Screen not starting up.

Technial Support / Discussion

Last Post by uugear 7 days ago

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Pilzner

(@pilzner)

Posts: 3

Active Member

Topic starter

I have a pi 5 and a witty pi 4 installed.
Voltage is 12v / 5 amp.

My touchscreen & Pi will not start when I power through the witty. Green light seems to be active on Pi and I get a quick blink on the screen. No issues when I remove the witty.

If I disconnect the screen, keeping the witty connected, the Pi boots up correctly and I can remote in.

Thoughts?

Posted : 27/11/2024 4:58 pm

uugear

(@admin)

Posts: 486

Member Admin

You didn't mention how your touchscreen connects to your Pi. If your touchscreen is taking current from your Pi, then that extra current will also increase the voltage drop on Witty Pi's MOSFET and effectly lower the actual voltage appllied to your Pi. This can be confirmed by measuring the actual voltage on the 5V pin in your Pi's GPIO header.

If your touchscreen is taking too much current, it is recommended to power it separately. It is also possible to implement a circuit to get it powered when your Pi is up: by letting the 5V pin in Raspberry Pi to drive a relay or MOSFET to power your touchscreen.

Posted : 28/11/2024 9:35 am