💬 Easy/Newbie PCB for MySensors

[JPM]

Dear sundberg84, thanks to your really nice and easy mysensors PCB. I ordered ten of them via SEEED and they were delivered today (REV.10). Unfortunally I found some serious bugs in the PCB design regarding the SPI Flash: First pin 6 (SPI SCK) of the flash chip is not connected at all - should be digital IO pin 13 of the Arduino pro mini. Second mistake: the filter capacitor of the flash chip is not between VCC and GND. Third mistake: pin 3 and pin 7 should be connected to VCC and not to the filter capacitor. I changed that on my arrived boards and the flash chip is now working perfectly. Kind regards, JPM

[mickecarlsson]

I checked the schematic, and:
First mistake: Seems that the schematic is OK, the label for SCK (pin 6) is connected to physical pin 16 which is PCINT13 on the Arduino,
Second mistake: that is a bug, filter capacitor is not connected correctly.
Third mistake: That is also a bug, pin 7 and 3 should be connected to VCC
Now I am going to check the PCB, be back shortly,

[mickecarlsson]

I have now checked the PCB, and you are right @JPM
Pin 6 of the flash chip is not connected at all. No wonder I could not get that to work. Strangely is that the schematic is OK.
Thanks for finding this, I will modify my boards to get them working.

[sundberg84]

Sorry for this. The flash has been untested by me. I will fix this asap and upload new files.

The schematics is wrong:

New schematics:

The same error goes for RFM version :(

[Eme]

@mickecarlsson I found this out and wrote it above that D6 is not connected at all... but it was promptly swept aside cos nobody had reported it before now. I am glad someone else saw it, and that you had the notion to check. D4 is also not connected to the test area. I have been connecting directly to the Nano.

[sundberg84]

@eme im sorry - since your wrote "The provisions to attach sensors are not correctly marked. D6 doesn't actually connect to D6 pin on the Arduino" I thought you was talking about the MysX connector and not flash. If you mentioned flash I would probably found the issue. They are not talking about D6 but pin 6 on flash which connects to D13 on the Arduino.

Are you sure it's the same problem? Not much that sounds the same.

[mickecarlsson]

@sundberg84 if you look at the schematic you have connected MySX pin 10 to D2, but according to the spec for the MySX 2.4 it should go to D4.

[sundberg84]

@mickecarlsson - I understand your point, and I have changed this back and forth and also asked @Anticimex becuase its a but unclear in the documentation.

MysX 9 + 10 should go to a Digital IO with interrupt, and D2 and D3 is the only pins with interrupts on mini.

I guess you are refering to Mysx_D3_INT but this is the MysX name.

[Anticimex]

@sundberg84 @mickecarlsson
It is important to remember that MYSX is agnostic from any devices.
Any names in MYSX pins bear no correlation to any device specific pin naming, so D3 and D4 mentioned on pin 9 and 10 has nothing to to with any D3 or D4 on any MCU.
If you look here, you will find that the 'A' and 'D' notation is simply an indicator of the pin function (analog or digital) and it simply increments with the pin number, so the lowest analog or digital pin number in the MYSX connector will start at '1' and then increment as the pin number increments with '2' for the next digital being on pin '6'.
Also note that since some pins are deprecated in MYSX 2.x, MYSX 2.x analog pins starts with 'A3'.

[birinderk]

I was wondering if there are any CAD files for corner through hole size/locations for Rev 10? Trying to design enclosure for it.

[dbemowsk]

@birinderk SHould be easy enough to measure it with a caliper. That's what I did with the earlier revisions of the board (rev 8 & 9). They had pretty much the same hole spacing. Here are a few of the enclosures/sensor cases that I did that fit the rev 8 and 9's.
https://www.thingiverse.com/thing:2186286
https://www.thingiverse.com/thing:3339158
https://www.thingiverse.com/thing:2904969

[sundberg84]

@birinderk - https://github.com/sundberg84/HomeAutomation/tree/master/MysX template EasyPCB

[markjgabb]

Does anyone know where we can find the write ups for old revisions? i have a bunch of Rev9 boards that, now that i have restarted these projects after a year break i cant remember the write ups for them....

[mfalkvidd]

@markjgabb do you mean the stuff in README.md in the zip file that can be downloaded on the revisions tab?

[markjgabb]

@mfalkvidd yeh i guess so, not quite what i was after the orignal in that version had some good pictures and such of what went where on the board....do doubt i can work it out from an old dead one i have lying around, was just hoping for a nice visual guide to get me back into it.

[mfalkvidd]

@markjgabb not sure if this is what you want, but if I paste the contents of the readme into a markdown viewer (for example https://dillinger.io/ ) I get the images:

[markjgabb]

@mfalkvidd ahhhhh That answers my question perfectly....i was just dumping it into notepad ++ ill try that first thing in the morning.

[fredswed]

Hi,

First of all: I really appreciate the simplicity and flexibility of this board!

Now then, I have a problem with battery life which is only around 3 weeks for my DHT22 node and around 8 weeks for my BMP280 node. Both are 3.3V mini clones with NRF24 radios (probably clones) that run on 2xAAA batteries and a booster. I use NodeManager for software and report sensor values in 2 minute intervals. LED and voltage regulator has been desoldered from the Pro Mini.

Why isn't battery life better - am I missing anything obvious?

1. Can/should I remove C2 (10uF) and C3 (0.1uF) capacitors? I added them first but after checking the schematics I now think they are not used at all for the battery/booster setup?

2. What battery life can I expect for a BMP280 on 2xAAA batteries and booster?

3. New batteries report at 3.13V. When the nodes fail, reported battery voltage is around 2.6V. However, when measured I get it to around 1.6V (at no load). This could be a software problem but I include it as a clue. My setup in NodeManager is:

battery.setBatteryPin(0);
battery.setMinVoltage(1.8);
battery.setMaxVoltage(3.1);

[sundberg84]

@fredswed - Hi!
You should be able to get much longer batterylife than this! I have same setup running around 12 months.

It is hard to say, your setup in the image looks correct. Sometimes when i bought boosters or sensors they draw much more current than expected due to clones. In these cases I try to solder pro-mini and radio, then connect a multimeter in series with the batteries to analyze current consumption - then add sensor by sensor to find out what is drawing current - is this possible for you?

1. The are used for the booster to smooth noice, so both can be used in your setup.
2. 2xAA with DHT22 = 1 year, BMP280 has a low current consuption when sleeping so it should be able to do atleat 1 year there as well.
3. I dont know nodemanager. The booster should boost the voltate for VCC, so it depends on the specs for your booster.

My first thought is that your BMP module is always active drawing alot of current even though you put the node to sleep. Test current consumption during sleep. Should be < 100uA and even maybe 50 uA atleast!

[Nca78]

@fredswed hello, are you sure you booster is wired correctly and running fine ?

Node failing around 2.6V looks a lot like the value before the default brownout detection (2.7V). Then when you are at this level the node will be in a reset loop forever and completely drain the battery, but of course your node will not be able to report it.

So I would check the wiring and behavior of the boosters as they don't seem to do their jobs. I might be wrong but it would be a strange coincidence to have both nodes failing just at the brown out voltage.