Solar Powered Soil Moisture Sensor

[flopp]

@pettib
Did you remove the power from battery to Arduino when you tried to charge it again?
I tried to charge r battery for 1-2 days when I had arduino connected, didn't work. After I removed it and out the "lamp" in the sun for 5 hours I could connect the Arduino again and then I was on track again.

[pettib]

@flopp I think it´s was some bad connections. The new one is working very good.

[flopp]

@pettib
Nice

[doug]

@flopp

Hi I know its a bit off topic but what controller are you using to create the graph?

[AWI]

@doug Not my turn :blush: but the Graphs are std. Domoticz..

[punter9]

side thought

why not write your sleep setting as a variable on the arduino side that is dependent on battery voltage?

if v>(full charge) sleep x hours
if v>(half charge) sleep for y hours
if v<(close to terminal voltage) sleep for z hours/days

[flopp]

@punter9 said:

side thought

why not write your sleep setting as a variable on the arduino side that is dependent on battery voltage?

if v>(full charge) sleep x hours
if v>(half charge) sleep for y hours
if v<(close to terminal voltage) sleep for z hours/days
I don't see that it is needed. It will be no problem to send data every 30 min even when the sun is not shining. During a grey day I had vintage around 1.0-1.2.

The idea is useful if you think/know that the solar will not charge your battery

[punter9]

@flopp
sure is, It looks like this sketch already has already picked a set single point sleep time that achieved the discharge gradient being less than the charge gradient looking at the angles on the 7 day graph.

My question is why wouldn't you write an algorithm for your sleep setting so you don't have to mess with it if you get a cloudy week etc? You have variable charge gradients depending on weather so why not have a simple variable discharge gradient?

A simple one would be case A - sunny day discharge gradient B- very cloudy day discharge gradient C- emergency charge/top off battery

you could write an equation based off your existing data but honestly you probably wouldn't get much out of it past the simple set listed above that cover 99% of conditions you will see.

[flopp]

@punter9 said:

@flopp
sure is, It looks like this sketch already has already picked a set single point sleep time that achieved the discharge gradient being less than the charge gradient looking at the angles on the 7 day graph.

My question is why wouldn't you write an algorithm for your sleep setting so you don't have to mess with it if you get a cloudy week etc? You have variable charge gradients depending on weather so why not have a simple variable discharge gradient (or complex if you want to make an algorithm off the charted data) ?

At the moment I don't need it. But if I see that the battery gets drained to much, because of bad weather, I may be use your idea.

[punter9]

ha you are on it! caught me editing!

anyways I love your idea, I can guarantee I am looking for these little lights to be on sale every time I go out. This maxes out the clever scale.

[flopp]

The "lamp"(silver) that I run out of battery seems to be damaged, two days ago it stopped sending data, last reported voltage was 1.13V which is good enough to work.
Maybe the battery got damaged, it is a NiMh and I think they have some kind of memory?
But why doesn't it get damage when you use the lamp as a lamp?
Normally the lamp is charging the battery during the day and when it is dark it power on a LED which will lit until the battery is empty or maybe until the IC(YX8018) measure a low voltage.

Today I change my second "lamp"(black) to a 1.2v AAA NiMh2 800mAh. I think this will help to not getting to low voltage during night.
The battery that was included was mounted in the lid, I removed it and placed the new battery in the stick.
I also made the stick little bit shorter, but don't make it too short because then you will measure the moisture at the top of the soil.
The black round stick is 9 cm and the whole thing, when put togehter, is 28 cm from top(solar) to bottom(tip)

[flopp]

To have in mind

If you use the lamp with silver stick, it is metal, then remember to protect the battery if you but the battery in the stick.

Use hot glue at the top around the solar otherwise rain will stay between the solar and the place where it is mounted. I don't get water inside where the electronics are but you never know what will happen after a few month.

I have some problem with my black lamp it is rust on the positive connection, today it stopped working because if this, I had to remove the connection and put it back.
Recommend to solder the cable instead of using connectors, which I do

[Nca78]

First, thank you very much for making these tests, I found some similar garden lamps in a local store and thought they were cheap so I bought one to have a look. Seems they were not so cheap as I paid nearly 3$ despite living in a developing country :D
I will make a test with it as soon as I find a step up accepting the 1.xV of the battery, but I'm not sure if it will really work as the battery inside mine is a tiny V80h with a very limited 60mAh capacity, not sure if it will survive the sending of data...

@flopp said:

I have some problem with my black lamp it is rust on the positive connection, today it stopped working because if this, I had to remove the connection and put it back.
Recommend to solder the cable instead of using connectors, which I do!

I would put some hot glue there too, no ? When all connections are checked and the board is running fine you could even sink the whole electronic in hot glue to solve these problems "forever" ?

[flopp]

@Nca78 said:

First, thank you very much for making these tests, I found some similar garden lamps in a local store and thought they were cheap so I bought one to have a look. Seems they were not so cheap as I paid nearly 3$ despite living in a developing country :D

Thank you. $3 is not bad but expensive compared to mine :)

I will make a test with it as soon as I find a step up accepting the 1.xV of the battery, but I'm not sure if it will really work as the battery inside mine is a tiny V80h with a very limited 60mAh capacity, not sure if it will survive the sending of data...

This is what I use as step-up, search for that product you will find cheaper than $1.49
http://www.ebay.com/itm/DC-DC-0-8-3V-to-3-3V-Step-UP-Boost-Power-Board-Module-Converter-Voltage-RF-/282029936915?hash=item41aa4b5113:g:3GAAAOSw1DtXLS7Q

I would put some hot glue there too, no ? When all connections are checked and the board is running fine you could even sink the whole electronic in hot glue to solve these problems "forever" ?

Yes, why not, sounds like a good idea. But keep TX, RX, RESET and GND available to be able to update the sketch

[gbgent_nc]

@flopp you attached your sensors by two differant methods. Which methods seems to be working the best?

[flopp]

@gbgent_nc
The sensor itself is connected the same way, A4 and A5 on both. @gbgent_nc if you mean that one is glued, that is difficult to say if it makes any difference. I tried lamp1 and 2 in same soil but they always had ~10% difference, I also tried same sensor both glued in same soil still difference. You have to measure until the flower/vegetable is dry and check your percentage after this you can set an alarm on that percentage. E.g. I have spices with 30% when it is dry and a flower that right now is 20% and not dry, maybe different soil etc.
I recommend to glue the sensor on the arrow, otherwise it is very difficult to remove the lamp from soil, the sensor with stay in soil and you have to dig it out :)
I had a test with a cap connected to my voltage measurement A0, but it didn't make any difference. No need to use Cap.
I use other battery on one "lamp" only to be able to measure many days without sun.

Today I have 3 lamps, yesterday number 3 was put in the soil. I now measure every hour, before every 30 minutes.

[punter9]

I have a couple soil sensors running with simple bolts in the ground. No two sensors will read the same in the same soil, but that is because they are just a relative setup not an accurate setup. Doing what is recommended above is necessary. Determine what % correlates to watering time on the plants. Once this is done it is set and forget.

Also, on your batteries
"The phenomenon itself is very real. If a NiCd battery is repeatedly charged after it has only been partially discharged it will develop a lower voltage and a lower capacity. Fortunately, this effect is reversible by conditioning NiCds."

So I vote to help your poor cheap lamp batteries out by writing logic into your arduino that varies by battery voltage. You can write it in ranges

battery > X volts report every Y minutes
battery > Z volts report every P minutes
battery > .....etc

also to keep your battery in good shape you may consider every so many days ( 2 - 5 ) writing logic that says
every Q days report every 20 seconds (or another interval that will drain battery) until battery voltage = min
then
sleep until battery voltage = max

[PaweMed]

Hello. What should i do, when i have this problems:

czujnik:12: error: expected unqualified-id before 'default'

default BOD settings.

^

C:\Users\Kompek\Downloads\arduino-1.6.9\czujnik\czujnik.ino: In function 'void setup()':

czujnik:43: error: 'SENSOR_ANALOG_PINS' was not declared in this scope

for (int i = 0; i < N_ELEMENTS(SENSOR_ANALOG_PINS); i++) {

                              ^

C:\Users\Kompek\Downloads\arduino-1.6.9\czujnik\czujnik.ino:5:35: note: in definition of macro 'N_ELEMENTS'

#define N_ELEMENTS(array) (sizeof(array)/sizeof((array)[0]))

                               ^

C:\Users\Kompek\Downloads\arduino-1.6.9\czujnik\czujnik.ino: In function 'int readMoisture()':

czujnik:102: error: 'SENSOR_ANALOG_PINS' was not declared in this scope

pinMode(SENSOR_ANALOG_PINS[direction], INPUT_PULLUP); // Power on the sensor

       ^

exit status 1
expected unqualified-id before 'default'

[flopp]

I would have try to use Ardunio IDE 1.6.8

[Huczas]

it's misstaken source code - line 11 should be deleted and then all is compiling well, it's just end of comment from line 10, [enter] is unnecessery there.