What product would I choose for this USB to Serial app?

Archive New Product Ideas
1

I have a device that outputs NMEA @115K baud via a USB. I want to convert that to SERIAL.

I want to be clear because so many times I have been misunderstood…

This is a GPS that does not use a display and outputs only via USB. I have another device that is not a PC that only reads in SERIAL RS232 (DB9).

I do not have a clear understanding of the control or the power source.

You guys would make my day if you could point me in the right direction to translate this NMEA data to SERIAL. The Baud is not too important.

What do I need to do?

Thanks in advance for your help!

2

You probably need USB host mode for that device. SFE has a module with a Vinculum chip that should work with it.

Leon

3

Unless your are locked into using that GPS device, it would be must easier in the long run if you just chose a serial GPS unit.

4

Agreed. It would be cheaper and much easier.

5

With in reason cost is not a big factor.

The GPS is multi-use device and it’s least intelligent action is the NMEA sentences. It has a very large database that is designed to assist the user at certain coordinates

The other device that is is plugging into will only except NMEA data via a serial interface. For this device the least intelligent thing it does is reads this data.

BUT what it does with this data is fantastic. I totally change the operation of the device based on where in the world it exists.

So I really, really need the device that you are speaking of and I will be looking on the site to see if I can find it.

Could you guys point me in the right direction?

Thanks big time for your responses.

Once I have it working I will share the 2 devices and the application on the site

6

STiMULi:
I have a device that outputs NMEA @115K baud via a USB. I want to convert that to SERIAL.

Thanks in advance for your help!

You have provided very little information really; why are you unwilling to name the device?

I would be surprised if the NMEA data is not serial at some point within the device then converted to USB again within the device. Can it be opened, investigated & photographed. It may be possible to intercept the data before conversion to USB if that conversion does indeed take place.

Regards

Dez Ellis

7

You need a USB HOST, as the GPS is a usb endpoint device.

You could use this, USBwiz

http://www.ghielectronics.com/product/3

$48 US

8

The USB device was this:

http://www.youtube.com/watch?v=-NVH3atDxlU

motopic:
You need a USB HOST, as the GPS is a usb endpoint device.

You could use this, USBwiz

http://www.ghielectronics.com/product/3

$48 US

What will I need to do to make the USB input become the SERIAL output?

I do not fully understand the device except to say that I see it is chiefly designed to move files from a USB/SD

Thanks!

9

STiMULi:
The USB device was this:

http://www.youtube.com/watch?v=-NVH3atDxlU

The video shows the connection to the device using Com14, therefore, the device contains a serial to usb conversion device.

Therefore, within the device before connecting to this serial to usb conversion device the signal is from some sort of uart type connection.

It will be probably be logic level signals from the UART and not RS232 voltage levels. However, depending on your electronics expertise and willingness to hack the device it may be possible to add a tiny breakout pcb with a RS232 level convertor similar to http://www.sparkfun.com/commerce/produc … cts_id=133 which will give you the RS232 connection that you require.

Re-routing the logic level uart signal to the RS232 level convertor will remove the existing communication method but you could perhaps add a changeover switch to select the destination of the uart signals RS232 level conversion or existing USB conversion device.

I am not aware of any “off the shelf” free standing device to convert the USB output back to serial or RS232. USB to RS232 convertors allow your RS232 device connect to a PC only.

10

just to make a point, some of the devices coming out in the market now a days have a USB like ocnnector, but the data coming from it is UART . They provide a special USB cable to use, this cable has built in UART-USB converters. I have encountered some of these devices, ex, mobile phone USB cables used to do this a lot and Sanav GPS systems use the same thing.

So it would be nice to see exaclty what the data looks like on the USB connector

11

There is no easy or inexpensive way to do this. The closest thing would be something with an “USB on the go” interface which can act as a host, or something like a beagleboard. A nokia internet tablet like the n810 would work (I have one so I know), but isn’t cheap.

There are some newer AVR or other chips which are inexpensive and can do USB host, but there would be a lot of code and setup.

Internally it appears it has a serial-to-usb, and you would just need to find the uart output and break it out separately.

The USBwiz http://www.ghielectronics.com/product/3 appears only to do bulk memory, not serial.

12

The device is a gps based traffic alert device, like a radar detectory, but for things like red light cameras (I’m developing something similar).

http://www.speedcheetah.com/

It would be easier/better/etc. to just get a second GPS. Semsons.com has bluetooth versions for about $20, there are modules here.

There is no easy or inexpensive way to do a USB bridge. The closest thing would be something with an “USB on the go” interface which can act as a host, or something like a beagleboard. A nokia internet tablet like the n810 would work (I have one so I know), but isn’t cheap.

Note that I use my internet tablet with one of the 10Hz venus modules here (or a wintec at 10Hz) via bluetooth even though the Nokia has GPS - but it is at 1hz and not as sensitive. The wintec also works over USB, but I normally use bluetooth.

There are some newer AVR or other chips which are inexpensive and can do USB host, but there would be a lot of code and setup.

Internally it appears it has a serial-to-usb, and you would just need to find the uart output and break it out separately.

The USBwiz http://www.ghielectronics.com/product/3 appears only to do bulk memory, not serial.