The WORKBENCH part 3

(Amedee) #82

No enclosure yet :roll_eyes:
So I left it on the floor in the garden shed…
Same temperature as outside, a bit less moisture (hopefully)


for sure


LTH5200 series is a LoRa based temperature and humidity sensor.
Soon on the workbench for a review, the very first, hope to find the right ‘style’

(Amedee) #85

Here it is…


Temperature dropped only to -3, but the LiFePO4 battery voltage has been stable throughout the night, no drop with the temperature.

I need to look more in details to the data, because I have 2 gaps in the graph. The device didn’t crash as the packet counter didn’t reset. It might be unrelated as I also have gaps with other nodes (e.g. the orange line) and this is very unusual…


select max(temperature),min(temperature),last(temperature) from environ where dev_id = 'bulles-minilora-01' and time >= now()-24h

time                           max  min  last
----                           ---  ---  ----
2019-01-21T08:31:20.274882581Z 22.5 -2.8 -1.3


select max(voltage),min(voltage),last(voltage) from environ where dev_id = 'bulles-minilora-01' and time >= now()-24h

time                           max  min  last
----                           ---  ---  ----
2019-01-21T08:35:21.574417311Z 3.28 3.27 3.27

Missing points:

select * from environ where dev_id = 'bulles-minilora-01' and time >= now()-24h

time                           analog_input counter data_rate dev_id             humidity pressure rssi snr   temperature voltage
----                           ------------ ------- --------- ------             -------- -------- ---- ---   ----------- -------
2019-01-21T22:21:28.504029864Z              2322    SF7BW125  bulles-minilora-01 80       1009.8   -84  9.25  -2.1        3.27
2019-01-21T22:31:36.201477425Z              2324    SF7BW125  bulles-minilora-01 79.5     1009.7   -84  8.25  -2.2        3.28
2019-01-22T06:17:32.845840515Z              2416    SF7BW125  bulles-minilora-01 77.5     1001     -83  9.25  -1.8        3.28
2019-01-22T06:37:48.487811162Z              2420    SF7BW125  bulles-minilora-01 77.5     1000.6   -83  7.75  -1.8        3.27

So I am missing 1 packet at 22:21Z and 3 at 06:17Z.
I don’t have gateway logs to cross check, but given the fact that frame counter was incremented, it looks like the node sent them but got lost…

(Petaluna) #86

My test with LiFePO4 failed during the night. Temperature was -5 degrees Celsius. So this battery type is not better than Lion in these cold environments :frowning: Note that I enabled brownout detection on the MCU; it would have stayed alive longer if I had disabled that feature.

(Amedee) #87

Strange – temperature in Brussels was a couple of degrees higher, but I don’t observe any voltage drop…

(Petaluna) #88

I did also place the sensor boxes on the cold soil in the garden outside.

(Jezd) #89


I’d put off playing with these boards (Lora Node 1.0) for ages and after playing with one last night I am warming to them now, do we have a thread for them? if not can we create one and I will add some notes/comments,

PC 433Mhz/868MHZ/915MHZ lora module SX1278SX Module ATmega328P Wireless DIY Kit for Arduino pr…

This was on my workbench so I posted here :slight_smile:

(Remko) #90

Interesting to know your experience. A separate thread is good I think.

(Bsiege) #91

A good chance to kill these is also the often ignored fact that these chemistry can/should not be charged below 0°C. There are many (solar) charging circuits out there which do not implement this.

(Petaluna) #92

I disabled the brownout detector and now the batteries work fine in the cold :slight_smile:


Fire!!! My NEW budget test rig caught fire and 18650’s went off like rockets.
Cause: overheating and I had not installed a BMS yet, was undercharging instead which clearly was not enough.
source: FB group DIY Powerwalls

(Amedee) #94

That does not surprise me…

Too many people still have to understand that LiPo batteries are really dangerous and need to be handled with care.

I am not saying you can’t do it in a safe way, but a power wall is much more than just putting a bunch of cells together.


a bunch of OLD cells … :wink:






‘job’ today … get that '2.2 TFT working and measure what’s the total consumption (sleep/no backlight)




Sparkfun info - voltage dividers and levelshifting


That are great boards when you need more IO and memory. :ok_hand:

Have used them in various projects.




Product Introduction:
1.Driving Port Signal Voltage:3.6-24V
2.Output Port Voltage Port:3.6-30V
3.Jumper Cap Can Achieve Output Port Is High POtential Or Pull Down Output
4.Onboard 4-Channel 817 Are Independent:can achieve different voltage control at then same time

The input port is shared with GND;
The output ports are independent of each other;
Optocoupler output V and G will be connected after valid input signal.



  • A $500 wireless router
  • A $3 'pluggy boi

0 voters