suddenly.
Hi Derrill, thank you for the answer. Regarding the voltage regulator for the Rpi everything it’s fine, and yes 1A it’s not enought for wifi and camera togheter.
Regarding the motor, i checked on the specification for the motor and are:
so if i have understand, if i connect 2 motor on the same channel we have 470mA x 2 = 940mA drain by 2 motor in stall on one channel, so i guess that the #2753 should be ok?
Regarding the battery pack, right now my battery holder support 5x AA battery, i have 5 AA 1.2V 2000mAh, if i check with the multimiter, there are 6.66V in output on the battery, is the voltage ok to power 4 motor?
As far as the batteries, the 6.66V you measured is at full charge, that voltage will drop fairly quickly (especially during larger current spikes), so I suspect you will still get better results from a 6-cell battery pack.
