Hello,
I am trying to connect a Raspberry Pi Zero W with a Roomba Serie 700 through the Serial Interface. I use the supplied power in the mini-DIN without problems. But now I have added a small camera to the system and under certain circumstances (only when loading/booting Raspberry) the system requires more than 200 mA. According to the documentation, Pins 1 and 2 (Vpwr) are connected to the Roomba battery through a 200 mA PTC resettable fuse. The continuous draw from these two pins together should not exceed 200 mA. It will reset with 500 mA peaks. My question is: What can happen if I remove the fuse? Will it have other unexpected consequences? The second option is to connect the Raspberry directly to the Battery Pods. Of course, I am aware that the consumption of the Raspberry should be keep low when the Roomba is in the charging station (to allow battery charge).
Thank you in advance for your help!
Daniel
Hi,
We have not experimented what would happen if the fuse is removed, but we found that people attempting to connect a Raspberry Pi to the Roomba usually keep it in place.
We have found a nice blog for you to give you a rough ideas on how someone did it:
cfpm.org/~peter/connectingItUp.html
The guy used a DC-DC converter, to step-down the voltage from the battery and give enough amps to start up the Raspberry Pi.
According to your information, you should aim to have a step-down converter that could supply around 300mA.
You could use the following step-down converter:
5V, 300mA Step-Down Voltage Regulator D24V3F5
Thank you very much for your answer Mathieu.
I visited this blog, but as he was using a Raspberry 1 Model B (which consumes a lot more than the Zero) and included the use of batteries (and to say the true, documentation was a little bit scarce) I moved to other options…
I have built with a populu converter an small circuit that step downs the Vpwr obtained from the DIN connector. It is ranked to 600ma, the problem is the fuse 200mA limit.
From what I have seen in the Roomba PCB, the DIN Vpwr is connected to the fuse then to a diode and then directly to the battery… But if your recommendation is to connect directly to the Roomba Battery I think I will do it. It was easier in Series 5/6 (there was battery pods under the clean button), in Series 7 I think I will have to unmount almost totally the Roomba to access its PCB…
