IoT based gas sensing
I am designing a gas sensor system for an IoT application. My system contains different gas sensors(at present 8 nos).The sensor data swill be connected to a potentiostat IC and this IC will be connected to TI CC1352P(Transmitter) and the data from this TI CC1352P will be send to another TI CC1352P(Receiver) sitting 1Km away.The receiver output will be connected to a PC.
My planned architecture is given below. It contains 8 gas sensors.For each gas sensor outputs a separate MUX IC is used.
The CE pin of all IC's are connected to MUX-1, WE pin to MUX-2 and RE pin to MUX-3.The receiver TI CC1352P will poll each sensors at regular intervals,if any gas crosses the threshold Transmitter TI CC1352P will send the data to RX CC1352P.Other than polling if any gas crosses the threshold the system should provide an interrupt ,and at that time also the TX will send data to RX.
This is a battery operated system and it should run for 7 days without recharging.The default state is sleep and it will wake up at regualr intervals and polls the sensors.Also if the receiver wants to wake up the transmitter it can do that.I am planning to use Sub Ghz communication
May I know your thoughts about this system.?
I know polling method can work.How do I wakeup the TX based on interrupt.(I mean if any gas crosses the threshold when polling is not happening)
1 answer
The following users marked this post as Works for me:
| User | Comment | Date |
|---|---|---|
| newbie | (no comment) | Aug 11, 2025 at 20:06 |
Unfortunately, multiplexing three-wire gas sensors like that is a bad idea:
- It will take quite a long time for a gas cell to recover and stabilize before producing meaningful readings.
- The gas sensors will be abused, with possibly degraded lifetimes. These things usually require two of the electrodes to be shorted when not in use, otherwise reactants can build up at one end, eventually rendering the sensor useless. Didn't you receive the sensors with something shorting two of the leads?
It looks like your gas sensor IC has standby capability in which it draws very little power. Note that during standby, the IC shorts the appropriate electrodes. There should be one dedicated sensor IC for each sensor, then you can multiplex the outputs of the sensor ICs.
We will poll the gas sensors at regular intervals of 15mts.In between if any gas sensor crosses the threshold it should wake up the TX and send data to RX.
Your statements are inconsistent with each other. If you are going to poll the gas sensors every 15 "mts" (minutes?), then you can only discover the gas threshold got crossed at those times.
It appears that your RF transceiver includes a programmable processor, although I only looked at the datasheet quickly. That processor needs to poll the sensors at least at the interval that is the maximum time that you need to know about high gas concentrations at. If all the gas levels are below the threshold, then it goes back to sleep. If either any thresholds are exceeded or a whole regular transmission interval has elapsed, then it sends all the gas levels over the RF link.
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