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I am currently using TS7250 board from "embeddedarm" for my sensor and having it set up at 30 KHz for data rate. However, the board is too big for my current application. Can anyone recommend another off the shelf product (size <3 inch^2) with date rate >= 2000 Hz?

Thanks a lot.

Kerith

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    \$\begingroup\$ Data rates are typically measured in bits per second (bps). Packet rates are typically measured in packets per second (pps), but can also be represented in Hz. When you say 2000 Hz, do you mean 2000 pps? If so, what packet size? What TX power requirements? What else can you tell us about your application? \$\endgroup\$
    – HikeOnPast
    Commented Nov 29, 2012 at 16:24
  • \$\begingroup\$ What is the desired radio range / Rf power please? Is your sensor output analog or digital? \$\endgroup\$
    – Anindo Ghosh
    Commented Nov 29, 2012 at 16:25
  • \$\begingroup\$ @ Anindo: radio range is < 5meter. sensor output is analog. \$\endgroup\$
    – Kerith512
    Commented Nov 29, 2012 at 16:39
  • \$\begingroup\$ @ DeanB: Their 12 bits ADC on board has 60000 sample/sec. For my application, I need a wireless system can transmit voltage signal for 2000 data per second. Yes, I meant 2000 pps. packet size is depending on the ADC. I guess 16 bytes/2 bits. \$\endgroup\$
    – Kerith512
    Commented Nov 29, 2012 at 16:54
  • \$\begingroup\$ I am no expert on digital electronics but some of our engineering teams frequently deploy ISM band matchbox-sized, coin cell driven, miniature remote sound sensor units which can handle real-time data aquisition and transmission of 4.2 kilo samples per second. I know they use a Texas Instruments IC that only released a year or so ago, and that the boards are sourced from China in small lots, 5 to 10 at a time. They scrapped the previously used embedded linux based devices about a year ago because they get much more performance from these new cheap products. I hope this helps in some way. \$\endgroup\$
    – Seemingly So
    Commented Nov 29, 2012 at 18:30

1 Answer 1

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For serial RF over a short range (< 5 meters mentioned by OP), you can find TI CC2500 based standalone low-cost, low power modules with an ADC built in, such as this one. A search on eBay and similar sites would find you other such modules based on this IC. The size is well below the specified dimension constraints.

The device essentially takes TTL and analog inputs and pushes them in serial data form through the wireless channel to configured receivers (again, the same module can be used) at speeds up to 38.4 kilobaud. Power consumption is extremely low, but so is the sophistication of the device: It is basic but gets the job done.

An alternative IC to search for, on which similar ADC + serial RF modules are based, is the nRF9E5 which has a built in 8051 microcontroller and ADC.

Another, popular option is an XBee or ZigBee module. These come in a variety of configurations, from basic serial packet radio through Bluetooth and WiFi. Here is one such option.

Search for "Xbee Direct IO" to find suitable modules. This YouTube video shows one such module in use.

All these options are smaller than the 3 square inch size constraint, and most do not require external antennas, they use a PCB trace as an antenna.

Do check the ADC specifications in each case for your specific purposes, though, as there is a wide range of options on that front.

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  • \$\begingroup\$ Thanks a lot, Anindo, I do have a ZigBee system from "waspmote". But it only achieve 100 Hz for data rate. I need a small multi-threaded wireless system. Do you have any ideas? \$\endgroup\$
    – Kerith512
    Commented Nov 29, 2012 at 17:02
  • \$\begingroup\$ @Kerith512 Multithreaded? If you mean multi-transceiver mesh or star, the CC2500 modules do that, definitely. Also, there are a wide variety of Xbee Direct IO devices: The 433 MHz ones should provide more than the desired data rates. \$\endgroup\$
    – Anindo Ghosh
    Commented Nov 29, 2012 at 17:09
  • \$\begingroup\$ I meant the operating system (i.e. TS-Linux for the TS 7250 board). Multi-threaded means it is capable of receiving new data while sending the piled data. If it is single threaded, it will miss many samples while the micro-controller is operating as "sending data". \$\endgroup\$
    – Kerith512
    Commented Nov 29, 2012 at 17:19
  • \$\begingroup\$ @Kerith512 I think you mean full duplex for the radio. Which is probably not required. Average data transmission times are so short that the probability of collision is so small to be not worth the added complexity. How much does the microcontroller need to send? \$\endgroup\$
    – Samuel
    Commented Nov 29, 2012 at 17:51
  • \$\begingroup\$ @Sanuel, need to send at least 2000 sample per second \$\endgroup\$
    – Kerith512
    Commented Nov 29, 2012 at 17:56

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