Hardware

Thanks Kimot. I did use 3,3V voltage as the radio NRF24L01+ is supposed to run on 3,3V only. I did not realise that it affect the crystal frequency. When I now tested with 5V it works perfectly! I will purchase an 8Mhz crystal instead and try it all on 3,3V with a step up booster 1,5 -3,3 to 3,3 V with AA batteries. Regarding the "broken" pro mini - I must have broken something else too, as after removing the connection in front of the sms led it unfortunately stopped responding to communicate. So I must have destroyed more than just the LED. Anyway, I am happy I was able to built my own "arduino node" with only the chip, crystal and few capacitors and resistors. It is great to see it working! Thanks for your help.

@qqlapraline The 5v and 3v3 pro-minis can both be modified to very similar low power consumption, Google low power pro-mini for a multitude of sites over several years detailing comparatives and examples. I had reason to dig into this as explained below: With combined radio and RTC on a 3v3 pro-mini I was faced with a lack of available pins from the combination to deal with the 5v ultrasonics as well as providing voltage step-up. I tried a plethora of potential solutions before realising it was a losing battle with a single device and so many demands. Adding a low power 5v pro-mini to the node to deal with the US and communicating via I2C to the 3v3 pro-mini ended up the most efficient solution for my case. It may seem counter intuitive to waste energy on two devices and two power sources, but not so, both sleep saving energy. In my own case I was going to end up with two devices and two power supplies anyway, but just two separate radio nodes, so there was no energy penalty. The 5v pro-mini has one interrupt triggered by the 3v3's RTC for US readings, the second interrupt is to be enabled by the adjacent Gas Meter reed sensor, releasing the original dedicated node for other duties. It is not completed and deployed yet as it is still sub-zero here and the ground is rock solid where the sensor head has to run.

I guess so, I was using development branch at that time, so I am expecting to work the same on 2.2

Small enough to be used with doors (their rubber seal).

@sander-teunissen I think the app just connects individually to each blind according to what you need to control

@sundberg84 right, but both boards have to be swapped. So boards won't be "off the shelf" if one of the two is swapped.

take a look at capacitive soil moisture sensors.

https://forum.mysensors.org/topic/1790/pro-micro-hookup-and-code did you read it already?

Welcome to the MySensors commmunity @thecricketer! You would probably be better off minimizing power consumption of all components (see https://www.mysensors.org/build/battery for some recommendations and post a list of your components for more specific advice) but yes, what you are suggesting is possible. Easiest way: use 2 2xAA battery holders. Connect + (red wire) of both holders to Vcc on the device and - (black wire) of both holders to gnd on the device. Done.

@gohan, Thanks for reading and your response. Since posting I've continued to learn and have found the MYSController program which answers my question regarding the convenience to adding sensors to the gateway.

@johnrob said in Best sensor for quantifying magnitude of vibration?: While not specifically answering your question... would loctite help? Yes, I think it would help. Not very easy to apply in this situation though, because most connections are t-nut without much thread pushing through to the other side.

For 8051 cores there's the SDCC project but I don't know how stable/mature is and/or what are its limitations. And it's a C compiler only as far as I know.

@mahesh2000 please don't post the same question in multiple places. It wastes people's time when some details are available in one thread and some details in another thread. To anyone responding to @mahesh2000's question, please reply in https://forum.mysensors.org/post/85838 instead.

@nerukam 10 moisture sensors only requires two analog ports. You don't want the sensors on all the time or they will corrode away quickly, so you always turn them on and off with a transistor anyway. One end of the sensor goes to Vcc. The other end of the sensor goes to the an analog input. The sensor/analog input is also connected to a resistor. The other end of the resistor goes to the transistor's collector. The transistor's emitter goes to ground. A digital output goes through a resistor to the transistor's base. A second sensor goes in parallel to the first with it's own resistor and goes to it's own analog port. The exact values of the resistors isn't critical but 4.7K should be a good value for all of them in a 5V system. To read sensor X1 and X2, turn digital output X on, read the two analog inputs and when done, turn it off. Repeat this 5 times and you have 10 sensors using 2 analog and 5 digital pins. For even better sensor lifespan, use an H bridge and switch the direction of the current on each read. (design left as an exercise for the reader.) You can actually connect up to 8 sensors to each digital output for a total of up to 48 soil moisture sensors on a single Pro Mini + NRF24 and more if you want to resort to port expanders. (As stated before, port expanders are not really realistic due to them costing about the same as a whole Pro-Mini.) Not all Pro Minis expose all 8 analog pins, choose one that does if you want the most possible sensors.

Not only a genius, the founding father of the SenseBender series Himself :bow:

@rozpruwacz - one more thing you can do is to place a small ceramic capacitor (like 1nF to 10nF ... or just experiment with other values) in parallel to the thermistor, that will also filter noise.