Mechanical engineer for a living, but I love these sensors, processors, radios, and programming, for fun.
Some people meditate . . . I prefer to solder.
Another buck regulator that might work:
https://lowpowerlab.com/shop/product/133
Felix used it for a doorbell project and I have used for a thermostat. In those cases, we had to rectify first to get DC, but wouldn't need to since you already have DC.
Arduino Nano 33 BLE code is coming out. It's going to be based on MBED. Here's a discussion on the Arcuino Blog:
https://blog.arduino.cc/2019/07/31/why-we-chose-to-build-the-arduino-nano-33-ble-core-on-mbed-os/
I think it is interesting that no one has updated Sandeep Mistry's code for the NRF52840. Since it has been so long, I'm guessing this is not an easy task.
I think you can just set the I2C pins in MyBoardNRF5.h without remapping the pins in MyBoardNRF5.cpp.
Look in MyBoardNRF5.h, under the Wire Interfaces section. Set SDL and SCA to 30 and 31 as appropriate for your board.
If you have room for a AA, an LiFePo4 battery is right in the sweet spot.
I have seen LiFePo4 AAA batteries, but they are really hard to find.
The RFM69H variants can have quite good range. I have a gateway on my second floor wich receives from nodes in the far corner of my basement with no repeaters. That is just using a single wire antenna (https://www.mysensors.org/build/connect_radio). My NRF24 nodes cannot do this.
There is a short discussion on LowPowerLab that might be useful. It talks about RFM69 range and has some photos of SMA connections for a Moteino using RFM69. See link:
Please report the results. I thought this dimmer chip looked interesting, but it seems to be optimized for manual control with a pot. Like you, I want something to control with MySensors.
Interesting. The pet friendly settings might be useful in my house.
A couple of thoughts.
This sensor wants 12 volts. I have had bad luck with the cheap Chinese Pro-Minis I normally use. They advertise being able to use power up to 12 volts, but they fail quickly at that voltage. You will probably need to power the arduino differently from the sensor.
I'm not that familiar with the Mega 2560, but it appears to have several additional interrupt pins over the regular arduinos. You would just have to pick one and use that in the software.
Did a quick google and someone said the two "T" pins are tamper detection. The NC are motion detection. The tamper detection just tells you if the sensor case has been opened. The two NC terminals appear to be a normally closed switch contact. You could use a simple button setup like this:
https://www.mysensors.org/build/binary
This setup doesn't use interrupts and instead polls the switch pin. The down side is you will not be able to sleep the node.
There may be better ways, but the sample above would give you a quick way to experiment with it.
Do you even need to boost? I have several ds18b20 nodes running on 2 AA batteries with a ProMini 8Mhz and basic low power mods. Wired like here: https://www.mysensors.org/build/temp
I get nearly 2 years on a set of batteries. The ds18b20 seem to work fine at the lower voltages, but I have not tested them rigorously. The output just seems about right.
When a MySensors node can't find the gateway, it will try to find another one or a repeater. That might be what you are seeing. I used the code listed below in a node I was using just as a beacon to tell if my car was nearby or not. It might be worth a try. It tells the node to just stop looking if it can't find the specified gateway.
Note: If you are using a repeater to get to the gateway, then this is not what you want to do.
/**
* @def MY_PARENT_NODE_IS_STATIC
* @brief Enable MY_PARENT_NODE_IS_STATIC to disable fall back if parent node fails
*/
#define MY_PARENT_NODE_IS_STATIC
#define MY_PARENT_NODE_ID 0
The new Arduino Nano 33 BLE is going to use the nrf52840. It will be interesting to see how support for the nrf52840 evolves in the Arduino environment.