💬 MyMasterSensor
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@nca78 thank you, but will sensors like LM393 Light Sensor and DHT22 Module work with no problems bellow 3V? They are both rated between 3.3V and 5V.
Thank you
@soloam said in 💬 MyMasterSensor:
LM393
No not the light Sensor/DHT22 Module without some changes in them.
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@soloam said in 💬 MyMasterSensor:
LM393
No not the light Sensor/DHT22 Module without some changes in them.
@sundberg84 thank you
So basically to keep this modules, the only thing that I would have powered by the 3V is the radio and the atmega. I planned building the PCB without using the modules, but I have a lot of them laying around and I think that it would make the PCB more useful/easy to others that plan to use it.
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@sundberg84 thank you
So basically to keep this modules, the only thing that I would have powered by the 3V is the radio and the atmega. I planned building the PCB without using the modules, but I have a lot of them laying around and I think that it would make the PCB more useful/easy to others that plan to use it.
@soloam - The radio can go down to 1.9V (not clones) and the Atmega depends on if you want to change the fuse settings. Normal BOD is set a 2.8v but with internal oscillator you can go lower.
Its Easy to use modules only, but as you understand there are limitation. Its possble to power a 3.3v module from a Atmega328 pin if you power it @ 3.3v (D3 for example) if they do not need more than 40mA (MAX!). Then you can turn on and off the pin and save power. I have even made a testnode with a dc-dc step up which i sourced from D3 and could turn on/off to get 3.3v but its not pretty.
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@soloam - The radio can go down to 1.9V (not clones) and the Atmega depends on if you want to change the fuse settings. Normal BOD is set a 2.8v but with internal oscillator you can go lower.
Its Easy to use modules only, but as you understand there are limitation. Its possble to power a 3.3v module from a Atmega328 pin if you power it @ 3.3v (D3 for example) if they do not need more than 40mA (MAX!). Then you can turn on and off the pin and save power. I have even made a testnode with a dc-dc step up which i sourced from D3 and could turn on/off to get 3.3v but its not pretty.
@sundberg84 the idea is to sleep the node whenever possible, and when it wakes up (for example from triggering the PIR) it uses the wakeup to notify all the other nodes and go back to sleep again.
What you are telling is to use 2 Digital pins to one module? One to power it and other for the data? Is that it? I also thought about doing something like that, I would need to feed the atmega with 3AA (4.5v).
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@sundberg84 the idea is to sleep the node whenever possible, and when it wakes up (for example from triggering the PIR) it uses the wakeup to notify all the other nodes and go back to sleep again.
What you are telling is to use 2 Digital pins to one module? One to power it and other for the data? Is that it? I also thought about doing something like that, I would need to feed the atmega with 3AA (4.5v).
@soloam - whatever you feed into the Atmega will feed the modules then so you need a stable 3.3v or a regulator/step-up. for the modules.
Its not an easy task this. In my design I have "solved" this by using a DC-DC step up for everything except the Radio. Then I know everything uses 3.3v atleast. I then remove led and voltage regulator and during sleep Im around 50uA which is good enough for me.
The problem is the booster can introduce noice into the node and disturb the sensitive radio.
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@nca78 thank you, but will sensors like LM393 Light Sensor and DHT22 Module work with no problems bellow 3V? They are both rated between 3.3V and 5V.
Thank you
@soloam said in 💬 MyMasterSensor:
@nca78 thank you, but will sensors like LM393 Light Sensor and DHT22 Module work with no problems bellow 3V? They are both rated between 3.3V and 5V.
Thank you
The question is why do you want to use those ? :)
A small breakout board with si7021 is better than DHT22 in every way.
And for light there are also a few i2c sensors that are way better. -
@soloam said in 💬 MyMasterSensor:
@nca78 thank you, but will sensors like LM393 Light Sensor and DHT22 Module work with no problems bellow 3V? They are both rated between 3.3V and 5V.
Thank you
The question is why do you want to use those ? :)
A small breakout board with si7021 is better than DHT22 in every way.
And for light there are also a few i2c sensors that are way better.@nca78 - he had alof the them laying around... and its easy to use.
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Thank you @Nca78 @sundberg84 I think that I will redo my board to use a Temperature Sensor SI7021 and for light a foto resistance like the GM5539 (any opinion or alternatives?).
Better do it right, and I can use the sensors that I have around in tests or something.
One question, I'll use this inside a case, ok I can do holes, but will not this change the temperature and humidity readings?
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Thank you @Nca78 @sundberg84 I think that I will redo my board to use a Temperature Sensor SI7021 and for light a foto resistance like the GM5539 (any opinion or alternatives?).
Better do it right, and I can use the sensors that I have around in tests or something.
One question, I'll use this inside a case, ok I can do holes, but will not this change the temperature and humidity readings?
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