Hardware

@Reza Do you have some references to this noise issue? Any papers, etc that proves the theory

@Samuel235 Nice job.. No need for additional grounding. The measuring circuit has the reference as a "virtual ground".

@AWI I agree that it would be nice if it was up to the controller to handle it, and then the units for different measurements sent to it were standardized on (like mm for distance). Also, it would be nice if the controller would allow selection of metric/imperial either by device, or sensor type. For example, I want my distance sensors in mm, but my temperatures in F.

The "Efficiency of Voltage Boosters" thread is full of useful info but has been sleeping for a year so this is an effort to bring it back to life again :-) I have built a few battery powered sensors based on the 328P-PU running at 8MHz as well as 1 MHz. Batteries used are common NiMH size AA + cheap Chinese 3.3V step-up converters. Both the processor and the radio are powered from the 3.3V converter which I understand can be a bad practice. Still I decided to try because I did not want to tamper with the fuses/bootloader at this stage and luckily I have so far not experienced any of the here described connectivity problems. More or less out of curiosity I made a few tests of this setup using different sizes of same brand electrolytic capacitors (nothing fancy, bought as a Velleman high-Q kit, labeled "made in Europe"). The results does not give more info than already available here but it helped me understand and hopefully can help others too. For the test setup a 10µF is soldered to the radio pins and I can add another in parallel through a socket. The unit tested is also equipped with both a 3.3 and a 5V step-up. A photo of the setup as well as a few screen dumps from an oscilloscope are attached as a pdf (hope it works). Readings are taken using a 8 MHz chip programmed as a motion sensor and while the sensor is at rest. 0_1462995658167_Tst.pdf Here is a short summary and a curve of same data: 10 µf dV 76 mV 10 + 22 µF dV 43 mV 10 + 47 µF dV 28 mV 10 + 100 µF dV 14 mV 10 + 220 µF dV 9 mV 10 + 470 µF dV 5 mV [image: 1462995740616-dv.jpg] A bigger capacitor of course lower the amplitude of the ripple (not unexpected :-)) and the rapidly falling curve shows that the current recommendation of 47 µF is a good choice. Adding more will lower the ripple but not at all proportionally. I am not experienced neither in building these battery powered sensors nor in measuring them why any comments/corrections will be appreciated.

I haven't tried it yet but this plugin for serial monitor over network looks nice https://github.com/esp8266/Arduino/issues/1360

Of course you can. Use voltage dividers to scale down voltages that you would like to measure if they are above your VCC. And you can also read the current from TP4056 charger board. Tap to Prog pin (pin 2) and measure its voltage. Here is the correlation between voltage and current: Ibat = (Vprog /Rprog) x 1200 Adapt the above code with your hardware values, current formula and measure away.

So easy ! I finally used directly BRD file and not GERBER. Thanks for the advice on DRU. The strange thing is that I tried with CAM job of OSH Park but the result was the same. But it's working with BRD so let's order my first board :) David.

Thanks! I definitely like V1's compact size (0.8in x 0.9in). Are there any mysensor nodes smaller than that, or is it currently the smallest? The Sensebender is also fairly compact (0.69in x 1.18in), although its effective thickness is much greater because of the way a traditional non-SMT NRF24L01+ gets stacked on it using a header.

@gregl said: isn't the key difference of the two that one 32u4 has a built in USB controller, whereas the 328p doesn't and relies on an external USB controller (FTDI usually.) That's important, but there are many other differences vs ATMega328p. Offhand, there's an extra 0.5K RAM. Second 16 bit timer (Timer3) instead of 8 bit Timer2; plus high speed 10 bit Timer 4. SPI and TWI on different pin #'s (as seen by Arduino). More ADC pins, and a 10x/200x differential amplifier; different voltage ref (2.56v vs 1.1v). And various changes to interrupts or registers based on these. So some less-used libraries need porting, as well as changes to example code. Not sure how these differences affect the core of MySensors; you might have to try it out. There's a good chance that it would work, or that the changes needed would be minor. The Leonardo is gone from the Arduino.cc product line, but the Micro is still sold so presumably the chip continues to be supported.

@signal15 probably talking about http://blog.blackoise.de/2016/02/fixing-your-cheap-nrf24l01-palna-module/? I've not written it, but the foil touches the ground on the antenna socket. So yes, it needs to be grounded. In most cases it even works ungrounded though. Even a ungrounded shield has an effect on the circuit.

Well, it's working now. I put a new power supply on it, and shielded the radio. Before I go dotting my house with sensors, is there anything I should do in MyConfig.h or anywhere else? It looks like debugging is turned on by default. Should I leave it? Also, even though I got it working, any insight to the above questions would certainly still be appreciated. [image: 1462224039067-img_20160502_161633.jpg]

@phil83 Share this on OpenHardware.io !

@Anduril Yea thats what I thought, and I see it. Ill check this out thanks

Thanks for your help guys. Got it up and running now :) I used the pulldown resistors but did not use the current limiting resistors at the gates. Afaik you don't really have to but I will add them in my next version. @Admin I think it would be a great idea to update the build part for the leds to also use these resistors and perhaps add some text for RGB(W) leds as there is support for them now.