Hi all,
I’ve ordered 3x RAK4631 and 1x RAK19007. Mounted one of the RAK4731 onto the RAK19007 and flashed the firmware. It works just fine.
Then i soldered a Li-Ion battery with a short cable on the GND and “3V3” Pin. This Pin does not run on 3.3 V at all. In fact this is the battery voltage level, and the battery becomes charged up to the expected 4.20 V, also that’s fine. Now when i disconnect the board from the PC by pulling the USB cable, the module runs on battery, as expected. Fine.
But, now, when i disconnect the 4631 from the 19007 board, the 4631 does not work any more, although the battery is still connected to the 4631. WHY??
For a Router it is not necessary to have that large board and that green blinking LED, a waste of energy!
What do i have to change, in software, to make that running?
Or did i flash the wrong firmware? What is the difference between firmware-rak4631-2.0.12.2400dd4.uf2 and firmware-rak4631_eink-2.0.12.2400dd4.uf2
Otherwise i probably need to bridge some contacts on that hardware interface but it appears not likely that this is the ideal way to go…
Thanks for the feedback.
I will search and find a way to avoid using the base board permanently. It is simply a waste of energy, space and money.
The datasheet of the RAK4631 tells that the consumption during sleep mode is just 2 µA. Relative to 2 µA, the average current consumption of a blinking LED is probably at least a factor of 100.
please write here, when you get the 4631 running without a baseboard. that would be interesting.
if you just want to save some space, you can still get the 19003 base-boards, that are a bit smaller …
Yes i will report. And i guess this is possible without much effort. I didn’t yet start attempting because i just got the modules yesterday and i don’t have the tools here at the moment. But in a few days…
I expect that you just have to bridge maybe just one contact, of course by soldering. Eventually the reset button simply interrupts the power supply during it is pressed (i.e. a normally closed contact)?
That will be solved!
have you measured the mA going into the Rak-device?
As long as there is nor messages being sent, its relatively close to zero
so i would not epect longer runtime from removing base board with LED and stuff…
the energy used, ist 99,9% when sending messages, up to 150mA or more depending on tx-level.
So, as long as your Board does transmit a few messages every day, the leds will not drain your battery, the messages will do.
further more, when intended use is router/repeater, i would expect it to be a stationary device with big antenna , maybe big battery and a little bit of solar. So saving Space by removing the tiny base-board is not important.
I would like to have a supertiny device for a gps tracker device, but since the 4631 does not have gps , itis not helpfull here… for attaching gps module you would need 19903 baseboard …
Using the existing tested designs and materials from RAK as your starting point is really recommended, building your own base board without making use of the existing work that has been done is really frustrating for the firmware developers as it is not really interesting to re-invent the same wheel over and over again in an attempt to save $9.
@SR7673 For working with only 3.3v power input you need to connect together 44,43,20,21 pins on the RAK4630 module or solder all NC R0 resistors related to power rails.
Here is ref:
I still don’t get the obsession of running the core without the minimal 19003 baseboard. For the few bucks extra you get the serial adapter, charge controller, solar interface and most notably mounting holes. The miniPCIe Project of @D4rk4 is way cool though …
@garth Surprise for you, sometimes people design their own boards or use “RAW” core modules not only to save money. RAK baseboards did not cover all use cases. But good start for prototyping.
For example, designing and producing a small test batch (5 pcs) of the simple board to bring the RAK4631 module to a standard Router/PC/Laptop costs about 800 USD.
Well, let’s start:
First i want to thank D4rk4 for the section of the schematic. You have been earlier than me I just arrived at my Lab and just wated to measure and watch the schematics to find the results you published…
Now, RAK advertises the module 4631 with “Ultra-Low Power Consumption 2.0 uA in sleep mode” (RAK4631 WisBlock LPWAN Module Datasheet | RAKwireless Documentation Center).
However, when you put the 4631 into the 19007 and do a real measurement of the current drawn from a LiIon battery, you will measure something in the range of a few mA, of course during the periods when the transmitter is off and device.role is Router.
To visualize that current i took a scope and measured across a 1 Ohm resistor, so the resolution in the image is 2 mA/div.
See the attachment.
There is a permanent value of 2 mA + a periodic peak value of 7.8 mA. I estimate the average to be 4 mA, which is 2000 times higher than 2 µA (datasheet). And i bet that the 7.8 mA peak comes from the blinking LED.
I will now do the modification and come back with measurements from 4631 without 19007.
BTW 4 mA means discharging a fully charged 18650 battery in a month.
My battery has 4.07V. I measure (4631 still connected to 19007):
Pin 20 = 4.07 V
Pin 21 = 4.07 V
Pin 19 = 3.3 V
Pin 44 = 3.59 V
Pin 43 = 3.33 V.
Absolute maximum ratings for the chip is 3.9 V. Recommended is 3.3 V (2.0…3.6 V). So it is not wise to connect a LiIon battery directly. However a LiFePo4 cell could be connected directly. And LiFePo4 is a better choice anyway! But does the firmware handle the lower voltage without complaining?
The firmware does not shut down RAK4630-based devices in low-voltage conditions. Due to a bug in voltage detection on this board. Also, a shutdown device is a very strange solution when it’s working in off-grid systems =) Don’t worry about this (for now).
I just arrived at my Lab and just wated to measure and watch the schematics to find the results you published…