I have a program on PC taking in string input from USB ( old program) I have a Android (4.X) tablet which needs to provide string input on USB to the program running on PC.
When I used the sample code on Android, following code gives empty hashmap. The PC( tried on 32 bit XP and 64 bit Windows 7) has Android driver.
mManager = (UsbManager)getSystemService(Context.USB_SERVICE);
HashMap<String, UsbDevice> devices = mManager.getDeviceList();
Any real working code example talking to PC over USB will help, pl. also point out if any driver etc. needed on Android to talk to PC.
I have tried both the Accessory mode and the host mode( just in case)
I'm not sure I exactly follow what you're doing here, but if I understand you correctly - it just won't work this way. The UsbManager.getDeviceList() is meant to be used with Android devices with USB host port, to which some USB devices are connected. But, as far as I understand, you connect Android tablet acting as a device to your PC acting as a host (I guess so, cause you wrote about driver installation).
If you want to communicate between Android USB device and some USB host (e.g. because your Android device has no USB host capabilities), you need to use accessory mode (I suggest you start with this Android Developers Blog post). But this mode requires special support on the USB host side (it must talk to the device with Android Open Accessory Protocol). Note, that getDeviceList() makes no sense in Accessory mode - first of all, connected accessory is a USB host, not a USB device, and there can be only one USB host on a USB bus.
If you want to communicate with PC using Accessory mode, you may want to try this AOAP implementation for PC. If all you need is to talk to Android device for some debugging needs, you may want to use ADB port forwarding and TCP connection instead.
Related
I want to build a device with sensors (either with an Arduino or a homemade circuit with a microcontroller) and I want to send data from it to an Android device via an USB cable. What is the library required to connect devices via USB? Is there any documentation I could read for it? The problem is that whenever I search for this I only get results about the ADK and their board, not for other devices.
Are there things I should know beforehand? I'm not new to either field, but it's my first project with the two connected.
Thank you.
The first thing to check is if your Android device is equipped with USB host interface. In such case you can connect a regular USB device to your Android and use this API to communicate with the device.
However, typical Android device (virtually every mobile phone) is only equipped with USB device interface, for connecting to PC or another USB host. In such case you have to use the Android's USB Accessory support. The most important idea behind Android Open Accessory protocol is that it swaps (logically) USB device and USB host roles. It's the USB host that looks for the device with particular vendor/product ID, selects particular USB protocol interface, and then simply uses the in/out bulk endpoints found to communicate - pretty smart, isn't it?
To build Android Open Accessory compatible device you then need a CPU with USB host interface. If you want to use Arduino, this shield is probably a good starting point, given its firmware implements Android Open Accessory Protocol already. There are some example applications as well.
This works great on my Nexus7 which is connected over the OTG to Arduino Mega.
Android USB host serial driver library for CDC, FTDI, Arduino and other devices.
Hope it helps!
You have two solution
1: Your Arduino board act as a USB host and power the Android device.
With this solution you have to implement and USB Host stack on your Arduino board and must implement Android Open Accessory Protocol. Your Arduino board must power the Android device. Then you app must use the USB Accessory API to communicate with your board.
Avantage:
work with almost all Android Devices (no need for an USB Host port on Android device)
Disavantage:
The device board is more complicated (must provide power for both devices)
Firmware is more complicated (must implement USB Accessory mode)
2. your Arduino board act as a USB device and the Android device powers
you board.
With this solution your do not have to implement a specific USB protocol. Your board will act as a standard USB device. Since you act as a device you can power your board directly from the USB cable (the Android device will power itself and your baord). To communicate with your board you will use the USB host API of Android.
Avantage:
the device board is very simple
the firmware is simple and easier to debug (you can even test it with you PC)
Disavantage:
Works only with Android devices that have an USB Host port
On most device you will need a specific cable or adapter (ex :otg usb host cable)
I have experience with solution 2, and it works pretty well. All source code for the Android source is available from the link below. I have verified that it works with sensor devices from the company where I work on the following Android devices:
Samsung Galaxy S3
Acer Iconia tab a200
Asus Tranformer Pad TF300T
But it should work on most tablets and recent phones you can see this post if you want look at our experience.
I want to develop on an unrooted android tablet that has both an OTG and Host USB. The Android Version is 2.3.0 so there are no Java api's to write directly to the USB host. The android device has to be attached to a computer using the OTG port so I need to connect the android host port to hardware I am designing (FTDI V2 in USB device mode). It seems the only way to communicate is using the adb to send commands from the Android tablet host port to my hardware slave port. My question is, is it possible to use the adb to communicate over the Android tablet host port, or will the adb only work on the Android tablets OTG USB port?
Any assistance appreciated....
David
You can connect to ADB on an Android device via WiFi. This would free up the OTG port.
See https://market.android.com/details?id=siir.es.adbWireless&hl=en
If u have a rooted device u can run the Linux binary with proper ownership, permission, and mode provisioning to the executable. Then you'd just hook up the OTG and use it as a client host. BE SURE ADBD IS RUNNING on server/target device.
You cannot use the OTG on the server side (target device) since the OTG represents the Host Control Interface and is specificly backwards to what you have set up...at least, that's the way it sounded.
In short, reverse the ports (if same type) to put OTG & HCI on the client side.
I found the USB docs for Android and from there it seems as if one could write a communication program on an Android phone that works exactly like on a PC.
I have a normal USB-cable that normally connects between a PC and an external device. On one end it is a normal USB on the other end it has a special plug for the device.
If I get an USB female-female adapter I could connect my normal Android phone cable USB end to my device USB cable and so basically plug in my special USB cable into the Android phone.
Does anyone have experience doing USB communcation programming on Android - basically copying normal PC USB functionality? All I would have to do is sent and receive text strings over the USB port - just like on a PC.
Is this possible or is the USB port programming on Android limited in any way
and not really identical to USB programming on a PC? eg. power supply through USB or anything else?
ps on the PC I need to have a FTDI driver installed to work with the external device.
Many thanks
UPDATE:
it seems that starting with Android 3.1 it is possible to do this - however, if I understand htis correctly, Android 3.1 runs only on tablet Android devices - I might be wrong with this - compared to Apple this all this pretty confusing (however, with Apple iPhone it will never work! ;)
Yes, Android supports USB host on 3.1 and newer, so you can connect USB devices directly to an Android device using a converter cable. Android 4.0 brings this feature to handset devices.
I have a general and quick question and since you can never get a hold of a developer at Google, I thought I would post the question here...
Can anyone tell me, if we want to use our phones to connect via USB to a missile launcher made by dream cheeky As suggested on the USB or ADK section of the developer's website, would we still need and Arduino board or a board that Google presented at Google I/O 2011?
I guess I am asking, in short, can we directly hook our phones to another device via USB, and compile a program via eclipse or with the ADK to have it run? or will we still need a board in between the phone and the device we want to connect USB...
Thanks in advance,
Richard
In ADK, the Android device acts as a USB Device and the Android accessory acts as a USB Host. When an Android accessory is attached to the Android device, the Android devices switches to "accessory mode (as described in ADK)". If your Android device has USB host already, still it will switch to accessory mode and acts as USB Device instead of USB Host. Actually, the motivation behind ADK is to make each Android device to work with any Android accessory. Accessory mode eliminates the need for USB host, since only few devices has USB host feature (It is costly).
So, if you want to work with ADK, you need an development card with USB host.
you do not need an ADK board if the device that you are connecting to your Android device is acting as the USB Device and your Android device is acting as the USB Host. This is the case with the Dream Cheeky USB missile launcher. You can connect a missile launcher directly to the device and control it. USB Host is only supported on Android 3.1 devices and later.
What would be the best way to access the USB as a serial port on an Android device (HTC Magic)?
I am thinking about an OBD-II interface. Can I do this on a standard phone or more likely will I need a modified firmware?
According to this post, Matt Porter presented a review of Android at the Embedded Linux Conference Europe. I mention this mostly because of the example used to describe the current state of Android.
"Just one more practical example: You cannot even plug a USB drive to an android system, since /dev/sd* is not an expected device name in their hardcoded hotplug management.
Executive summary: Android is a screwed, hard-coded, non-portable abomination."
I'm sure someone's working on it, but I'm afraid for now you're out of luck unless you're willing to go low-level and edit the OS.
PSFreedom (project to jailbrack Playstation 3) has list of controllers which support usb host mode which then translate to supported Android devices.
My own expirience is that usb host works on HTC Dream/G1 without problems.
For OBD-II I would suggest bluetooth ODB-II dongle which side-stepps problem with usb host adapter.
Depending on the USB chip in your particular phone, it may be possible to rebuild the kernel to support USB Host mode or USB On-The-Go (Host + Gadget modes) instead of the normal USB Gadget mode. I've found some people speculating that it could be possible on the HTC Dream. Assuming you could reconfigure the USB port in Host mode a USB to serial, ODB-II, or CAN should be doable.
From what I can tell Android is Linux of some sort, to have USB device which would apear as serial port, you should write a driver for that device. I don't know much about OBD-II interface but i am guesing they use some sort of USB driver for windows, same is for android, not mentioning the application to handle the driver.
I don't think the current Android devices can act as a USB host only as a USB device when attached to a host. So using the USB port as a serial port is not likely.
Get a hostmode kernel for your device and you can use python for android and the pyserial library to talk to the serial over USB. I did this with Huawei Ideos U8150 (here is the post) for a loopback test.