Telemetry

Humnn, right. Let me understand something... what side needs to have the high antenna? The transmitter or the receiver? And if we are talking about the transmitter, how high? I'm thinking that could turn to be cumbersome racing a motorbike with a high antenna attached to it.

Is that possible to supply this amount of power from some kind of battery (regular alkaline battery, or even a cell phone battery) or from a 12v car/motorbike batery?

Now comes another question, do you know any product (basically a component) that uses this type of RF and is a digital data transmitter? Since I am a software engineer, this is not exactly my arena.

The perfect solution for me would be: mobile side=> an electronic component that could interface with my microprocessor, that would transform digital information into RF waves to be transmitter. If you know of any black box containing gps/RF transmitter with some GPIO ports, that would be even better. base station side=> an antenna and a receptor that would decode the RF signal back to digital information and send it to the host computer through USB. The provider of this solution would preferably supply a sdk or a dll to interact with the receiver and process the information real time.

Thanks

Padu

"Mark" wrote

I am aware of that, that's why I'm seeking help here. The plus on my project is the software side, so I was expecting to find something more or less already done in the hardware side. It is not my goal to start with a breadboard.

Padu

Hi Padu,

How about a cell phone with built in modem?

Nokia 3360, Motorola V66 or Motorola v70 to name a few.

Jay

"happyhobit" wrote

That looks like a good option. May be a little harder to market, since I'll have to sell a subscription bundled with my package. I saw some features of the phones you mentioned, and the motorola's look nice, since they connect using USB instead of infrared.

Oh well, I'll continue my research on available technologies... Have you heard of a ReFLEX wireless network? Looks like there is a electronic component that uses this network to send data across.

Padu

Hi Padu,

EarthLink has a vehicle tracking/monitoring system that uses the Motorola Reflex wireless network and includes a 12 channel GPS, a 32 bit processor, RS-232 port and discrete I/O.

Is this who you are planing to compete against?

Jay

"happyhobit" wrote

Yeah, kind of... I'm actively researching, and looks like Reflex network messages have a certain delay (1 or 2 seconds) that I think is acceptable for fleet tracking, but not a real time application like mine...

I saw some modules from National Semiconductors (LMX3888 series) that is a GSM/GPRS module. That would be very cool, but I think it will not resist my reality checks.

At 10Hz I assume you mean 10 reports of all data per second? I suggest you calculate your total data and baud rate. Radio is not a fast medium to put much data through without exceeding the legal bandwidth restrictions. If the baud rate ends up at 1200 or less you should have no problem with a 6KHz channel spacing or about 4KHz usable bandwidth. If there are no gov't regulations applying then no problem blasting wideband.

Look up the "Digital Angle". It belong to a company called Applied Digital Technologies.

Check out Amateur radio (ham) equipment for Packet and APRS operation. There is usually good local talent with the technology, and all of it is designed for 12V operation. Some manufacturers already include the digital interface in the transceiver, but not in the least expensive models.

The license is not really hard to get, and requires a test, but opens the higher frequencies that are designated "experimental" and raises the legal tranamitter power. You may be able to get a hardware collaborator if you visit a local club.

Kevin

"C What I Mean" wrote

Thank you by the hint. By the way, the name of the product is Digital Angel, and basically that's what I was looking for... but I'm afraid this technology will be of no use for me, since various racetracks here in the USA are not covered by a wireless network (at least for now), and it would be cumbersome to market the product, since you have to sell the product plus a subscription to the service....

I can't remember all the correct formulae but at 900 bytes per second

and standard modem techniques plus 10% packet overhead you are talking at least 10K baud !

I believe you have to have a minimum of 2.5 times the baud = 25KHz radio bandwidth.

Better check that one out if you are in a radio controlled country like US or Canada.

Most of our telemetry systems I work with use a compression technique (of a sort) called reporting by exeption. A predetermined tolerance is used to allow small changes to occur before transmitting the analogue values. A poll of all points is done every so often to insure synchronization of data ends.

Another technique we use sends one piece of "all the data" with every execption report, on a rotatary basis so that a complete "all data" report is actually being performed on a piece by piece basis over a couple of dozen reports. IOW analogue #5 = 123.45 analogue #9 = 543.21 status group#0 = 11010110 (last of exceptions) analogue #119 = 111.22 (no change, just its turn on the byte by byte complete)

time gap for master to poll again or another unit etc.. or radio rest (may not be 100% duty cycle)

analogue #5 = 123.99 analogue#3 = 186.22 (last of exceptions) analogue #120 = 1.69 (no change, just it's turn)

I doubt you will get a GPS to generate information that fast anyway.

see sci.geo.satellite-nav for more tech guys on GPS!

Ah.. yeah.. Angel..... bad spelling.. sorry.

Good luck with whatever you are doing!