RF - Very Low Power Comms & Simple  - Page 1
Forum section: electronics / beginners

author: lunar
author_rank: Contributor
timestamp: April 15, 2020, 06:01:48 am
content: I'm looking for an ultra low power communication solution for an Attiny10 micro.These have 4 IO, which is the first limit - it must be simple. The second limit is the power supply. I'm looking to run these either off solar panels and a supercap, or batteries. I've initially decided on RF & LoRa. Based on this, I've gone with the RN2483, which is controlled by UART, which the tiny I assume can manage in software, if I code it beforehand.I've considered alternatives to RF for such an application:No IR as this requires line of sight.No ultrasonic, as I don't trust it.Are there any other options overlooked?I don't know if there are any other RF options that would be worth considering. LoRa seems popular, although it is not as low power as I would like. Perhaps even a simple FM or AM transmitter would work (e.g. FM bug). I do not use RF often.If anyone is interested in general Attiny10 resources, there are some proto pcbs I built here:https://git.steakelectronics.com/Electronics_Projects_2020and some information on setup of the chips, details, etc.

author: Manul
author_rank: Super Contributor
timestamp: April 15, 2020, 10:42:53 am
content: So it needs just TX? How often and how much? 433 Mhz modules are often used in remote thermometers, remote controls. They are not power hungry if you send data rarely and very simple to use. But due to band congestion it is not the most reliable solution. Also BLE can be efficient, but more complex.

author: lunar
author_rank: Contributor
timestamp: April 16, 2020, 06:20:06 pm
content: A bit after I wrote the OP, I realized that TX will probably be enough. I will want to double check that.For how often to transmit, this is essentially a breadboard project, so I want to be able to transmit infrequently for some applications, and then frequently for others (data logging). I've narrowed down what sensors are available at my price range / IO pin use / low power, and I have the following options:Low (power/cost/IO) sensors:hall effectcurrent sensemovement (analog accelerometer)temperature/humiditycapacitiveI wonder if I missed anything.Something like a hall effect would be infrequently. But temperature or current sense I might want more often.I will look into 433MHz. I'll update anything I settle on, either here or on the git repo. I forgot a layer in the URL - have to add adminguy before the repo, so adminguy/Electronics_Projects_2020the ideal, would be something that transmits frequently, and yet uses very little power (and has reasonable range). Then these can be used for detailed data logging. Maybe there's a solution that isn't RF at all (but not wired).

author: Manul
author_rank: Super Contributor
timestamp: April 16, 2020, 09:04:19 pm
content: The way to transmit frequently and have good range and low power usage is to use high bitrate transmitter, which transmits short packets of data and goes to sleep mode, thus having low TX duty cycle and low average power. 433Mhz modules will not be very good at that, because they are kinda low bitrate. Things like amount of data in one packet, packet rate, TX power usage and TX bitrate needs to be put into calculation to see what average power usage you can expect from different types of transmitters.