4 ms·

I would love to see what tinkering could be done with low-power, minimal or "self-sufficient" location-placement of sensors to gather data and report data using

by platz 9y ago

I would love to see what tinkering could be done with low-power, minimal or "self-sufficient" location-placement of sensors to gather data and report data using Lora, cdma, or HF for long range. Why? Because electronics are small and there should be interesting ways to exploit the difference between this smallness and full blown CPUs operating on the grid. But I have a hard time generating good ideas. Any thoughts?

draugadrotten 9y ago
I'm with you. Using the Things Network https://www.thethingsnetwork.org/ https://www.thethingsnetwork.org/ I am currently setting up a gateway and connecting a few remote sensors to it. Right now I am just sending simple sensor data (button_press, temperature, light etc) but I would like to expand on this and send other data. For example I want to be able to deploy my own speed traps, measuring vehicle speeds on any road I want. I don't need to connect the speeds to reg plates, so I'm thinking about just measuring when the car passes through an IR beam or measuring a magnetic pulse or similar... Also, air quality monitoring. And of course, the robot lawn mower is getting an upgrade for the spring. Water temperature in the lake might be a good addition for summer. I forgot to say but since it is https://www.thethingsnetwork.org/ https://www.thethingsnetwork.org/ everything I do is already connected to Alexa and IFTTT... imagine waking up in the morning and having Alexa tell you that it is a good day for a morning swim, since the water is X degrees. Yum.
- platz 9y ago
  Those are fantastic ideas - love it!
simonbarker87 9y ago
Making extremely low power consumption nodes is very satisfying, I made a very simple light sensor remote sensor node that could power itself from 50mg of vibration acceleration a few years back on as part of my PhD in energy harvesting. The mast challenging part was getting the pic to draw the absolute minimal current and manage the power draw of all the other systems. The current draw was so low by the end that we had to use an electrometer with a 30 giga ohm (if I remember correctly) input impedance to accurately measure the current draw. Programming in asembly was a pain but I had a lot of help on that so not awful.
- asmithmd1 9y ago
  A high voltage meter input impedance will minimize the meter's effect on the circuit under test when measuring voltage, not current. For accurate current measurements, you want to measure the voltage drop across an accurate, low-value "shunt" resistor that carries all the current for your circuit.
  - simonbarker87 9y ago
    Correct, so we used a high impedance voltage meter across a calibrated resistor in series with the circuit under test. It was 7 years ago I did the work and now rarely work hands on with electronics so I am hazy on the exact details but it’s all in the published journal paper, which, as always with science papers is now behind a paywall. UPDATE: I miss remembered, we used the high impedance electrometer to buffer the input of a National Instruments interface board so we could record the voltage build up across the storage capacitors, if you use a normal voltmeter the caps just discarge into the voltmeter and the charge never builds up enough to allow the micro controller to turn on, run the code it needs to and then go back to sleep. You land up with some really nice sawtooth wave forms with this method and, as the acceleration on the vibrational energy harvester increases, the frequency of the sawtooth changes proportionally up to a point where the system is transmitting all the time.
jerrysievert 9y ago
take a look at the feather m0 from Adafruit - I have a few deployed where wifi is quite a ways away, gathering data for me and sending to another one acting as a base station. I haven't added solar, as these are inside, near power, but have some solar panels and hardware waiting for me to deploy out in the field (literally). so far, it's been my lack of good waterproof enclosures that has slowed me down. I wonder if there'd be a good opportunity for someone in that space.
- Kliment 9y ago
  Put it in one of those sealable jars with hinges - stuff a few packets of dessicant inside to stop condensation and you're done. If you need to pass through wires score a v-shape into the seal and make sure they get squeezed tight when you close the jar. Something like http://img4.foodservicewarehouse.com/Prd/1900SQ/AmericanMetalcraft_HMJ5.jpg http://img4.foodservicewarehouse.com/Prd/1900SQ/AmericanMeta... make sure to get some extra sealing rings if you do passthroughs as it's hard to get the scoring right.
- platz 9y ago
  But what did you use it for
- HeyLaughingBoy 9y ago
  What opportunity do you see? There's a huge variety of different flavors of water-resistant enclosures on the market, from things that can only take light spray, to underwater-rated enclosures. Google IP-66 or NEMA4 enclosures. Also, I have at least one project that was housed in clear 3" PVC pipe since it had to go down a well. One of my favorite companies to work with in this area is Polycase.
abraae 9y ago
I am working on a lora/arduino mesh network for reporting back the state of a large number of traps for invasive predators (mustelids, possums, rats). The traps are spread around the countryside in dense bush/jungle. When one goes off, someone needs to tramp in and clear and reset it. Currently, there is no monitoring of any kind, so checking traps is extremely labour intensive. The trickiest aspect of this project is that each node needs to spend virtually all of its time asleep to minimise battery drain, yet for two nodes in the mesh to communicate, they both need to be awake at the same time. Drifting clocks etc. The easiest aspect is that the acceptable data rate is 1 bit every 8 hours or so!
- icebraining 9y ago
  I'm totally ignorant about radio hardware, but I'm curious, why not use a chip with wake-on-radio?
  - abraae 9y ago
    Good idea, except that wake-on-radio requires the radio to be powered on all the time. Whereas I need to sleep everything except the arduino watchdog.
- vkuruthers 9y ago
  What a cool and useful sounding project! Does LORA handle any of the meshing aspect, or do you have to manage that at the application level? Also what kind of node to node range are you getting from the radios, and when the users install them, how do they know they'll be within range of the next node?
  - abraae 9y ago
    Yeah, it is some fun, wish I had more free time to devote to it. LORA doesn't handle any of the mesh behaviour, I'm doing all of that using LORA just at the send and receive level. The devices I am using are moteinos - a cool arduino lora mashup https://lowpowerlab.com/guide/moteino/ https://lowpowerlab.com/guide/moteino/. I see various ranges from LORA, the environment is steep valleys and dense bush which severely dials back the range, sometimes down to a few hundred meters or even less. At this stage I haven't played around with optimising the LORA settings, but there are bound to be some wins there since the required data rate is so low. Good question about installs, my current plan is that before setting out, the user places that part of the network where they are heading into constant beacon mode. The node can then be installed, knowing there's another node within reach. In practice this should be fine anyway, as the recommended placement for traps for e.g. stoats is every 100 meters or so, so usually there will be other traps within range.
sbr464 9y ago
Are you referring to using something like the particle.io platform?

by platz 9y ago

draugadrotten 9y ago

I'm with you. Using the Things Network https://www.thethingsnetwork.org/ https://www.thethingsnetwork.org/ I am currently setting up a gateway and connecting a few remote sensors to it. Right now I am just sending simple sensor data (button_press, temperature, light etc) but I would like to expand on this and send other data. For example I want to be able to deploy my own speed traps, measuring vehicle speeds on any road I want. I don't need to connect the speeds to reg plates, so I'm thinking about just measuring when the car passes through an IR beam or measuring a magnetic pulse or similar... Also, air quality monitoring. And of course, the robot lawn mower is getting an upgrade for the spring. Water temperature in the lake might be a good addition for summer. I forgot to say but since it is https://www.thethingsnetwork.org/ https://www.thethingsnetwork.org/ everything I do is already connected to Alexa and IFTTT... imagine waking up in the morning and having Alexa tell you that it is a good day for a morning swim, since the water is X degrees. Yum.

platz 9y ago
Those are fantastic ideas - love it!

simonbarker87 9y ago

Making extremely low power consumption nodes is very satisfying, I made a very simple light sensor remote sensor node that could power itself from 50mg of vibration acceleration a few years back on as part of my PhD in energy harvesting. The mast challenging part was getting the pic to draw the absolute minimal current and manage the power draw of all the other systems. The current draw was so low by the end that we had to use an electrometer with a 30 giga ohm (if I remember correctly) input impedance to accurately measure the current draw. Programming in asembly was a pain but I had a lot of help on that so not awful.

asmithmd1 9y ago
A high voltage meter input impedance will minimize the meter's effect on the circuit under test when measuring voltage, not current. For accurate current measurements, you want to measure the voltage drop across an accurate, low-value "shunt" resistor that carries all the current for your circuit.
- simonbarker87 9y ago
  Correct, so we used a high impedance voltage meter across a calibrated resistor in series with the circuit under test. It was 7 years ago I did the work and now rarely work hands on with electronics so I am hazy on the exact details but it’s all in the published journal paper, which, as always with science papers is now behind a paywall. UPDATE: I miss remembered, we used the high impedance electrometer to buffer the input of a National Instruments interface board so we could record the voltage build up across the storage capacitors, if you use a normal voltmeter the caps just discarge into the voltmeter and the charge never builds up enough to allow the micro controller to turn on, run the code it needs to and then go back to sleep. You land up with some really nice sawtooth wave forms with this method and, as the acceleration on the vibrational energy harvester increases, the frequency of the sawtooth changes proportionally up to a point where the system is transmitting all the time.

jerrysievert 9y ago

take a look at the feather m0 from Adafruit - I have a few deployed where wifi is quite a ways away, gathering data for me and sending to another one acting as a base station. I haven't added solar, as these are inside, near power, but have some solar panels and hardware waiting for me to deploy out in the field (literally). so far, it's been my lack of good waterproof enclosures that has slowed me down. I wonder if there'd be a good opportunity for someone in that space.

Kliment 9y ago
Put it in one of those sealable jars with hinges - stuff a few packets of dessicant inside to stop condensation and you're done. If you need to pass through wires score a v-shape into the seal and make sure they get squeezed tight when you close the jar. Something like http://img4.foodservicewarehouse.com/Prd/1900SQ/AmericanMetalcraft_HMJ5.jpg http://img4.foodservicewarehouse.com/Prd/1900SQ/AmericanMeta... make sure to get some extra sealing rings if you do passthroughs as it's hard to get the scoring right.
platz 9y ago
But what did you use it for
HeyLaughingBoy 9y ago
What opportunity do you see? There's a huge variety of different flavors of water-resistant enclosures on the market, from things that can only take light spray, to underwater-rated enclosures. Google IP-66 or NEMA4 enclosures. Also, I have at least one project that was housed in clear 3" PVC pipe since it had to go down a well. One of my favorite companies to work with in this area is Polycase.

abraae 9y ago

I am working on a lora/arduino mesh network for reporting back the state of a large number of traps for invasive predators (mustelids, possums, rats). The traps are spread around the countryside in dense bush/jungle. When one goes off, someone needs to tramp in and clear and reset it. Currently, there is no monitoring of any kind, so checking traps is extremely labour intensive. The trickiest aspect of this project is that each node needs to spend virtually all of its time asleep to minimise battery drain, yet for two nodes in the mesh to communicate, they both need to be awake at the same time. Drifting clocks etc. The easiest aspect is that the acceptable data rate is 1 bit every 8 hours or so!

icebraining 9y ago
I'm totally ignorant about radio hardware, but I'm curious, why not use a chip with wake-on-radio?
- abraae 9y ago
  Good idea, except that wake-on-radio requires the radio to be powered on all the time. Whereas I need to sleep everything except the arduino watchdog.
vkuruthers 9y ago
What a cool and useful sounding project! Does LORA handle any of the meshing aspect, or do you have to manage that at the application level? Also what kind of node to node range are you getting from the radios, and when the users install them, how do they know they'll be within range of the next node?
- abraae 9y ago
  Yeah, it is some fun, wish I had more free time to devote to it. LORA doesn't handle any of the mesh behaviour, I'm doing all of that using LORA just at the send and receive level. The devices I am using are moteinos - a cool arduino lora mashup https://lowpowerlab.com/guide/moteino/ https://lowpowerlab.com/guide/moteino/. I see various ranges from LORA, the environment is steep valleys and dense bush which severely dials back the range, sometimes down to a few hundred meters or even less. At this stage I haven't played around with optimising the LORA settings, but there are bound to be some wins there since the required data rate is so low. Good question about installs, my current plan is that before setting out, the user places that part of the network where they are heading into constant beacon mode. The node can then be installed, knowing there's another node within reach. In practice this should be fine anyway, as the recommended placement for traps for e.g. stoats is every 100 meters or so, so usually there will be other traps within range.

sbr464 9y ago

Are you referring to using something like the particle.io platform?