💬 Easy/Newbie PCB for MySensors

[Nca78]

Hello, don't waste your CR2032 yet, as it is now you will be lucky to last a few days ...

CR2032 and other lithium cells with the same chemistry have a strong internal resistance. It means the more current you draw from them, the more energy you will waste because of this internal resistance. It makes the voltage drop and it means your battery booster will need more and more current to maintain the output voltage = vicious circle with more and more energy wasted.

Your solution is not to add a battery booster but to use another sensor that will be able to run at low voltage: BMP180/BMP280/BME280 or SHT21/SI7021. They have a very low power consumption (unlike ds18) and will accept Vcc voltage below 2V. I would suggest the SHT21/SI7021 as it's easier to use and will go in sleep mode between measurements without any action from you.

Without battery booster you will also have a much increased range as the booster generates a lot of noise that perturbates the radio.
You will also need to:

• add a big capacitor (at least 100µF) in parallel with the battery to ease out the current peaks
• remove the voltage regulator as it's still on your pro mini at the moment
• adapt your sketch to sleep (with 200ms you should be ok) between all consecutive radio calls. Don't forget to do it in the presentation method as it's the most sensible part, before it's called the library has already done many radio calls that made your battery voltage drop. You should begin the presentation method with a sleep.
• update the fuses on your pro mini to remove the BOD which is by default at 2.7V and will limit the total power you will get from the battery
• use a brand name cell, the cheap chinese no-name cells will have much lower real capacity available, voltage will drop much faster.

[fabix68]

@Nca78 said:

SHT21

Nca78 thanks for the reply.
I did not know the SHT21 sensor, it looks like a good alternative also DHT22.
I've already added a capacitor and view the trace output with the oscilloscope, it is clean, why not explain the decrease in range.
With regard to the program, has been provided for the sending of data every 5 minutes, if it changes from the previous value, to then return to sleep.
I never tried to change the fuse on the PRO. I believe that this is the solution. Run it at minimum frequency, remove the BDO so you can also remove the battery booster.

[dbemowsk]

I am wondering on the Rev 8 boards how much room there is around the outer mounting holes to drill them a bit larger? Is this just a dual layer board or are there other sandwiched layers in it that might be affected if I drill them larger?I have been trying to find a decent way to mount these and stack them with other boards, but I'm not having much luck. The project I am working on right now is a revised board for my garage door controller and I have my power supply circuit on a piece of proto board and I want to stack the newbie PCB on top of it, but can't find standoffs that small, and I am having real trouble even finding screws that will fit the holes. Has anyone done mounting of these? If I can find screws and mounting hardware that will work without having to drill the holes bigger I am all for it.

[sundberg84]

@dbemowsk said:

I am wondering on the Rev 8 boards how much room there is around the outer mounting holes to drill them a bit larger? Is this just a dual layer board or are there other sandwiched layers.

Its a dual board - drill as much as you want, you can see all traces. In my upcoming rev the holes are bigger. I have recieved this feedback and are improving this.

[Lior Rubin]

@sundberg84 said:

In my upcoming rev the holes are bigger. I have recieved this feedback and are improving this.

what should be on the next rev ?

[sundberg84]

@Lior-Rubin Changelog so far:

• Bigger mounting holes 2.5mm
• IRQ Jumper from Radio. This makes this trace disabled and D2 can be used for interupts unless jumper is connected.
• BAT and REG jumpers changed positions for better tracing.
• MysX 2,6
• Text on voltage regulater (Vout/Vin/Gnd)
• Bug with G on CAP now on the right side.

Release and if there will be more things added I dont know.
Any suggestions?

[Qu3Uk]

@sundberg84

In power input I would suggest moving GND to the middle of VCC/RAW so you could using a 2 pin block for GND/RAW like what is shown in post 205. Might cause tracing issues though for you.

[sundberg84]

@Qu3Uk - its a good suggestion.
I will se what I can do.

[Lior Rubin]

@sundberg84 I may suggest the following:

• place for Temp\Hum sensor
• place for Light sensor
• ability to use AC to DC (3\5v) in the board
• ESP8266 option rather than Arduino (maybe 2 versions)
• TX\RX connection or FTDI connection

[dbemowsk]

I had mentioned this before, but the electrolytic capacitors wer put in the design using a ceramic capacitor designation which doesn't allow room for correct placement of capacitors. The main one is the one near the radio. The pads for the cap are spaced too far apart for a small electrolytic, and they are too close to the connector requiring that the capacitor leads be bent toward the radio connector to be able to get it to fit.

[sundberg84]

@Lior-Rubin @dbemowsk - thanks you for the suggestions. I will take them into consideration!

Im not sure I will implement everything because the main purpose of this PCB is to keep it SIMPLE. Its a newbie/easy PCB and to many components and/or other things will make it hard for new members to use.

[rchamp]

@sundberg84

I agree with sundberg84 here. Would it be nice to have those other features? Sure, but then you're limited to what else you can do. This is a GREAT board for many/most sensors around the house. And in regards to light or temp/hum, in my experience it's better to have these detached and in better location for detection while keeping "main" board. more out of sight.

I'll post up some pics of my builds for ideas, but I've built sensors with temp/hum, temp/hum/motion (both battery powered running for over 7 months) and my latest a Neopixel multi strip driver for kitchen cabinets using 5v regulated power. And I haven't had any issues with the cheap through hole ceramic caps for .10uf or the electrolytic caps for 4.7 or 10uf sizes on this board

[rchamp]

@rchamp

Only issue I've have was with resistor to D3 which I don't use. My first board I put a resistor there and when doing a trace noticed I was constantly getting regulated 3.3v and it fried my dht11. Might Have been I interpreed the purpose of it wrong as I am new to electrical engineering, but I digress. I just power the dht of of vcc and gnd in prototype area and wire sensor outpUT directly to D3 breakout. No resistor.

My biggest challenge is finding/building quality quick connects for quick changes and mods /addons. I've reverted to Barrel connectors as they're easily available and can get pigtail versions and panel mount Versons easily

[dbemowsk]

I too agree with @sundberg84 and @rchamp. You ask for a spot for all these different sensors, well it has it with the small proto area. If you make it specific to certain sensors you are limiting it's flexibility. the proto area as it sits is big enough, if I want to put a temp/humidity sensor, light sensor, motion sensor or whatever else, I can wire the connectors in the proto area. If anything, I might say to make that proto area even one row bigger in each direction to give a tad more room for maybe resistors or capacitors that may be needed for some sensors. May give a little more flexibility for if you wanted to do a multi sensor board.

@Lior Rubin, you said "ESP8266 option rather than Arduino " did you mean "ESP8266 option rather than nRF24"? Also,why would you need to put an TX/RX or FTDI connector. IF you use pro mini , it has the FTDI connector on it already.

[velkrosmaak]

@sundberg84 I hit this post again today with the intention of finally biting the bullet and buying some boards - but then I saw your notes about the next revision of the board. Could you tell me when you're expecting to release that? Is it worth me waiting a while?

Thanks!

[sundberg84]

@velkrosmaak - I dont know - im in the middle of another project and it wont be any bigger changes.
See the changelog above.
Only thing that can matter if you planning to do a project with 2 interupts that need D2 and D3,

[Lior Rubin]

@dbemowsk said:

@Lior Rubin, you said "ESP8266 option rather than Arduino " did you mean "ESP8266 option rather than nRF24"? Also,why would you need to put an TX/RX or FTDI connector. IF you use pro mini , it has the FTDI connector on it already.

I meant to use the ESP8266 option rather than the pro mini+nrf24. So to transfer the sensors to use IP and not radio.

for the FTDI, the connection on top of the arduino board is hard to connect because of the terminals.

[dbemowsk]

@Lior-Rubin said:

I meant to use the ESP8266 option rather than the pro mini+nrf24. So to transfer the sensors to use IP and not radio.

for the FTDI, the connection on top of the arduino board is hard to connect because of the terminals.

As for the FTDI connector, you have a few options. You can switch the right angled header pins for straight ones and plug in vertically. Option 2 is to mount it reversed pointing away from the terminals. Option 3, which is what I do, is to mount the Pro Mini with female header strips on the board. The ones that I use bring it up high enough where the FTDI connector clears the terminals if I use them. Doing it that way gives you the added benefit of being able to remove the pro mini and swap it if there is a problem.

[Nca78]

@sundberg84 said:

Only thing that can matter if you planning to do a project with 2 interupts that need D2 and D3,

Even for that the current version is not a big problem. Just cut or unsolder the interrupt pin on the NRF24.

[pettib]

Hi
Do anyone have a working sketch for a 2xAA battery powered DHT22 with Mysensors 2.0 that works with this pcb rev.8 ?

//PT