Connect Nexus 7 tablet to Raspberry Pi Zero

Question

I have a Google Nexus 7 (2013) tablet running Android 5.1.1. I have installed ConnectBot and use it to connect to various networks via ssh.

I purchased a Raspberry Pi Zero and copied Raspbian Jessie (11/21/2015) to a micro SD card.

I have made a physical connection between the Pi Zero and the Nexus 7. I am using an OTG cable attached to the Nexus 7, into which is plugged a standard USB-to-micro cable attached to the USB connector on the Pi Zero. When I connect the cables the power light on the Pi Zero begins flashing, indicating that the connection is successful and the Nexus 7 is supplying power to the Pi Zero.

I would like to ssh into the Pi Zero from the Nexus 7 using a direct connection. I found these directions, but they don't work because my Nexus 7 does not have the tethering option on the wireless and network settings.

So how can a establish an ssh connection between the Pi Zero and the Nexus 7?

EDIT 1:

I got hostapd working. The wifi app on my Nexus 7 sees the Pi Zero and makes a connection.

But when I go to ConnectBot and try to ssh to the Pi Zero, I get a "Connection refused" error. Specifically, I ssh to pi@RaspberryPiZero and get back a message "Failed to connect to RaspberryPiZero/127.0.1.1 (port 22): connect failed ECONNREFUSED (Connection refused)" from ConnectBot.

How do I ssh from the Nexus 7 to the Pi Zero?

EDIT 2:

I got it. I was dumb. Instead of ssh to pi@RaspberryPiZero I did [email protected], which is the static address of the Pi Zero. All is working now.

Answer 1

There are two problems with your approach.

First, asking the tablet's boost converter to power the pi is a bit much - at the least it will give you short battery life, and there is a real chance of ultimately damaging it.

Next, putting the OTG adapter on the tablet end means the tablet will be the host and the pi the device. It seems that because the zero does not have a USB hub, it should be possible to operate it in a USB device mode, but as of the moment there doesn't seem to be much support for that (it is possible the introduction of the zero will give momentum to such efforts, but pursuing that path would just duplicate the existing model A / zero device mode questions).

If you want to do a direct USB-USB connection, you should probably turn things around, so that the pi is the host and the tablet is the device. Provide external power to the pi. Then use the USB OTG adapter on the pi end of the cable, and the normal USB cable on the Nexus end so that it's ID pin does not get grounded and it remains in device mode.

Once you have a pi-host to tablet-device connection you will have several options for establishing communication, however their details are Android questions which are more appropriate to the Android site than the pi one.

1. Use USB network tethering, possibly after installing a different build of Android which supports this (your Nexus was designed to be re-flashable)

2. Operate the tablet in USB Accessory mode, using software on the pi to be the host (rather than the original idea of something like an Arduino with a host shield)

3. Enable USB debugging on the tablet and use an ADB port forward for tablet-bound network connections. If you want pi-bound connections you can ssh in and enable a tunnel back through which you can forward them.

Another option would be to use a low voltage USB-serial adapter on the tablet and the UART pins on the pi, or else another USB-serial on the pi.