I'd like to improve on my current "garden sensor" (see: and now to something completely different.. | happy programming logbook : currently I am using 3v3 ProMini328 with a 9v rechargable battery - I am using various power saving "tricks" removed LEDs, sleep mode between measurements, etc - but I still need to manually recharge the battery after some weeks/months..)
But I guess some extra "regulator/recharge controller" would be needed and maybe a different type of battery should be used? Currently the cost of meterial for my old design is about 10$ per sensor - and I'd like to limit the amount of expensive/extra parts - since I'd not be able to use "many" sensors if those get too expensive..
Did anybody try something similar already? Suggestions?
Looks like an interesting project just that its cost is way too high for my liking. I quote the author: ".. Roughly speaking, the IOT Gateway ~$200, each of the Indoor Stations $50, and the Outdoor Station ~$175 including the solar radiation shield."
Still it may give me some ideas for the solar power stuff.. thanks for the pointer
I'd remove all voltage regulation and use sleep to the max to power the chip with 3 AAA batteries. I have some in my mailbox, they've been working flawlessly for nearly three years.
wothke:
Looks like an interesting project just that its cost is way too high for my liking.
I thought the costs were krazy high as well. many of the bits can be had for a fraction of the price.
I throw away a lot of microwave containers from frozen lunches, they would make a nice stacked weather enclosure.
Also, I have a tipping rain gauge that outputs a signal you can listen in on. that way, you can know when the last rain was and how much rain fell.
Bianco:
I'd remove all voltage regulation and use sleep to the max to power the chip with 3 AAA batteries. I have some in my mailbox, they've been working flawlessly for nearly three years.
wothke:
but I wonder how long those batteries would really last me.. (I guess your mailbox device might be awake less often..)
Absolutely, it's awake like 10 seconds per day to send RF messages. I don't know how much of a difference that would make. What's the power consumption of 23:59 of sleep compared to a minute awake for instance. My best guess would be that my batteries are loosing capacity just because time passes.
Also I am not a fan of throw-away batteries - even if they last for a year.. Still, thanks for the idea
In these applications the disposable batteries are the way to go. They are superior when it comes to long term low power supply: very little self-discharge, vs. rechargeables that lose their power every few months all by themselves. On the other hand, rechargeables are the way to go for high-power applications such as running motors. They're much better at supplying high currents.
The environmental cost of a single NiCd or NiMH battery is much higher than that of a single alkaline battery, and if you're using one alkaline for three years or more that'd be no more than three disposable batteries over the life span of a rechargeable one, where the rechargeable needs recharging every few weeks in the end due to losing capacity.
wvmarle:
In these applications the disposable batteries are the way to go. They are superior when it comes to long term low power supply: very little self-discharge, vs. rechargeables that lose their power every few months all by themselves. On the other hand, rechargeables are the way to go for high-power applications such as running motors. They're much better at supplying high currents.
The environmental cost of a single NiCd or NiMH battery is much higher than that of a single alkaline battery, and if you're using one alkaline for three years or more that'd be no more than three disposable batteries over the life span of a rechargeable one, where the rechargeable needs recharging every few weeks in the end due to losing capacity.
That's what I would think instinctively. Do you have studies on hand that back it up with numbers?
wothke:
LOL these are supposed to be small/cheap sensors so I would never dream of using an LA battery ..
If you really have the DIYer spirit, you'll build your own small lead-acid battery with 2/3 cells
Bianco:
If you really have the DIYer spirit, you'll build your own small lead-acid battery with 2/3 cells
I'll rather try the condensator based approach.. (I don't want to ever reopen the waterproof cases just to replace batteries.. - even if it was only once in a year..)
Bianco:
That's what I would think instinctively. Do you have studies on hand that back it up with numbers?
Not on hand, it's something I read a few years ago.
The leak current of rechargeable batteries I was all too familiar with, you just can't store rechargable batteries and a year later hope they still have power in them. No problem though with disposable ones, they have expiry dates of around a decade when you buy them - and likely can last a lot longer than that.
I'm currently using a version of the supercap-powered Arduino project as an outdoor sensor, and it works so well that you can get by with a solar panel about 1/10 the size of the one used in the article. The panel I use is 2 x Panasonic BP-242221 (each 24 mm x 22 mm), total 6 mA at 5 V in full sun.
Supercaps have an extremely low rate of self-discharge, don't leak, and unlike rechargeable batteries, don't fail to charge after many years of service.
wothke:
LOL these are supposed to be small/cheap sensors so I would never dream of using an LA battery ..
You can get rechargable hearing aid batteries, i think they are ni cad though.
EDIT
My grandad had a LA hearing aid although it was the shirt pocket type.
jremington:
Supercaps have an extremely low rate of self-discharge, don't leak, and unlike rechargeable batteries, don't fail to charge after many years of service.
