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- This topic has 3 replies, 2 voices, and was last updated 2024-02-16 at 2:15 PM by
Shannon Hicks.
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2024-02-13 at 2:03 PM #18314Hello,
I am part of a team of Student Engineers from Minnesota State University creating a Sensor to measure CO2 concentrations in sub-surface soils. Check out the GitHub –
Hello,I am part of a team of Student Engineers from Minnesota State University creating a Sensor to measure CO2 concentrations in sub-surface soils. Check out the GitHub – https://github.com/bellahenkel/Soil-Sensing-Device this was created by Last semesters wonderful team.
We are using the Alphasense IRC-a1 CO2 sensor with NDIR CO2 transmitter board. The issue is the board appears to be browning out when we are switching the vacuum pump on and off. I do not necessarily have a specific question, more just looking for anyone else that has dealt with this sensor or a similar issue.
Excited to be part of this community,
Max
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2024-02-13 at 5:20 PM #18315
What version of the Mayfly board are you using? And how are you powering the Mayfly? Is the Mayfly providing the power for the sensor and vacuum pump too, or is that from a different source?
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2024-02-13 at 6:26 PM #18316Hello Shannon,
We are using version 1.0. The whole system is powered using a Voltaic brand 12volt battery. The voltage is stepped down via a DC-DC converter to power the Mayfly. The pump is powered b
Hello Shannon,We are using version 1.0. The whole system is powered using a Voltaic brand 12volt battery. The voltage is stepped down via a DC-DC converter to power the Mayfly. The pump is powered by the battery and is switched on/off with a relay bank which is controlled by the Mayfly. The CO2 sensor is also powered by the battery, as it requires 12 volts. When the system was powered with bench top power supplies everything was working nicely, only when we connected everything to a single battery did these issues arise. We have attempted to fix it by adding capacitors, which did not work. We are planning to do a closer study of what is going on while switching the pump on/off as well as the relays and solenoid values. Then we should be able to take a more targeted approach to solving this issue.
Any advice or direction you may have will be greatly appreciated.
Max
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2024-02-16 at 2:15 PM #18322I found a schematic in your github repo, my suggestion would be to power everything external to the Mayfly with its own beefy power source, especially the relay bank. It looks like you’re currI found a schematic in your github repo, my suggestion would be to power everything external to the Mayfly with its own beefy power source, especially the relay bank. It looks like you’re currently using the main 3.3v regulator of the Mayfly to power the relays and maybe some other things, which is probably what’s causing the brownout. There’s a secondary 3.3v regulator that powers the SWITCHED_3V output (and the switched 5v and 12v circuits too), so that would be a better source for external devices (just leave pin D22 high all the time to leave the switched power outputs constantly on). Most big external loads on the Mayfly should be connected to the switched outputs in order to provide a more stable voltage for the processor and other vital on-board circuitry. Also, all of that power the Mayfly is providing to itself and all the peripherals has to run through the bq24074 charge controller, which handles all the power going into the Mayfly from either a battery or USB power (and also back out to the battery for charging), and sometimes it doesn’t like surges from motors and other heavy instantaneous loads. So try powering that relay bank (and any other load) from an external source (making sure to tie all the grounds together for common reference) and see if that corrects your brownout issue.
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