Wednesday, November 23, 2022

New Radio Mini Node

There was a little happening on development side of OHS lately. The gateway line 2.0.x
works very stable. No issues found in software or hardware. Arduino based nodes are also reliable. Basically it works as intended, "install and forget". 

But the word is changing and so are the evolution of chips. ATmegas, and also other components are becoming hard to get, and the prices of ATmega tripled. While using STM32 Cortex M4 chips for gateway, I realised they are great replacements, allowing us to do stuff not imaginable on AVR. For example STM32duino, I've been watching the progress of it for long time, and also, I have some blue/black pills on hand. So I decided to give them a try also on OHS environment. I've created a STM32 Radio Node Mini, which render is shown on picture. 

It is 50*24mm board with STM32F103C6T6 Cortex M3 running up to 72MHz with 64KB of flash and 20KB SRAM. Basically well known bluepill. It's meant to be used as radio node, so on back there is place to mount RFM69 or LoRa RFM95/96 module. It has a u.UL connector or place for wire antenna. Board has also 3.7V Li-ion battery charger, and battery measurement resistor divider connected to MCU ADC pin. It is programmable directly via USB port, or it has SWD. There is also RTC quartz crystal which allows indefinite sleeps instead of ATmegas maximum 8 seconds. It has LED on PC13, and also on top a place to mount various temperature/humidity sensors like HTU21D. PCB comes with mounting holes to fit in various places.

Currently I'm having those fabricated, and as soon as I have some of them tested and I'm ready with proper software, I will report more.

3 comments:

  1. Anonymous2/11/24 10:54

    I have the need to install some wireless PIR and would like to know if you have them ready to sell on the site in the future-...

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    Replies
    1. Or you can just join the Discord. We can maybe discuss it there.

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  2. Anonymous2/11/24 17:37

    Hi, I've been playing with wireless PIR's. I have a couple of them. Some are just modules, some are complete product. Let me tell you, the modules, especially some cheap Chinese ones are good only for turning the lights on and off. The Fresnel lenses are a not good and the sensitivity also not great. For PIR sensor, best option is to buy some semi professional one and add the board in as logic between the PIR and the OHS gateway. But this is something I would not sell, since it depends on what PIR you have or buy. Maybe I'm just too serious about the sensitivity :) But I've tested the professional (Bosh, Paradox, Jablotron) and cheep Chinese ones, and there is a hell of difference.
    But if you are willing so sacrifice the sensitivity, then a PIR module and 3D printed box with this radio node and you are good to go.
    For the code I can provide some examples about wireless node with PIR for OHS.
    Also let me know, maybe we can work on something together. Since it would be great option for many more users.

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