It seems like it requires 5 A while the batter pack only outputs 2 A (?). What would be the solution to this? Do I need to buy a whole new Pi board?
From memory, the capacity is 2000mAh, and maximum discharge is 5000mA. So, it should last about 24 minutes at a full 5A.
Interesting. The raspberry pi 5 is doing a “Low Power Reset” when I run any movement commands, I am guess that has to do with the output capacity of the battery pack or the hat that is included in the kit. Either that, or something is messed up in my configs.
Is the battery definitely fully charged? I.e overnight-ish.
Although if you say rpi5 needs 5A, then that doesn’t leave much for the robot.
Yep definitely fully charged. I can run the command to calibrate the legs, but as soon as any movement command is given it does a low power reset.
I switched to a Raspberry Pi 4 and I’m having no issues now. Might be worth mentioning somewhere there are a lot of compromises a person needs to make to have this working on a Pi 5.
My piCar / rPi5 / NVMe SSD has a similar problem, sometimes freezing when driving the first tests. I disabled (booting to) the graphic desktop, that helps for now.
And when powering the rPy itself with an adapter (yeah, not convenient for a car), even with desktop started, I have seen no problems yet.
As far as I know, Low Power Reset is triggered by a low VOLTAGE in the rPi, and the official power plugs have a slightly higher voltage (5.1 a 5.2V) then normal 5V adapters.
It might be that the voltage to the rPi drops a bit (0.2 volt) to much when the battery deliver more power the motors.
A solution might be a separate power circuit or separate battery powering the rPi only, isolating it from power fluctuations caused by motors.
Unfortunately a standard power pack won’t do because the ones I tried, deliver 5.0V and immediately gives Low Power Warnings in the rPi’s, even in the 3 and 4. So a 5A battery module with an adjustable 5V+ voltage is needed.
Are there schematics on the robot-hat power supply regarding the rPi power and the voltage?
The rPi5 is moderner and known to be more power-hungry.
Is there a program that logs the battery voltage and current?
Yes, the current draw of the spider robot is indeed relatively high. The current output of the current Robot Hat is 3A at a voltage of 5.24V. The voltage is not a problem; the main issue is that the current becomes too high when multiple servos move simultaneously. If the Pi5 is also connected to other devices, the current may become insufficient.
Currently, only the Robot Hat 5 used in the PiDog V2 product can output 5V at 5A.
Both the PiCrawler and PiCar-X products use the Robot Hat V4, which outputs 5V at 3A.
Please refer to the attached image for the power supply circuit diagram of the Robot Hat.
Thanks,
So replacing the battery pack with one having a bigger capacity won’t help. Neither could I find an easy way to provide 5.2V to the rPi power port using a separate battery module; the power pack 18650 modules I found had 5V, but were not adjustable to 5.2V, and need a seperate charging cable.
So I am switching over to a rPi4 now, using a 128 GB USB3 external SSD that fits between the chassis and the rPi. Need to reroute the robot-hat battery cables from the hole in the middle to the side of the chassis. And put an isolating sheet on low stand-off’s just under the rPi board preventing short circuit on the rPi’s electronics by the SSD’s metal case.
Only the USB plug is ugly sticking out of the back of the piCar; have to find, probably make, a short cable with an angled USB-A plug.
Can confirm this as well. Purchased the rpi5 for the picrawler. Individually servos are fine during calibration, but the rpi crashes immediately during move.py script. Replaced with an rpi 4 I had, and everything is fine now. Rpi5 should not be shown as an option for the picrawler until this is resolved. This was a Christmas gift as well, so very annoying!
Hi All. I think a workaround for this is to slow down the picrawler to reduce the possibility of a spike in current draw. For example if you’re running move.py, edit the Python code and change ‘speed = 80’ to ‘speed = 10’. Not ideal but it seems to work
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