NRF24L01+ range of only few meters
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@LastSamurai also keep in mind that if you are using the LM2596 buck converter that you need to use a post ripple filter.
I explained that here: http://blog.blackoise.de/2016/03/building-a-lc-filter-for-your-nrf24l01-palna-module/. -
@LastSamurai also keep in mind that if you are using the LM2596 buck converter that you need to use a post ripple filter.
I explained that here: http://blog.blackoise.de/2016/03/building-a-lc-filter-for-your-nrf24l01-palna-module/.@Oitzu Thanks for the hint! That might actually have been a reason why it worked for some time and then stoped, right? I have ordered the components needed and will test it soon.
I don't actually use the LM2596 modules but these smaller ones but I guess they use similar parts.Did you have similar issues?
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@LastSamurai can't really say for this modules.
The datasheet for the LM2596 says you should use a post ripple filter for low noise, because it generates sawtooth ripple at its switching frequency (150khz). The china-clones of the lm2596 seem to be even worse generating even greater ripple with 50khz.Whats the ic on the mini dc-dc converter called? The ebay offer says it has a output ripple of 30mV bute more then often these values are the best case. Maybe a datasheets is available.
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It would be so useful to be able to measure the supply voltages with an oscilloscope. So far all my transmission problems have been related to the power supplies. Only after using a scope I fully realized that. No more freezing or poor function of the nodes.
Also, using a brand supply doesn't necessarily mean a clean signal. This (again) is an illustrative post about USB supplies, worth to take a look at:
http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html -
It would be so useful to be able to measure the supply voltages with an oscilloscope. So far all my transmission problems have been related to the power supplies. Only after using a scope I fully realized that. No more freezing or poor function of the nodes.
You are totally right! Unfortunately i also don't own a oscilloscope. But a cheaper usb oscilloscope is on my need to have list because of a all the trouble and testing i had with this...
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It would be so useful to be able to measure the supply voltages with an oscilloscope. So far all my transmission problems have been related to the power supplies. Only after using a scope I fully realized that. No more freezing or poor function of the nodes.
You are totally right! Unfortunately i also don't own a oscilloscope. But a cheaper usb oscilloscope is on my need to have list because of a all the trouble and testing i had with this...
@Oitzu DSO138 scope is like $25 from aliexpress
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@Igor-Katkov said:
DSO138
Was thinking of something like the Hantek 6022BE. Most EE guys would say "eh... crap", but oh well.. it's just a hobby and i'm not willing to pay hundreds of dollars for it. :D
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One might think that to measure ripple noise of $2 Chinese power supply ~$70 unit is an overkill :-)
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@Igor-Katkov eh... now you just sound like my gf. :P
No, you're right. But it may come handy in some other situations. :) -
It would be so useful to be able to measure the supply voltages with an oscilloscope. So far all my transmission problems have been related to the power supplies. Only after using a scope I fully realized that. No more freezing or poor function of the nodes.
Also, using a brand supply doesn't necessarily mean a clean signal. This (again) is an illustrative post about USB supplies, worth to take a look at:
http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html@Nuubi My two cents.. I have been measuring (with a scope ;)) quite a lot of power supplies and have come to the conclusion that most (inexpensive) switching power regulators (buck & boost) should be avoided when a clean supply is needed. All (or most) of these just not have enough filtering (LC) for the switching frequency. So go for a 'linear' version (for buck/ step-down), especially for the radio. Also PIR sensors are very sensitive.
Lucky for us most MySensors circuits need very little power, so the efficiency of a linear converter (for buck) is sufficient in most cases.
from digikey
or use a linear converter as "second stage"
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@Oitzu Looks like the chips are these.
Btw I am using a cheap DS201 and I am happy with it for most cases. Sometimes I wish for a second channel but you can carry it around which is a big plus :)
@AWI I have to convert 12V to 3.3V which is a big jump. So you think a linear regulator would work here? Something like a LM 1117 T3,3? Doesn't that get too hot if I constantly power the arduino, the radio and potentially a sensor?
PS has someone tried this? Otherwise the second stage LDO (something small, smd) would be an idea too. -
@Oitzu Looks like the chips are these.
Btw I am using a cheap DS201 and I am happy with it for most cases. Sometimes I wish for a second channel but you can carry it around which is a big plus :)
@AWI I have to convert 12V to 3.3V which is a big jump. So you think a linear regulator would work here? Something like a LM 1117 T3,3? Doesn't that get too hot if I constantly power the arduino, the radio and potentially a sensor?
PS has someone tried this? Otherwise the second stage LDO (something small, smd) would be an idea too.@LastSamurai No problem at all if you solder it on a copper plane. Most sensor circuits take less than 20mA.
I actually use the 662K LDO as a second stage with a step-up converter, works like a charm.
For the LM1117 (=not a real Low Dropout) the input voltage can be up to 20V.
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@LastSamurai https://www.adafruit.com/datasheets/MP2307_r1.9.pdf
seems to be more complete and well.. a filter or a second stage would be recommend.@AWI i'm actually have a project running from 12v lead batteries, best way would be to use 2 stages?
ATM i'm using an additional lc-filter to get the ripple out. -
@LastSamurai https://www.adafruit.com/datasheets/MP2307_r1.9.pdf
seems to be more complete and well.. a filter or a second stage would be recommend.@AWI i'm actually have a project running from 12v lead batteries, best way would be to use 2 stages?
ATM i'm using an additional lc-filter to get the ripple out. -
Could you perhaps actually use the onboard voltage regulator of the pro mini for powering the mini + nrf + random sensor? That would be the easiest + cheapest methode. Perhaps add one cap.
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@LastSamurai depends on the used onboard regulator and the used nrf + random sensor.
But yes, this works also, most of the time on non pa/lna modules. -
@Oitzu in case you are looking for a cheap DIY osci, I'm going to build a Girino (http://www.instructables.com/id/Girino-Fast-Arduino-Oscilloscope/?ALLSTEPS) when I find the time. There is also an frontent on github (https://github.com/Chatanga/Girinoscope/tree/v1.0.1-beta). Seems to be quite simple and with very cheap hardware, so don't expect too much. But to have a look at some voltage levels and ripple it might be ok.
And when using it with a battery powered laptop you should be even ok with potential-free measurements. -
@mfalkvidd Yes, a few more meters with PA_MAX.
Here is my best performing coderadio.setPALevel(RF24_PA_MAX); radio.setDataRate(RF24_250KBPS); radio.setPayloadSize(4); radio.setChannel(2); radio.setRetries(15, 15);Full code https://gist.github.com/ikatkov/6df540838bd4d3ea8b57
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@sven on the video he shows 83.38 ?? you are right, it is 2.4GHz
1/4 wave antenna is 31.25 mm long
1/2 wavelength is 62.5mm.so why did he mesured 83.38 ? was it inches ? (imperial non universal?)
I'd be surprised if the existing on board antenna is anything else than a 1/4 wave length of the center frequency for the NRF24L01 module. Therefore I BELIEVE that the right thing would be to extend it with antother 3/4 to make it a full wave length.
If you run it at the default MySensors frequency which is 2476 MHz, a full wave length is 121 mm. Therefore I'd assume that adding another 91 mm to the existing antenna would be the correct length. I haven't tried it yet though but I will.
Cheers!
