Advice on sheep GPS beacon - Page 1
Forum section: electronics / projects

author: haurs
author_rank: Contributor
timestamp: April 24, 2016, 07:16:04 pm
content: Hi there,I've been playing around with this idea of having a GPS beacon on each of my sheep for easily locating them during their summer time in the mountains. We have the last years been testing out a GSM system for sending GPS positions via the mobile network (GSM / GPRS). Bue sadly due to weak/no mobile signal in many areas, the results hasn't been so good. In many instances the GPS positions doesn't get sent, and therefor the system isn't working as good.That's where the idea of a GPS beacon comes in, which I wonder might outperform the GSM system due to the lack of signal in these areas. The area is pretty flat, but got some small mountains here and there. The total distance / length of the area the sheep is grassing, is about 10km wide (6.2mi). The duration of the time grassing is about 3 months during summertime.I've been looking at some long distance beacons and it seems 10km is doable. But maybe that's in flat area with no obstacles (like trees small mountains etc).So what I'm trying to figure out here, is this doable, and can it be done for lower the price of the GSM system (which is about US$100 per unit).Having a powerful antenna to receive signals is probably doable, but carrying this seems a bit of a hassle (since it needs to be big I guess to receive any signals from ground).So to take this even further, what I also had in mind was the use of a drone to help me locate the sheep. I got a drone who can fly around an area of about 2-3 km, and what I thought could help is if the drone could be the one picking up the signals and coordinates from the GPS transmitters on the sheep nearby. We could then use the coordinates to locate the sheep faster and more easily.The idea behind the drone is to rise high up in the air and circle the area (as far as it can) - this giving it altitude and should also give very good signal strengt compared to standing on ground.Just to give a summary of this:- Track GPS position on each sheep (about 50 sheep in total).- Distance to sheep, up to 10km.- Position tracking should occur preferably when we wish to get the location.- The tracking duration should be about 3 months (maybe GPS position location each day, so 90 times in total over 3 months).I know this might be a lot, but hope it makes it clear of what I want to accomplish here.Hope somebody could give some guidance and recommendation on what they think would be best way to around this.

author: Cloud
author_rank: Regular Contributor
timestamp: April 24, 2016, 07:33:06 pm
content: I think the simplest solution would be a uBlox gps module (cca 15$ on ebay) and long range xBee modules

author: Jeroen3
author_rank: Super Contributor
timestamp: April 24, 2016, 07:50:08 pm
content: Maybe you can utilize LoraWAN? Or something similar, with possibly a satellite uplink located in strategic locations when there is no cellular to run a Particle Electron.https://www.sparkfun.com/products/13745https://www.particle.io/

author: Pjotr
author_rank: Frequent Contributor
timestamp: April 24, 2016, 08:00:12 pm
content: Although your sheep likely don't fly, I suggest to contact these guys:http://www.uva-bits.nl/

author: haurs
author_rank: Contributor
timestamp: April 24, 2016, 08:28:02 pm
content: Wow! Thanks a lot for the quick replies guys. All of the suggestions are totally new to me, but I must say theuBlox gps module + xBee, and alsoLoraWAN, RockBLOCK, Particleseems awesome.I need to get some more info around these 2 suggestions tho, so I can clearly understand what needs to be done in order to track about 50 units (sheep).Would be cool tho if the drone would track the units on ground while flying over - preferably in a good distance. Almost like a science fiction movie!So what I’m imagining is the drone being the mother, looking for all of her 50 children.So that would mean 1 receiver, and 50 transmitters.Would that be done best with the suggestion of uBlox gps module + xBee, or LoraWAN, RockBLOCK, Particle?PS. Thanks for the suggestion Pjotr, and I’ll check them out, but I would prefer building something on my own - I like a challenge and its fun to learn

author: amorgant
author_rank: Newbie
timestamp: April 24, 2016, 08:44:35 pm
content: Wow those RockBLOCK's look cool but I imagine cost wise that's impractical for 50 sheep. I would recommend a uBlox module too because they are easy to work with. However, while xbees's are nice, they can get a little pricey, I would recommend the NRF24L01+ with amplified antenna. They are so cheap and have excellent range!http://r.ebay.com/QWSK2KThen of course fly your drone over the area and detect all the nodes. Sounds like a fun project, I'm jealous!

author: tautech
author_rank: Super Contributor
timestamp: April 24, 2016, 09:00:13 pm
content: Garmin have a similar solution to what you require for hunting dogs.Each has a collar fitted with GPS and VHF to relay their whereabouts to the base station.Only does 12 dogs though.https://buy.garmin.com/en-US/US/on-the-trail/dog-tracking-training/astro-320/prod89564.html

author: Marco
author_rank: Super Contributor
timestamp: April 24, 2016, 09:13:20 pm
content: Quote from: haurs on April 24, 2016, 08:28:02 pmCosts for RockBLOCK seems a bit painful per sheep, other than that it's plug and play. Lora + GPS seems the most appropriate, ublox doesn't have a module for that yet. There are probably a ton of crowdfunding projects combining GPS and LoRa going right now though.I'd put a base station in a central/high location which runs off solar if necessary which relays to central control. Do all the tracking and drone control from there.

author: haurs
author_rank: Contributor
timestamp: April 25, 2016, 08:35:52 pm
content: Thanks again guys. This is very interesting and I’m learning a lot reading about different ways of dealing with this project.So RockBlock is sadly out of the picture due to price. BUT it would be nice if we could communicate with it using LoRa technology for example. Attach it to a drone, fly over and scan the area for LoRa devices, and let RockBlock do the job of reporting any units it found.Anyway, guess that can’t be done yet. And I can’t buy 50 RockBlock’s since it would blow the budget for thisNow the big question:Jeroen3 gave me a link to particle.io (nice project!), which seemed like a good match for this project. However after reading a bit more it seems this only offers WIFI and cellular, and specially WIFI won’t do much good for long distance tracking. But the products seems nice, and not too expensive as well (https://www.particle.io/prototype#photon)Anyway, so we’re down to LoRa or uBlox. Some recommend Lora, and some uBlox. But from what Marco said, uBlox is missing a module, so guess LoRa is the best pick. Correct me if I’m wrong here as I’m still trying to get most of the information around the different systems.With a solution based on Lora, what are we actually looking at when it comes to hardware?1. Base station attached to a drone for high altitude. Anything recommended?2. Lora module + GPS. Is there any good ongoing project related to this that could help?3. A way to read and plot the GPS coordinates onto a map.I think thats about it if I haven’t missed anything. This would be really cool to get going

author: Macbeth
author_rank: Super Contributor
timestamp: April 25, 2016, 09:00:47 pm
content: I've not looked into all the devices suggested, but I imagine the main problem is to do with battery power on the sheep when transmitting. I would have all the sheep ruminating about the mountain in ultra low power receive only mode - waiting for a trigger signal, perhaps a broadcast to all and/or a broadcast to individual sheep node. Low power GPS could be activated maybe once every hour or so to keep it ticking over and recording sheep-coords in each individual log.Only when you send your activation signal (broadcast or to individual) will the sheeps transmitter spring into life, live gps switched on, and high power transmission can happen, including battery life, GPS logs, and live data using packet radio.Maybe you need to register each sheep with a HAM radio handle to be able to broadcast high power on all those empty VHF/UHF frequencies legally?

author: kaz911
author_rank: Super Contributor
timestamp: April 25, 2016, 09:13:53 pm
content: you could look into TI sub 1 ghz power stuff. very long range with little power consumption. I think they have a 12 mile demo on YouTube. runs on 433 or 868 MHz and other licensed or license free bands - as far as I remember.http://www.ti.com/lsds/ti/wireless_connectivity/sub-1_ghz/overview.page

author: max_torque
author_rank: Super Contributor
timestamp: April 25, 2016, 09:43:50 pm
content: What about IR beacons on the sheep (collars or similar?) and an IR camera on the drone? Use a recognizable flash pattern (could use unique pattern per sheep). Make collars solar powered perhaps ? Would make the bits you need lots of cheap!

author: Marco
author_rank: Super Contributor
timestamp: April 25, 2016, 09:45:05 pm
content: Quote from: haurs on April 25, 2016, 08:35:52 pmuBlox is a brand for a variety of devices, not a communication protocol. They just presently don't have a module which combines GPS and LoRa.LoRaOnepresently on kickstarter uses an uBlox GPS module with LoRa though.Given the size of your plot I don't think using the drone as the receiver makes sense, LoRa should be able to cover the distance. Just make a receiver base station (with solar power if necessary) and relay the data from there (you can use a high gain antenna and/or more power there). You'll be able to get positions even when the drone isn't flying.

author: LaserSteve
author_rank: Super Contributor
timestamp: April 25, 2016, 11:32:09 pm
content: How about the classic stuff:http://www.com-spec.com/Look at the "asset tracking" products...Steve

author: Macbeth
author_rank: Super Contributor
timestamp: April 25, 2016, 11:42:55 pm
content: Is this Norwegian mountain private land, or do you let the sheep out onto public pasture? I imagine if it's public land then you will have difficulty erecting any comms towers...?Also, I am jealous that you have all this land available for you and your sheep. I am but a sheep of the UK government, locked in my city box capsule, milked for tax and punished for trying to escape...

author: nfmax
author_rank: Super Contributor
timestamp: April 26, 2016, 09:10:21 am
content: How about doing it the 'other way round'? Each sheep carries a transmitter, which wakes up periodically and transmits a bit pattern unique to the sheep. Say a short burst every 30 minutes or so, using one of the license-free bands like 433.92MHz. This can be done using off the shelf chips, with very long battery life (probably longer than the life of the sheep!). Then, at at least three suitable locations, with good LOS to the pastures, and good GSM coverage, install a fixed receiver with GPS and GSM modem. This listens for the electronic bleats from each sheep, and measures the time offset between the GPS 1PPS and a datum time in the transmission (e.g. a specific 1-0 transition that always occurs in each signal, sufficiently long after the start so that the receiver AGC has stabilised). Each receiver sends the sheep ID, 1PPS offset, GPS time, and its own location over GSM to a central system, which matches the multiple reports of each sheep and calculates the transmitter location by triangulation.Max

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 26, 2016, 09:19:50 am
content: Another approach may be to have receivers with an array of directional antennas, and compare the RSSI from each antenna so you could get a bearing and triangulate the position.You should be able to get sub-antenna position resolution by looking at the ratio of signal strengths between antennas.For an application like this you want to minimise the cost and power of the sheep-end part, so spending money at the fixed stations rather than the mobile ones makes the most sense.

author: haurs
author_rank: Contributor
timestamp: April 26, 2016, 12:35:26 pm
content: Great to see so many good feedbacks.The battery is something that needs to last for 3 months, so as user Macbeth talked about as well, the GPS (sheep node) would only need to send coordinated now and then. So active sleep mode would be needed for the battery to last I guess.Talking about broadcasting to individual nodes: wouldn’t it make this a lot more complicated since we’re then dealing with a 2 way communication? And how could we broadcast - making sure the broadcast is received?Btw. (Macbeth) this is not a private land. So no need to be jealousIt’s public mountain area, so it’s not free for me to do whatever I want. So I can’t mount any large antennas or anything. But that’s where the idea with the drone came in...The drone could easily fly 200 meter up in the air and hover over a large area in 15 minutes. And with a good system for receiving signals from all sheep nodes, it should be able to cover a much larger area than standing on ground with an antenna. Also worth noting: The area is not totally flat. Its a large mountain area with small mountains and hills here and there, thats why I thought getting up in the air would give signals a better shot of «calling home» to the receiver, which could be the drone.I sent an email to Texas Instruments who offers the TI sub 1 ghz (thanks kaz911 for recommending them), so we’ll see if thats something we could compare with. The range seems good tho, but I’m not sure about the size and the cost yet.max_torque: thanks for suggestion IR beacon. I found some youtube videos on that - mounted on drones. Seemed like a good way actually, but only thing I’m a bit worried about is the distance and how well it works in wooden areas.LoRaOne looks great Marco. So thanks for showing me this. Email already sent, so waiting for reply.nfmax: each sheep could carry a transmitter indeed, so that’s a new way of looking at this. But what do you think the overall cost would be per unit?

author: cgroen
author_rank: Unknown
timestamp: April 26, 2016, 01:20:39 pm
content: Haurs, have you tried to contact the company Telespor in Norway ?They already have a running system

author: FreddyVictor
author_rank: Regular Contributor
timestamp: April 26, 2016, 01:24:19 pm
content: to reduce power consumption, you could have the remote in sleep mode (ie no Tx/Rx), but then wake up and listen for commands at predetermined times for a short period of time (20s or less ?).and with a GPS onboard, you could keep the RTC correct

author: haurs
author_rank: Contributor
timestamp: April 26, 2016, 02:04:02 pm
content: Quote from: cgroen on April 26, 2016, 01:20:39 pmYes, that's a system we've tried, but didn't work that well in our area.But look at this a a fun project to make something great. Take the knowledge and build something that can even work in areas of bad mobile signals, maybe you even can make it cheaper than any of the other big companies out there (hopefully). But anyway, with this technology (LoRa etc), the possibilities seems quite big for a normal human being to make something on its own. Its fun and challenging at the same time

author: LaserSteve
author_rank: Super Contributor
timestamp: April 26, 2016, 02:04:26 pm
content: What I find amazing about this thread, is that if a 750 mW GPRS cell phone wont uplink, is that none of you have suggested working the Friis Equation to determine what WILL have a good link budget.Hint, its most likely low band VHF, or HF.Steve

author: haurs
author_rank: Contributor
timestamp: April 26, 2016, 02:10:03 pm
content: Quote from: wilfred on April 26, 2016, 01:44:58 pmMostly its finding them again after they've been grazing for 3 months. During past years we could spend up to 1 month locating them all (mostly due to the large area and the big movement of the sheep going back and forth without leaving much trace). But when that said, it would also be nice to be able to monitor them now and then if thats possible without too much complications.

author: Pjotr
author_rank: Frequent Contributor
timestamp: April 26, 2016, 02:15:58 pm
content: Quote from: LaserSteve on April 26, 2016, 02:04:26 pmBy itself that's right. However, it's not that simple, you will run into antenna problems (size vs efficiency). But I agree, there should be some optimum.About the power problem: What about solar charging a (Li-Ion) rechargeable cell?

author: CJay
author_rank: Super Contributor
timestamp: April 26, 2016, 02:33:31 pm
content: Quote from: LaserSteve on April 26, 2016, 02:04:26 pmMhmm, I was wondering about using something based around the PMR/FRS UHF bands, small antenna, cheap parts and a proven technology, I *think* it's legal to use data modes like packet on PMR446 and it'd be a simple thing to have them wake up, grab a GPS location packet, transmit for a few seconds and then sleep.

author: jitter
author_rank: Frequent Contributor
timestamp: April 26, 2016, 02:43:17 pm
content: Quote from: haurs on April 26, 2016, 02:10:03 pmI'm wondering... do the sheep move about that large area as a herd/group, or do they scatter?If it's the former, wouldn't you only need a couple of beacons rather than one per sheep?

author: Marco
author_rank: Super Contributor
timestamp: April 26, 2016, 02:46:41 pm
content: Quote from: haurs on April 26, 2016, 12:35:26 pmMaybe on the ublox that would be enough ... but a lot of GPS units have to be power gated to go low enough in power consumption.

author: nfmax
author_rank: Super Contributor
timestamp: April 26, 2016, 02:51:44 pm
content: And nobody has yet mentioned the difficulty of keeping the location devices attached to the sheep - though you probably don't have the thorn hedges and brambles we have round here. Sheep will spot and get through the most implausible-looking opening - it must be the only type of intelligence they posess. Great fun trying to chase them out of the garden when they do find a way in, though!

author: Marco
author_rank: Super Contributor
timestamp: April 26, 2016, 02:52:09 pm
content: Quote from: LaserSteve on April 26, 2016, 02:04:26 pmHe seems satisfied with just getting locations while being on the plot, and LoRA and similar ultra-narrowband devices can do that.If he does want to get data off the plot without being there, I'll suggest a base station for the third time. A simple high gain antenna towards the nearest cell phone tower should be enough to make a reliable connection. No HAM license required.

author: FreddyVictor
author_rank: Regular Contributor
timestamp: April 26, 2016, 03:04:52 pm
content: Quote from: nfmax on April 26, 2016, 02:51:44 pmmaybe some hints from thishttp://blog.particle.io/2016/04/01/cation/

author: haurs
author_rank: Contributor
timestamp: April 26, 2016, 03:32:33 pm
content: Quote from: jitter on April 26, 2016, 02:43:17 pmWell actually no. I don't think they like each other that much, so they tend to go solo with their newborn childrenSpreding across the whole area looking for the best area to graze.

author: haurs
author_rank: Contributor
timestamp: April 26, 2016, 04:15:53 pm
content: Quote from: CJay on April 26, 2016, 02:33:31 pmWell I was thinking this might get too complicated, but maybe I'm the one complicating things too much. I thought by just relaying on something like LoRa this wouldn't be too difficult to do - since its low in battery usage and should already covers most of the area by its range.Quote from: Marco on April 26, 2016, 02:52:09 pmLike I wrote above, I thought it would be too complicated, thats why I said to get data while being on the plot seems easier todo. However if you guys think otherwise, I'm open for this suggestion.Speaking of suggestions, when it comes to the high gain antenna, it might work, but I'm not sure it would work for the whole area - since its quote huge to cover by one antenna with mountains and valleys here and there. We've seen how difficult it can get for a mobile signal to pass though. It might work in one area, but then totally blank in another.In addition this is a public area, so I'm not allowed to setup a big antenna anywhere. So thats why I'm "hitting" the drone device so much, since it seems easier to just fly up scan the area and get the positions. Then move to the next area one at a time (I can't imagine we could cover the whole area by just one scan, thats why I'm dividing the whole area into several piece just to make sure we get them all).So to make this a bit more complicated, would it be possible to combine both these systems - get data off the plot without being there, but also use LoRa to scan the areas with bad signals?

author: haurs
author_rank: Contributor
timestamp: April 26, 2016, 04:21:40 pm
content: Quote from: nfmax on April 26, 2016, 02:51:44 pmSounds like you're speaking of experienceThey sure can be a hard to catch, but you should try goats!!Anyway, this will be the next thing to figur out. Has to be a good collar system with the tracker attached on top to get the best signals. Fun stuff!

author: electosleepy
author_rank: Contributor
timestamp: April 26, 2016, 04:49:12 pm
content: Is a GPS transmitter on all your sheep be the best solution? Would you be able to use a drone with a camera to find your sheep?

author: haurs
author_rank: Contributor
timestamp: April 26, 2016, 05:02:13 pm
content: Quote from: electosleepy on April 26, 2016, 04:49:12 pmSure, the drone got a camera as well, but covering the whole area would take too much time. Specially when the battery only lasts for 25-20 minutes of flight time. So therefor the sheep needs to "tell" where they are, so we could pickup the locations.

author: lincoln
author_rank: Regular Contributor
timestamp: April 26, 2016, 05:32:08 pm
content: If I may, Ublox make nice receivers but they are very proud of them. (expensive) A good option would be to some thing like a GMM-u2p form Gtop. The have other modules with the antenna included and run 20$ in low volume. We use them in a timing application where the customer doesn't want to pay for a premium timing receiver.

author: Koen
author_rank: Frequent Contributor
timestamp: April 26, 2016, 06:46:20 pm
content: We moved from GlobalTop to uBlox because once contacted by an uBlox salesperson, the price difference between both became negligible.Some companies on AliExpress like VKel offer uBlox (and others) compatible modules. Same footprint, same chip, same circuit, different discretes and around 10 USD per piece for a quantity of 1.

author: Spikee
author_rank: Frequent Contributor
timestamp: April 26, 2016, 07:17:17 pm
content: use cc1310 with the sensor controller and boost the rf output to 1W or so.Ultra low power, compact and does your job.I have recently made such device for a client which is 25x20x5mm with this chip, ladybird gps, chip antenna, dcdc , cc1310, uv light monitor , temperature and humidity monitor, eeprom , accelorometer. which is being used to track endangered animals. The energy consumption is very low because all the sensors / gps only get enabled if needed. Otherwise the power is just cut off. The energy consumption is very low because the device only sends once a day and is asleep the rest of the time / in RF receive interrupt mode. Without doing anything else than using the easiest power saving mode Task_sleep()For long range a decent wire antenna is needed with RF power amp / lna.Due to obvious reasons I can't show a pictureIf you trow away the chip antenna than the device can be as large as the gps (20x20x5 mm)

author: LaserSteve
author_rank: Super Contributor
timestamp: April 26, 2016, 07:58:33 pm
content: Sheep, Goats, almost easy....Try Cats!Seriously,If I knew I had enough battery, I'd be using a Packet style transponder with Slotted Aloha, ie timeslots... Each sheep can repeat the nearby sheep's location, acting as a repeater... At round-up time if interrogated. Otherwise I'd just use a simple tracker.Odds are you will need at least a watt, and a quarter or half wave antenna wrapped around the collar. Sheep are not very tall, so to get coverage, your receive or interrogator antenna needs to be high up.Do you have a friend with a private airplane? That would make life easy...Now for the bad news, wet, tall, grass adsorbs 2.4 Ghz...if you can go with VHF or UHF, there are tiny modules on Ebay that are the two watt core used in Baofeng radios, with select-able power output, a data input, audio input, and programmable frequency.. I'll see if I can find the Auction, they were 18$ a unit. They can reach the 173 Mhz that is used in some regions of Europe for data bursts, or UHF PMR frequencies. The downside is they are power hogs in receive.In most nations, you can have a watt at UHF, provided its a burst of no more then 7-15 seconds...Too baaaad this is so pricey:http://www.findmespot.com/en/index.php?cid=103Steve

author: Marco
author_rank: Super Contributor
timestamp: April 26, 2016, 08:03:57 pm
content: Quote from: LaserSteve on April 26, 2016, 07:58:33 pmWhat's the point of using stone age tech with that much power when ultra-narrow-band can have the same power/Hz? It's not like you need the bandwidth.

author: LaserSteve
author_rank: Super Contributor
timestamp: April 26, 2016, 08:07:46 pm
content: Stone age works when processing gain doesn't, due to lack of sync signals.Spread spectrum or Narrowband is great, but it has its downsides when all you have is battery for bursts.If the RX misses the Gold or Barker code, your screwed.Besides, with stone age, I can get a bearing very easily with a 2 antenna "phase switching " direction finder which costs 40$ to build, and/or a sound card on the laptop.I don't have much faith in GPS, I' tend to go with K.I.S.S...Of course this guy has done miracles with WSPR...http://qrp-labs.com/ultimate3/ve3kcl-balloons/ve3kcl-s9.htmlSteve

author: Back2Volts
author_rank: Unknown
timestamp: April 26, 2016, 10:37:46 pm
content: A couple of days ago I watched a nature TV documentary (NOVA ?) about the importance of connecting ways or paths between reserve parks, for the animals to move from park to park and keep the gene pool alive. For the studies they put collars on animals (bears, elefants...) with a system to report location just once per hour. Most of the time the device must be in suspend mode to extend the life of the collar to two years. Some bears were tracked from Canada over to the US for hundreds of miles and the elephants in Africa over many nations.I think they also do the same with the wolf reintroduction program in Yellowstone.What about getting in touch with one of these biology projects ?

author: haurs
author_rank: Contributor
timestamp: April 27, 2016, 07:41:35 am
content: Quote from: Back2Volts on April 26, 2016, 10:37:46 pmDo you happen to remember any names, or maybe I can find the documentary online? Might be worth looking up!

author: Fungus
author_rank: Super Contributor
timestamp: April 27, 2016, 08:00:32 am
content: Quote from: kaz911 on April 25, 2016, 09:13:53 pmCC1310: 114km range and a 20-year battery life.Impressive.

author: kaz911
author_rank: Super Contributor
timestamp: April 27, 2016, 09:47:53 am
content: Quote from: Fungus on April 27, 2016, 08:00:32 amyes - but line of sightbut still very impressive. the CC131x and CC26xx are rather cool devicesARM, Wireless and "ultra low power" input processor to determine if you want to wake up main processor or not. Neat and on my bench right now.....LoRaWan might be a great standard - but their business polices are "If you have money and donate $50k a year" you can vote and participate in the big things.... You can get doc's for free but everything else starts at $3k / year. I find these "extortion" scheme "standards" a pain in the backside.

author: Psi
author_rank: Super Contributor
timestamp: April 27, 2016, 10:16:53 am
content: Has anyone asked the sheep what they think?

author: Fungus
author_rank: Super Contributor
timestamp: April 27, 2016, 10:51:29 am
content: Quote from: Psi on April 27, 2016, 10:16:53 amI always thought sheep went around in groups.Mid you, three months is plenty of time for them to lose each other. They're not the smartest animals.

author: Back2Volts
author_rank: Unknown
timestamp: April 27, 2016, 04:07:58 pm
content: Quote from: haurs on April 27, 2016, 07:41:35 amNOVA "Wild ways" Episode 53:22http://www.pbs.org/show/nova/

author: mark03
author_rank: Frequent Contributor
timestamp: April 27, 2016, 08:16:25 pm
content: Quote from: kaz911 on April 27, 2016, 09:47:53 amCC131x look great and I hope to play with it eventually, but they are just as closed as the Lora stuff, only in a different way. With Lora the technology is mostly documented but you have to buy the magic hardware from a handful of approved suppliers, or go full SDR which isn't really practical for an IoT node. With CC131x you get nice performance on a variety of generic/vanilla modulation types, but you don't get low-level control of the radio (which might let a clever engineer *implement* Lora). They even dedicated a separate CM0 core to drive the radio, but it only runs TI-approved code---engineers not welcome. I suspect this is the radio analog of "GPU hell", which is to say, no one will disclose the low-level interfaces to their chips because doing so might give away some competitive IP

author: tautech
author_rank: Super Contributor
timestamp: April 27, 2016, 08:23:27 pm
content: Quote from: Fungus on April 27, 2016, 10:51:29 amThey often mob up to socialise but not so much when they've got young lambs at foot as the OP has mentioned.Given no restraints they'll spread for miles.(Sheep farming background as a kid)

author: haurs
author_rank: Contributor
timestamp: April 27, 2016, 08:36:28 pm
content: It seems we got a few different opinions on the CC131 vs Lora among the people here. I haven't used any of them, so I really can't tell who's better than the other, but if we look at for example LoraOne (https://www.kickstarter.com/projects/sodaq/loraone-the-lora-iot-development-board) you seem to get a lot your your buck at maybe $75. Throw in a good gateway and you should be good to go.Quote from: kaz911 on April 27, 2016, 09:47:53 amNow I'm not sure what all the talk about costing a lot, but maybe we're talking about different things / services (LoRa vs LoRaWeb)?

author: NivagSwerdna
author_rank: Super Contributor
timestamp: April 27, 2016, 08:48:56 pm
content: Receiving GPS is a power hungry occupation, and transmitting position even more so. I can see that having dots wandering around on a virtual map is quite appealing but it's not the only way to find your sheep. A radio transmitter that sends a very short pulse every now and again can be subsequently located using radio direction finding techniques.Just an idea.

author: haurs
author_rank: Contributor
timestamp: April 27, 2016, 09:00:48 pm
content: Quote from: NivagSwerdna on April 27, 2016, 08:48:56 pmYou're probably right. GPS is power hungry, but what other options are there other than carrying a huge antenna in your backpack? I'm not good at radio direction finding techniques, but if you can give some example how well this could work (with good distance) then I'm very much open to considering it.

author: Spikee
author_rank: Frequent Contributor
timestamp: April 27, 2016, 09:17:06 pm
content: Quote from: NivagSwerdna on April 27, 2016, 08:48:56 pmNot really as the gps is only on for 60 seconds or so until lock.Since the amount of data transmitted is limited the rf does not that up that much energy either. Since this is probably open ground, high elevation, the lock should be quick. -> detect that it is a bad place to get gps lock -> shut it off and try again in x time or if significant movement has been detected.Quote from: Spikee on April 27, 2016, 09:11:11 pmHow to save energy:1. Shut off any devices you do not need at the moment2. Send as little data as possible3. Use long sending intervals4. Shut off the mcu (or use one of the sleep modes) when it is doing nothing. Having a low power core also helpsHow to get good range:1. Use the RF frequency best suited for your application2. Good antenna3. Good sensitivity4. PowerAlso the CC1310 had and has quite some TI library issues that made the device kinda unusable for a lot of applications.After complaining for a month or two they finally fixed the major RF issues. Apparently I was the only one really doing something with the device at that time.The sensor controller documentation is shit, library documentation is pretty shit (functions that "exist" do not work for example, not clearly documented or shown in errata). Took quite some hours to figure it out.After spending way to many hours figuring out this shit it works now, biggest issues are fixed and it works pretty good now.The average current consumption is amazing.

author: LaserSteve
author_rank: Super Contributor
timestamp: April 27, 2016, 10:06:55 pm
content: For those who are curious, the attached picture is the basic classic method on VHF. Range would be around 300 meters with a good YAGI antenna at the receiver.Here is a chart from a commercial animal tracking outfit, battery size vs GPS logging rate, vs. useful time. This is just position logging, they get close to the animal using VHF tracking and download the GPS data from the logger. From ATS at ATSTRACK.com, typical GPS logging rates. They must have a phenomenal GPS receiver, in terms of current consumption.Battery Size:10 mAh 100 mAh 200 mAh1 second: 41 minutes 7 hours 14 hours1 minute: 36 hours 16 days 32 days1 Hour : 37 days 379 days 759 daysZebraNet serves as an interesting example.http://www.princeton.edu/~mrm/asplos-x_annot.pdfAt the power level the 1990s technology TREK radio consumes, they could do much, much, better on HF.I ran the topic thru the academic search engine at work, and came up with this:http://www.grazinganimalsproject.org.uk/stock_management.html?publication=1;101If a HF frequency could be allocated, I smell a market...Steve.

author: haurs
author_rank: Contributor
timestamp: April 28, 2016, 01:00:55 pm
content: Quote from: LaserSteve on April 27, 2016, 10:06:55 pmThanks for the the interesting read Steve. This is good old traditional trackingHowever the range of 300 meters is a bit too low in this project. The sheep is wearing bells as well, so we could hear them from around that distance also. But thats why I'm looking for a long range solution here, and thats also why I've been thinking about the TI or Lora, with the long range of up to 10km.

author: haurs
author_rank: Contributor
timestamp: April 28, 2016, 01:09:25 pm
content: It seems the preferred choice here is a long range system like TI or LoRa for example. But why don't we discuss the differences with these 2?What advantages does TI have over LoRa - and vise versa? (for example the kickstarter project LoRaOne:https://www.kickstarter.com/projects/sodaq/loraone-the-lora-iot-development-board)

author: Koen
author_rank: Frequent Contributor
timestamp: April 28, 2016, 01:43:12 pm
content: TI low power wireless chips use proven technology, are well known, are cheap, have an ecosystem of chips/baluns/devices designed by other manufacturers for it and are compatible with other manufacturers offering.LoRa is expensive, tied to a single manufacturer and heavily marketed with less than useful use cases. OMG so much range* !!*: 18 bits per second, 100mW, mast high, open field, no radio interference whatsoever, operator dancing on one leg, rainbow over the hills.On a more serious tone, check out openLora.com for real users experience. It's less glorious.

author: botcrusher
author_rank: Regular Contributor
timestamp: April 28, 2016, 01:47:09 pm
content: Perhaps you should use something similar to our helium filled bud over here. Getting WSPR data over the ocean!Balloon madnesstwo or three small pv panels could account for a collar rotating.Now, sheep don't float 10000km up, but your drone at a much lower level still allows for a large line of sight area.

author: LaserSteve
author_rank: Super Contributor
timestamp: April 28, 2016, 03:17:45 pm
content: Friis Calculation for CC1310 at 868 Mhz:Two dipoles at 2.1 dBi, 10 dBm TX power level, 10 Kilometers range: -97.0 dBm at the receiver. Ti claims -110 dBm RX sensitivity.Going to "boost mode" nets 4 dBM more at the RX, for -93 dBmFriis in this case is assuming perfect free space conditions of course. The TI sensitivity figure -110 dBm is a bench test with no thermal noise and perfect RF matching, and I note there is no noise figure spec for the front end in the data sheet, at least that I can find.Wiki claims the average height of an Adult Ewe to be 70 cm at the withers. Running a UHF line of site calculator I get 3 Km line of site for the Ewe in perfect terrain. With the Human holding the antenna on a stick at 3 meters, I get 10 Km LOS for the human in perfect terrain. If the receive antenna is on a portable tower, and was a gain antenna such as a YAGI, or stacked dipoles, you'd do much better. At 6 meters for the RX antenna height, you start to have a 10 kM receive bubble.I like to use a rule of 50% degradation at UHF/VHF in rough terrain, so a 1.5 kM range bubble for the sheep if the receiver is near ground. The limiting factor being the sheep's height.HF near field propagation starts looking really, really, good at this point. Unless you can build a tower for the receiver, or get the antenna onto a flying platform. Reducing frequency to 150 Mhz for example, results in a much better -65 dBM at the receiver.All of the above assumes very good VSWR match at both antennas.This also makes a strong point for development of a really good antenna pattern on the sheep's collar. Boosting Sheep TX power to a modest 23 dBM really would help with the signal to noise ratio at the receiver. Your operating in a region where antenna gain at the sheep does not buy you much increase in range, but where modest power increases help your bit error rate immensely. The modest power increase gives you a chance of some reflected paths aiding in rough terrain, but you do not want to increase TX power to the point you start getting severe multipath propagation.Friis calculator:https://www.pasternack.com/t-calculator-friis.aspxThe classical Java range calculator, which uses simplified equations worked out by two way radio companies in the 1960s...http://www.hamuniverse.com/lineofsightcalculator.htmlThere are more sophisticated freeware radio propagation programs out there that use actual terrain data, but the first order approximations here will hold if there are not tall rocks or severe vegetation.http://www.nautel.com/wp-content/uploads/2013/05/Radio-Coverage-Tool-NAB-2013.pdfThe ever so useful chart from MiniCircuits:http://www.minicircuits.com/pages/pdfs/dg03-110.pdfSteve

author: Marco
author_rank: Super Contributor
timestamp: April 28, 2016, 05:40:03 pm
content: Quote from: Koen on April 28, 2016, 01:43:12 pmJudging by the cost of the low cost modules available they can't be that expensive. Of course Semtech being the only supplier (I assume Microchip just packages their chip in a module) would be scary for a real product with long term support, but less relevant here.QuoteOkay,I did. What am I supposed to be seeing? I think I see excellent LOS range, lousy range with chip/PCB antennas and 1-2 km range in non LOS urban environments with good antennas. Not much differentwith TI.Quote from: LaserSteve on April 28, 2016, 03:17:45 pmShouldn't he be designing for 433 MHz? Europe and all ...

author: Koen
author_rank: Frequent Contributor
timestamp: April 28, 2016, 06:57:21 pm
content: Quote from: Marco on April 28, 2016, 05:40:03 pmOne Semtech transceiver needing an extra MCU is the same price as one TI transceiver+mcu combination and more than one Silabs transceiver + MCU combination. If he needs ready-made modules, there's plenty of cheap chinese modules. If he wants to build it himself, there's plenty of baluns to help him avoid RF traps.Quote from: Marco on April 28, 2016, 05:40:03 pmYeah that's my point, it isn't any more "Long Range" than the classic chips.

author: Koen
author_rank: Frequent Contributor
timestamp: April 28, 2016, 07:04:35 pm
content: Quote from: Marco on April 28, 2016, 05:40:03 pmThat would limit him to 10mW. 169 MHz would be best provided he can accommodate an efficient antenna on the sheep.

author: Macbeth
author_rank: Super Contributor
timestamp: April 28, 2016, 08:52:08 pm
content: Quote from: tautech on April 27, 2016, 08:23:27 pmI guess now you're no longer a kid you're just an old goat?...Ok, I'll get me coat...sheepskin at that...

author: tautech
author_rank: Super Contributor
timestamp: April 28, 2016, 09:10:46 pm
content: Quote from: Macbeth on April 28, 2016, 08:52:08 pmAt times a grumpy old goat too.Na, laughter is good and required each day.

author: Apollyon25_
author_rank: Regular Contributor
timestamp: April 28, 2016, 09:29:22 pm
content: We had a Lora point to point link running ~12km on 433MHz with small helical antenna on the device and a 1/4 wave on the main base station.

author: John Heath
author_rank: Frequent Contributor
timestamp: April 28, 2016, 11:57:53 pm
content: I have an out of the box idea for this. The biggest problem is cost per sheep. That means the sheep transmitter must be cheap. The one grand receiver can cost a few bucks but not the sheep transmitter. A crystal oscillator and ripple counter that produces a 1 minute pulse every 24 hours at precisely 12 midnight. That should be cheap at cost per sheep with CMOS gates , lithium battery and 1000 MCD LED. This should run for 3 or 4 months on cheap button type batteries. One minute per day lighting one LED for 1 minute a day is not a lot of power. All that is required at this point is a 100 dollar drone to fly over the land and take a picture from 1000 feet up at midnight. With even the cheapest crystal of 10 PPM the sheep crystals clocks should still be within 1 minute after 3 months for the 12 midnight 1 minute LED turn on. The LEDs can not flash all night long as predators would soon realize lit LED means free lunch. This way you will have a ball park idea where most of your sheep are to find them. One LED on your house plus another 100 feet away dead north will allow the drone picture to be superimposed on a map for sheep location within 10 feet or so.

author: botcrusher
author_rank: Regular Contributor
timestamp: April 30, 2016, 12:45:18 pm
content: I kinda like that.What about software that uses drone camera to search for white blobs?Sheep recognition could work...though, it relies on the drone to actually find them.

author: Fungus
author_rank: Super Contributor
timestamp: April 30, 2016, 01:07:40 pm
content: Quote from: John Heath on April 28, 2016, 11:57:53 pmQuestion: Does this actually have to run for three or four months?Can it just sleep for three months and then activate? That way you can use alotmore battery power for the transmitter because it only has to last a week or so. It could make the whole thing a lot cheaper and more effective.

author: Pjotr
author_rank: Frequent Contributor
timestamp: April 30, 2016, 01:42:50 pm
content: You have to do the math: 3 months = 100 days = 2400 hours. With a 5Ah battery you can draw app. 2 mA average. Transmitter power is less of a concern because it is used shortly and infrequent. Although you have to calculate its Ah budget. More of a concern is the GPS receiver. Most draw a lot more to keep position up to date. Although there are ones that only keep the map data and time up to date to do a warm/hot start for accurate tracking. Have seen GPS modules that draw only 0.5 mA average in that state.Also a link receiver substantial draws current in this case.. But you have very accurate GPS time on board, so a receiver isn't strictly necessary. Just use a defined time slot for each sheep to transmit its position. Although a 2-way link is much more reliable. But even then you can make use of time slots to scan each sheep.