nRF5 action!

rmtucker

Could anyone tell me why the waveshare board is pulling 140uA when sleeping with everything unpugged including the usb and all the header jumpers so only 3.3v and ground fed to the header pins so not using the regulator etc.
I have attached a link to the schematic hoping some circuit wiz might be able to explain.
link text

If i unplug the core board and just power that with 3.3v and gnd it only uses 5uA when sleeping.

mtiutiu

@rmtucker

Even if you're not using the regulator and the CP2102 usb-serial converter there are some leakage currents which are caused by the output stages of those IC's. For example the output stage of the voltage regulator can draw some even if it's not powered. The CP2102 can draw also through the TXD1/RXD1/SUSPEND1 LEDs and the associated GPIO pins P0.11, P0.09, etc.

So to prove and test that the above it's true you need to:

Desolder the RT9193-33 or at least its output pin(Vout pin 5)
Desolder R6, R7, R10

This is what I can conclude by looking at that schematic. Any other opinions?

NeverDie

@mtiutiu said in nRF5 Bluetooth action!:

Any other opinions?

Yes. If it really matters that much, RMTucker should buy or make a uCurrent Gold. Otherwise, he'll find hmself chasing phantoms. I have a Fluke 87V, and I don't trust it to do these types of measurements (I've tried, and the results are just wrong when compared to a uCurrent Gold). I would trust a crappy multimeter even less. Been there and tried that already.

Just my two cents.

NeverDie

BTW, uCurrent Gold is open source. I have an original, but you can buy clones. For instance, LowPowerLab sells a clone. You might get it faster than ordering from Australia.... unless you live in Australia. Dave Jones did a video for me once, and so I thought he deserved the profit instead of somebody else. :)

Nca78

@NeverDie said in nRF5 Bluetooth action!:

@mtiutiu said in nRF5 Bluetooth action!:

Any other opinions?

Yes. If it really matters that much, RMTucker should buy or make a uCurrent Gold. Otherwise, he'll find hmself chasing phantoms. I have a Fluke 87V, and I don't trust it to do these types of measurements (I've tried, and the results are just wrong when compared to a uCurrent Gold). I would trust a crappy multimeter even less. Been there and tried that already.

Just my two cents.

It just depends on the burden voltage, no ? It's proportional to current in the circuit so in sleep mode when measuring around 10 uA it should be negligible.
Anyway I measure when powered with 3.3V so I'm sure what I measure is higher than what I will get in reality when circuit is powered with a 3V battery.

mtiutiu

For measuring small currents I'm using Texas Instruments EnergyTrace piece of technology and it works pretty well. You just need one of their development boards with energytrace special microcontroller embedded which is very cheap. More infos here: http://43oh.com/2015/09/how-to-measure-an-energia-applications-power-usage-with-energytrace/

It can be used to measure other boards power usage also - you just need to take of some jumpers and plug in your external board.

It gives you real time energy measurements and with plotting too(and battery life estimation is displayed real time too). No need to worry about burden voltage and other external factors which affect the measurements.

NeverDie

@mtiutiu
I think maybe the nRF52 DK also has some energy measurement capability, but I haven't looked into it.

Toyman

@NeverDie
https://devzone.nordicsemi.com/tutorials/28/

NeverDie

Looks like I was wrong earlier about the voltage reference being Vcc when doing an analog read on a pin. Instead, it seems to be a fixed reference. In any case, I'm getting better results with an expression like this, which is independent of Vcc:

millivolts = (analogRead(PIN)*3000/4095)

What are others here doing in this case?

rmtucker

@NeverDie
As mentioned earlier by someone the nrf52 is preset to 0.6v internal ref and a 1/5 divider so 0 - 3v is the max input so your calculation is correct.
The nrf51 is different because the ref can be set to a few different settings but the default is vdd.

rmtucker

Is RSSI reporting implemented in the NRF5 setup yet?
If so how is it done?

scalz

I don't think sendSignalStrength function is implemented yet, but you should be able to get this info with:

int16_t transportGetSendingRSSI(void)
int16_t transportGetReceivingRSSI(void)

Toyman

How can I redefine UART pins in nrf51822? For example, if I want to have p13 as uart tx?

scalz

@Toyman
it has been explained above in the topic ;)
you have to follow

rmtucker

@scalz
Rssi works really well.
Thank you.

rmtucker

So range test.
Using esp8266 with standard nrf24 not amplified gateway at one end of the house.
Nrf51822 node in garage which is not fastened to house so at a guess 15m through 3 brick walls is reporting -86db.
I think that is quite respectable.;-)

Toyman

@scalz thx.

Omemanti

Regarding the PCB/KiCad comments.
I was trying out KiCad and copied the NRF52832 DC/DC schematic from the datasheet.

It might be of help for someone.
https://github.com/Omemanti/KiCAD/tree/master/NRF52832

PS. been at KiCad for a couple of hours, been used to Eagle, so please double check.

NeverDie

@rmtucker said in nRF5 Bluetooth action!:

@NeverDie
As mentioned earlier by someone the nrf52 is preset to 0.6v internal ref and a 1/5 divider so 0 - 3v is the max input so your calculation is correct.
The nrf51 is different because the ref can be set to a few different settings but the default is vdd.

I've lately found that I seem to get a more accurate measurement if I multiply by 3131 instead of 3000. Just an empirical result with no real theory behind it.

gohan

I don't know if it is actually related, but I'll post the link to this programmer :)
adafruit.com/product/3571

nRF5 action!

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