cvh17
Newbie level 1
I have two GSM/GPS modem HATs for Raspberry Pi.
HAT A is one of these: https://www.itead.cc/wireless/gsm-gprs-and-wifi/raspberry-pi-sim800-gsm-gprs-add-on-v2-0.html
HAT B is one of these: **broken link removed**
Using both a Pi model B+ and a Pi Zero, I can successfully power on HAT A at boot by the addition of these commands to /etc/rc.local (the operating system is Raspbian Lite, a Debian-based OS):
HAT B does not power on automatically with these commands, instead I have to turn it on using the power button on the HAT, which is going to be a problem as this unit will be out in the field, unattended.
I've found the schematic for HAT B here: https://www.waveshare.com/w/upload/2/20/GSM-GPRS-GNSS-HAT-Schematic_.pdf.
Looking at the section in the middle at the bottom of the schematic (titled 'RPI GPIO'), it would appear that the power gpio is number 17, and so the code I have in /etc/rc.local should work (but it doesn't) -- have I misunderstood the schematic and should I be referencing another gpio pin? Is it possible that this HAT cannot be switched on at boot by software? I don't know how to read the schematic, and I know nothing about PCBs, microelectronics or microcontrollers.
Can anyone suggest a way of getting HAT B to turn on automatically at boot, please?
HAT A is one of these: https://www.itead.cc/wireless/gsm-gprs-and-wifi/raspberry-pi-sim800-gsm-gprs-add-on-v2-0.html
HAT B is one of these: **broken link removed**
Using both a Pi model B+ and a Pi Zero, I can successfully power on HAT A at boot by the addition of these commands to /etc/rc.local (the operating system is Raspbian Lite, a Debian-based OS):
Code:
echo 17 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio17/direction
echo 1 > /sys/class/gpio/gpio17/valueHAT B does not power on automatically with these commands, instead I have to turn it on using the power button on the HAT, which is going to be a problem as this unit will be out in the field, unattended.
I've found the schematic for HAT B here: https://www.waveshare.com/w/upload/2/20/GSM-GPRS-GNSS-HAT-Schematic_.pdf.
Looking at the section in the middle at the bottom of the schematic (titled 'RPI GPIO'), it would appear that the power gpio is number 17, and so the code I have in /etc/rc.local should work (but it doesn't) -- have I misunderstood the schematic and should I be referencing another gpio pin? Is it possible that this HAT cannot be switched on at boot by software? I don't know how to read the schematic, and I know nothing about PCBs, microelectronics or microcontrollers.
Can anyone suggest a way of getting HAT B to turn on automatically at boot, please?