I have come across a few projects people have posted but they all seem to spec different components and I haven't managed to find something that is exactly what I'm after. I'll try to keep it simple (see attached image).
There are 4 beehives in this property that need to be monitored for humidity and temperature. The capacity to expand would be useful (maybe infrared camera, microphone?). The requirements are:
Battery Powered (last around 1 year, any longer is a bonus)
Wireless
Compact
Ability to log into the server remotely and monitor each hive
Ability to get the server to post updates for each hive to Twitter
I have a Raspberry Pi 3 Model B that I can use as a server for these four sensors. This can be placed in the garage (say 8 metres from the furthest beehive. Alternatively I have a Dell Server that could be used also.
Capacity to increase to say 8 beehives would be great.
All answers that will get me closer to this final product would be greatly appreciated. A parts list to start off with would be awesome, so I can at least order the items and start tinkering.
I'm in the real early stages of using things like Pi and Arduino and this is well above my understanding. I don't expect or ask anyone to spend considerable time designing this system, but if anyone has done a similar project I wouldn't mind their input on what is needed.
I'm sure there'll be someone who knows what they're doing that could easily list the components I need.
That's the thing - I can't tell what's suitable and what isn't. I am concerned I will cherry-pick items in the hope I can just put them all together to make this project and find that certain things are incompatible.
JazzyKeys:
Any pointers there would be appreciated.
Ask for advice, then spend your money wisely, rather than wasting your money and then asking for advice.
DHT22 are not great. They may not survive the winter before they fail, usually the humidity part.
Nano are a great first board for experimenting with Arduino. But they are not very low power for use in battery circuits. I don't think 1 year will be achievable with Nano unless you use a massive battery.
You will need some RF transmitters/receivers for the Nano to communicate with the Pi. Nano does not have that.
Arduino will be fine for temp & humidity sensors. But cameras and microphones are possible with only some special types of "Arduino", and these are not for beginners.
Is there WiFi coverage where all the hives will be located, even if the signal is weak?
How thick are the walls of the house/garage? Some types of RF signals are easily blocked.
Are the hives really only 8 metres from the house/garage? That does not sound like a good idea. You or visitors could be attacked for getting to close to the hives.
Thanks for the pointers. What would be a good alternative to the DHT22? They weren't too expensive but you're right, it can get costly. Is the BMP280 any good for this?
Also, what would consume less power than the nano and be suitable for this?
Shame about the microphone - that would have been really interesting.
I have a Ubiquiti UniFi and that has great coverage so WiFi is a possibility. Am I not right in thinking WiFi is quite power-thirsty compared to LoRa? Garage wall is single skin brick. House is timber and leaf, plasterboard inside.
Yes the hives are fine where they are. Neighbours on both sides fine. We cut the grass right up to it, bees not fussed about lawnmower or strimmer. On sunny days I often just walk around and take some close up photos - they're not a bother - you just need to know what you're doing Also you need to have a backup plan - ie somewhere to take them if things start heading south, which I do.
I have a few wireless temp/humidity sensors around the house, all communicating wirelessly using MQTT over WiFi. The sensors are on boards based on the ESP8266, mostly Wemos D1 Mini (programmed using the Arduino IDE). I use a Raspberry Pi3 running Node Red as the display.
The DHT's work well inside the house, but I've never used them outside.
The DHT22 spec is:
0-100% humidity readings with 2-5% accuracy
-40 to 80°C temperature readings ±0.5°C accuracy
So, I don't envision any problems outdoors as long as the DHT doesn't get wet.
Making the devices solar powered with battery backup is probably the only way to get the long battery life you want. I have a soil moisture device in my garden that is solar with one 18650 (3000 mAh) battery. The Wemos D1 Mini on this device wakes up once a minute and sends a reading to the Raspberry Pi. I will probably change this to once an hour because that is still more than sufficient for watering decisions.
I suppose your sensors will be in the hives, so sheltered from rain and frost. Maybe dht22 will survive...
For genuinely outdoor sensors I recommend those sht20/21/30 etc sensors that come in waterproof housing with proper cable glands etc. They are pretty cheap on ebay/ali express etc. Same for your circuit housing: use ones with rubber seals and plastic "screws", and use cable glands for the wires going in.
SteveMann:
I have a few wireless temp/humidity sensors around the house, all communicating wirelessly using MQTT over WiFi. The sensors are on boards based on the ESP8266, mostly Wemos D1 Mini (programmed using the Arduino IDE). I use a Raspberry Pi3 running Node Red as the display.
The DHT's work well inside the house, but I've never used them outside.
The DHT22 spec is:
0-100% humidity readings with 2-5% accuracy
-40 to 80°C temperature readings ±0.5°C accuracy
So, I don't envision any problems outdoors as long as the DHT doesn't get wet.
Making the devices solar powered with battery backup is probably the only way to get the long battery life you want. I have a soil moisture device in my garden that is solar with one 18650 (3000 mAh) battery. The Wemos D1 Mini on this device wakes up once a minute and sends a reading to the Raspberry Pi. I will probably change this to once an hour because that is still more than sufficient for watering decisions.
Thanks for that Steve, I think I have some rechargeable 18650's lying about - what was the configuration you used for battery housing and solar charging?
I could easily make do with long intervals between updates - a couple of hours? Once a day maybe.
I will have a look at the Wemos D1 mini. Thanks again!
PaulRB:
I suppose your sensors will be in the hives, so sheltered from rain and frost. Maybe dht22 will survive...
For genuinely outdoor sensors I recommend those sht20/21/30 etc sensors that come in waterproof housing with proper cable glands etc. They are pretty cheap on ebay/ali express etc. Same for your circuit housing: use ones with rubber seals and plastic "screws", and use cable glands for the wires going in.
I'll try the DHT's for now and once I have them set up and have learned a bit more I can tinker with making some with those sensors you recommend. Cheers Paul.
LoRa is great, I use it on more and more sensors these days. But there's a problem with this approach for beginners. It's a more complicated system. You need to build a transmitter circuit for every sensor node, and a receiver circuit, possibly connected to the pi.
By comparison, WiFi is, or can be, very easy. The pi can connect directly to your home WiFi signal. The sensors, if made with Wemos Mini or NodeMCU (esp8266) or esp32 boards, can also connect to the WiFi, all you have to do is connect the sensor and battery. It's true that the WiFi is not as low power, but with a quality 18650 battery, and sending readings a few times per hour, they should last many weeks to a few months between recharges. I guess you should be checking on the health of the colonies more often than that anyway.
I would consider using something other than LiPo for unattended outdoor projects. Yes plenty of people use them, but there are much “safer” options. LiFePO4, NiMH, etc.. LiPo charging is very sensitive to temperature if you’re using solar.
Also, I wouldn’t use the ESP32 for battery tasks. You can start off with it since it’s cheap, but if you’re sampling data frequently you’ll be replacing batteries fairly often.
Anyways, honestly outdoor battery operated project are anything but simple. You’re tackling hardware, software, power management, wireless communication, mechanical (enclosure), and backend all at once.
You can stitch stuff together to get started, but you have a lot to do.
czu001:
I would consider using something other than LiPo for unattended outdoor projects. Yes plenty of people use them, but there are much “safer” options. LiFePO4, NiMH, etc.. LiPo charging is very sensitive to temperature if you’re using solar.
Also, I wouldn’t use the ESP32 for battery tasks. You can start off with it since it’s cheap, but if you’re sampling data frequently you’ll be replacing batteries fairly often.
Anyways, honestly outdoor battery operated project are anything but simple. You’re tackling hardware, software, power management, wireless communication, mechanical (enclosure), and backend all at once.
You can stitch stuff together to get started, but you have a lot to do.
