EasyPCB and rfm69: Do I need a DC/DC step up booster

[kiesel]

Hi,

I am trying to build a battery driven door sensor using EasyPCB and a RFM69 radio.

The linked documentation says you should use a DC/DC step up booster, but here says the booster creates a lot of noise that disturbs the radio.

Do the newer EasyPCB revisions take this into account but the documentation has not been updated? Or should I attach a step up booster (those, maybe?) and hope for the best?

Thanks!

[nagelc]

You can definitely run the RFM69 on 2 x AA batteries without the booster. I think it depends more on the sensors you want to use. Some PIR motion sensors, for example, don't operate well with voltages much below 3V. There are several different kinds of temperature sensors that do operate well at lower voltages.
The Easy PCB seems flexible enough to do it either way. @sundberg84 gives directions for setting up without booster further down in his description at the OpenHardware.io link you posted above.

[sundberg84]

@nagelc - correct, its possible to use without booster - but its harder depending on which sensor you use. If the sensors require minimum 3.3v it might be hard to do without booster, but there are several sensors managing down to 2v or so.

The harder part of using EasyPCB without booster is that the BOD on atmega328 chip is normally set to 2.8v so when the battery goes below this the chip shuts down. So you have to edit the fuses and change BOD if you want to use it below 2.8v

Everything mentioned here is described on openhardware.io - look for the section Battery without a step-up booster (advanced users)