Let's Make Robots!

Using GPS via Serial Connection!

Well, I found out that Maplin had a really cheap GPS module that supports UART (Serial) at 38400 BPS. I'm still waiting for it, but here's what I have so far!

Here's the unit, and specs: (unit was JUST discontinued, so won't be able to find much info on the device itself)


There are thousands of fixed speed cameras in the UK and Europe. The GPS SpeedCam detector alerts you to over 5,000 camera locations in the UK and 22,000 throughout Europe. There’s even an opportunity to get free downloads for life.

  • Includes one year''s subscription to European safety camera database (internet access required)
  • Contains data on over 5,000 safety camera locations in the UK, and over 22,000 known locations throughout Europe
  • Simple warning beeps and lights to indicate safety camera locations
  • Covers red light safety cameras, Truvelo and Gatso cameras (mobile safety camera locations are not included)
  • Repeat annual subscriptions are only 9.95 per year for unlimited updates within the year
  • Report a new speed camera not on the database and you get a further 1 year''s free access to updates!*
  • Provide a detailed report on a new safety camera and gain lifetime free downloads!*
  • Product can also double up as a USB GPS receiver in conjunction with compatible mapping software (mapping software not supplied)
  • Includes synchronisation software, DC 12~24V car charger and USB cable for connection to a PC

 It uses an Annual subscription for the "SCDB" (Safety Camera Data Base) if you want to have it beep everytime you pass a speed camera.. and what not in the UK! Well, I'm not from the UK, and I'm a "1337" hacker, so I want to use this bad boy for some projects!


I've included the video that got me so excited! (thanks alot to Mike Mc at http://earthshinedesign.co.uk  for this video!)



I plan on using the TinyGPS library from Mikal Hart (found here! http://arduiniana.org/libraries/tinygps/)



Now, I ask my fellow LMR members for some help!

Inside, there is a 16 MB EEPROM, and an Atmega16. The GPS module handles the USB and UART connections on board, without external components..

So I'm curious to see if I'm able to "set way-points" using the Serial connection.  For example:

(Arduino code, not familiar with Basic or anything else, this just prints the word "$set_waypoint" to the serial connection)


And hopefully, have it save the area it's in currently to the EEPROM on board. And well, hopefully be able to read them later!!



I'm assuming that the EEPROM on-board is used for saving the data you download from your computer (for the safety camera posistions, and the speed limitations) just hoping to take advantage of that with my project! (Without having to use the computer)

I haven't received my board yet, so I'm not sure which GPS module is inside, but I'm guessing this module (it's the only 66 channel from Global Top, that isn't new):


It includes the datasheet, just didn't see much information on the UART connection.

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Having read the spec for the GPS receiver. I think the manufacturer has done quite a lot for us, but at the same time, not quite enough...

The device is sold as a fixed speed camera detector. You give it a file (you have to register at www.scdb.info at a cost of 9.95 Euro / year) which contains a lot of speed camera positions. You do get a voucher for a 1 year subscription to SCDB. (It's possible, but unlikely that at the price the box is sold as a loss-leader, possibly with the manufacturer making some cash out of the sales of the data.) It has 2 buttons, a speaker and a volume control. It's programmed to give visible and audible indication when you're exceeding the speed limit in the vicinity of a fixed speed camera. The buttons are for power and mute.

As an Advanced Driver, I have no interest in the device in this configuration, but the manufacturer HAS supplied us with TTL-level breakout points on the PCB. This means you can hook it directly to a Microchip PIC (with no requirement for a USB interface or a MAX-232 level shifter. (No, that doesn't mean my subscription key is up for grabs: I wouln't want to be seen to encourage you to break the law!)

The way I see it you have an ATMEL, an EEPROM and  GPS receiver. I'm not sure at what point the asynchronous comms has been tapped off for us: it might be between the GPS and the USB, but (looking a the spec for the actual GPS module) I think it's more likely to be a feature of the module which the safety camera advisor application doesn't require.

It's reasonably clear to me that the ATMEL sits between the GPS and the EEPROM. BUT it also looks like he USB goes directly to the GPS (NOT the ATMEL). This begs two questions: do the Points of Interest (POIs - Speed Camera locations in this case) go directly into the GPS or do they go into the EEPROM. If they don't go into the EEPROM, what is it for.

I have taken mine apart already and the nice people who made the device have also supplied a 3-wire interface on the board in a similar fashion to that of the asynch connection. I believe this is for the ATMEL equivalent to the Microchip PIC's ICSP. Ideally, I would reprogram the ATMEL to make the device a data logger rather than a waypoint detector. Sadly, it looks like a 3 (or maybe even 5) layer PCB. There's not  chance in hell I could figure out which pins do what. I would also guess that the manufacturer has locked the processor so it won't allow us to download the code.

The other recognisable component (apart from the four LEDS) is a button cell battery. this might be to help the receiver make "warm starts".

As you point out in an email to me, the COCOM may not be correclty supported. Frankly, I'm not that bothered. It seems unlikely that my robot will ever do 1000 knots, or reach an altitude of 60,00ft.

When you attach it to a PC USB port, it installs itself as a virtual serial port and starts spewing out NMEA sentences, which are text, so you can read them in SmartTerm immediately (like any GPS mouse).

For £15 it's a bargain. There were three of these units in two Maplin stores on Monday afternoon. I bought two of them and a colleague of mine has reserved the third, so good luck if you're trying to get them at this price in Northern Ireland!

I'm reliably getting fixes to 1.5m accuracy - indoors! I'm very happy and very excited about this little box!

For info, a superb guide to decoding the data from you GPS receiver can be found here.

Here's another photo of the board, arguably better than the one on the video. I'm afraid it's been LMR-scaled, but if you click it you can download a higher-res version. The screen print is very very informative. All the test points are labelled.




 I have this holux bluetooth gps :


This have a mini usb port but only for battery charging...

 And i´m thinking how to use it with my arduino 2009... someone have any info or idea?


Need to see the inside of it!