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I’m trying to set up an OpenSprinklerPi system and since I’m nearly illiterate when it comes to configuration I’ve just been following the steps others have posted. I have set up a WiFi dongle and then I tried to set it to be a static port.
Everything worked perfectly when I had it connected to a monitor by HDMI. I was able to get on a laptop and go do the static ip I had set, able to set station schedules, everything.
When I disconnect rebooted without the HDMI display it seems the Pi refuses to connect to the home WiFi. If I have an ethernet wired connection then there are no problems.
I can connect with ethernet cable and no HDMI without issue. The only problem I have is when I try to connect using the wifi dongle and do not have an HDMI connection. Other forums have suggested that I needed to do the rpi-update which has been completed. Others suggested modifying /boot/config.txt to uncomment the line “hdmi_force_hotplug=1”. I have done both of these and am still unable to use the wifi without the hdmi connected.
Is there something I’m missing? Any suggestions would be very appreciated.
That’s seems odd and I’ve never heard of such an issue. The only thing I can think of would be a power-related issue. For example, if HDMI provides 5V to RPi, then that could explain the difference — once HDMI is removed, that 5V source is gone and hence the circuit is powered solely by the 24VAC to 5VDC converter on OSPi. If that happens to be insufficient, you will have a WiFi problem.
Most likely the issue is because your WiFi dongle is somewhat picky about the voltage. Although OSPi is rated to output 5V voltage, in practice the voltage may drop to 4.7V if the current draw is significant (this is due to the on-board PTC fuse, which progressively drops the voltage as the current draw increases). If the WiFi dongle is not tolerant to such voltage drop, it will perform poorly. There are several ways to address the situations, one is to change the WiFi dongle, the other is to bypass the PTC fuse to reduce the voltage drop.
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