Looking for long range signal transmission idea (wireless) - Page 1
Forum section: electronics / projects

author: chipwitch
author_rank: Frequent Contributor
timestamp: February 04, 2014, 07:03:18 pm
content: Wondering if maybe I've overlooked an obvious method. "Long Range" in this case is about 100m.Criteria:Low power consumption. Should last a month on a couple dry cells.wirelessSemi-private (ie. Line of sight)Compactportablenon-obtrusiveinexpensiveIR, laser and microwave are all that come to mind. IR lacks the range, laser runs the risk of inadvertently harming someone (?), microwave is just getting absurd. It's for a simple alarm sensor. Hard-wiring to the sensor the control isn't practical. Seems like a radio signal is my only option?

author: Legit-Design
author_rank: Frequent Contributor
timestamp: February 04, 2014, 07:13:00 pm
content: http://ronja.twibright.com/Power consumption as is might be an issue, but it can also be IR. You'd need to develop one yourself to suit your needs.What kind of data are you planning to send?433Mhz should have the best range. You don't need to use the watch, similar modules can be found on ebay.http://www.ti.com/tool/ez430-chronoshttp://www.ti.com/lit/an/swra169a/swra169a.pdfseparate wire antenna to replace that small PCB antenna and you should have no problem.Page 61http://www.ti.com/lit/ug/slau292f/slau292f.pdfTable 4-1. Estimated Battery Life (Demo Software)Wireless communications:Continuous SimpliciTI SYNC 0.9 mA 8 daysContinuous SimpliciTI ACC 3.7 mA 2 days

author: Marco
author_rank: Super Contributor
timestamp: February 04, 2014, 09:56:26 pm
content: Quote from: chipwitch on February 04, 2014, 07:03:18 pmEhh, doesn'tseemthat hard, I wonder if the cheap doppler radar modules you can get can be modulated as easily (use DROs instead of Gunn diodes, so maybe not).I'd just try what kind of signal you can get from a class 1 laser. The need to carefully aim at setup seems a bigger problem than safety.What kind of bandwidth do you need? If it only transmits when the sensor is triggered you could compensate for the range issues of IR with moar power.

author: daveatol
author_rank: Regular Contributor
timestamp: February 05, 2014, 12:42:50 am
content: Can't the nRF24L01 modules with external antenna make that distance? They are very low power as well. "Privacy" can be easily attained using a form of encryption.

author: scientist
author_rank: Frequent Contributor
timestamp: February 05, 2014, 09:32:38 am
content: Get something like this (http://www.ebay.com/itm/F03016-Dual-TTL-3DRobotics-3DR-Radio-Telemetry-Kit-915Mhz-for-APM-APM2-/251119585867), solder together a few high-gain antennas and you're good to go. Only issue is bandwidth, but this guy got around 4kbps over it with a few firmware hacks. (http://www.rcgroups.com/forums/showthread.php?t=2037213)

author: daveatol
author_rank: Regular Contributor
timestamp: February 05, 2014, 11:19:00 am
content: Some range test results for the nRF24L01 are available on this pagehttps://hallard.me/nrf24l01-real-life-range-test/Range for the pcb w/ whip antenna is apparently 150m+ with very good transfer results at 250kbps transmit rate (2 byte packets). These can be had on eBay for <$10

author: fcb
author_rank: Super Contributor
timestamp: February 05, 2014, 11:42:53 am
content: The OP needs to state the data-rate and preferably the duty-cycle (some bands don't allow for continuos transmission), also what the effect of errors will be (do they need a back-channel, is the data a one-shot deal, etc...)Without the data-rate it is pin-the-tail-on-the-donkey.

author: GeoffS
author_rank: Unknown
timestamp: February 05, 2014, 12:27:59 pm
content: I'm currently playing around with the HoperfRFM12Bwhich is supposed to have a 100 metre range.There's also theRFM69HWwhich is a higher power device and have been measured to over 350 metres.Cheap and readily available in 433, 868 and 915 MHz versions.

author: Psi
author_rank: Super Contributor
timestamp: February 05, 2014, 12:51:41 pm
content: Bluetooth serial port modules with some nice directional antennas will go 100M easy.And, being bluetooth, they're low power

author: komet
author_rank: Unknown
timestamp: February 05, 2014, 12:58:08 pm
content: I did a project with the TI CC430 last year (identical to CC1101 as far as RF is concerned). Using the reference circuit with PCB antenna I got 300m range reliably and up to 800m with errors. And the CC430, being derived from the MSP430, is very well suited for ultra low power.

author: hari
author_rank: Contributor
timestamp: February 05, 2014, 01:39:49 pm
content: Is this indoor or outdoor? Any country regulations to honour? Have a look at the EnOcean 315MHz modules. EnOcean is ultra low power (they have a lot of energy harvesting products that work without batteries) and the 315mhz variant should give you about 300m range in the open. The chips are quite smart and can do a lot on their own (simple sensors).

author: Kohanbash
author_rank: Regular Contributor
timestamp: February 05, 2014, 01:44:28 pm
content: Digi has a bunch of radios that might work for you.Depending how much battery capacity you have, you can have the radio go to sleep every so often to save power and get a longer battery life.http://www.digi.com/products/wireless-wired-embedded-solutions/zigbee-rf-modules/

author: nctnico
author_rank: Super Contributor
timestamp: February 05, 2014, 04:43:02 pm
content: Microwave is a good option. With a directional antenna (cheap to build) you can get Wifi over several km.

author: hagster
author_rank: Frequent Contributor
timestamp: February 06, 2014, 01:37:25 pm
content: I really like these.http://www.synapse-wireless.com/snap-components/rf-engineReally simple to program (wirelessly) via python and can control GPIO and UARTs.Long range - 1 mile (LOS)Low power consumption. Should last a month on a couple dry cells. uA sleep states.wireless - Zigbee based. Can form a mesh network if required.Semi-private (ie. Line of sight) - AES 128 encryptionCompact - Very small. Availiable with PCB antenna's or SMA connectors for external antennasportable - Yesnon-obtrusive - No flashing lights or buzzers.inexpensive - $17 to $40 depending on module.

author: clickinggreen
author_rank: Newbie
timestamp: April 01, 2014, 01:49:33 am
content: Quote from: GeoffS on February 05, 2014, 12:27:59 pm+1 for the RFM69HW modules, they work really well and have excellent range (+20db output power)!!!Personally I'm not so keen on the RFM12B modules, but I would also recommend the RFM22B modules (also HopeRF), but they cost a few more $ and probably aren't the way to go for newer designs (simply as a value thing)A quick google can get you some really good breakout boards for any of the HopeRF devices - these couple seem pretty goodModtronics RFM69HW Breakout board -http://modtronicsaustralia.com/shop/rfm69hw-breakout-board-with-module/EWS RFM22B -http://embeddedwirelesssolutions.com/rfm22b_915mhz_breakout_board

author: tautech
author_rank: Super Contributor
timestamp: April 01, 2014, 02:15:00 am
content: Have a look at what these guys have:http://www.rfremotech.com/SomeProducts.htmlhttp://stores.ebay.com/RFRemotech?_rdc=1I have tested their 433MHz 4 km transmitter to 10 km LOS !!!!!!

author: clickinggreen
author_rank: Newbie
timestamp: April 01, 2014, 02:28:12 am
content: Good range, but for most application the features and speed (those ones are pretty slow) of the HopeRF modules will be better for most users.By features I mean stuff like: automatic packet handling, TX & RX FIFO's, multiple modulation types (FSK, GFSK, MSK, GMSK & OOK) and much faster transfer speed (up to 300kbps). These features make your uC coding much simpler and more power efficent.It just depends what you are after.