I have been looking at the Enviro Urban to supplement my Particulate data (my current setup only collects PM2.5).
The summary indicates that collecting Particulate data is power consuming, so I was wondering about using a solar system to power it. I’d rather collect data more frequently than the 1-3 hrs recommended. Given I have to power the sensors and the pico all off the same source, I expect I may need to mod the LiPro to 500mA.
My current setup sends data by the minute, and runs on Solar/Battery. I seldom have to bring it in to charge at the wall outlet. It was a commercial product, though. I’ve never ventured into DIY power.
I’m looking to do a solar project too, though it’ll be powering a CCTV installation. I hope to start measuring current requirements next week, once my long-awaited Zero 2 arrives.
The best approach may be to buy your components and measure their usage. A USB multimeter can be used to see what your out-of-the-box current draw would be, and it’ll help you experiment with approaches to reduce current draw.
The main thing for both of us is probably to ensure that the battery is juicy enough to sustain overnight usage when the solar panel isn’t operational. This current usage calculator gives me some hope - apparently a Zero with a 12,000mAh battery can shoot HD video for ~28 hours before running out (I am making the assumption that the Z2 consumes a similar amount of power to the Z1). That suggests that this 8,800mAh battery would do ~21 hours, for the same load, without sunlight.
I’d suggest reducing this though - do particulate conditions change so frequently that per-minute monitoring is necessary? I’d have thought a sample every 10 or 15 minutes would be better - I should think it would change based on vehicular traffic levels and changing weather/temperature conditions, which will generally change slowly within the 24 hour cycle.
Thanks for that info. Looks to me like this is going to be a rabbit hole I don’t really want to invest time in at this stage. Guess I was looking for a quick answer: e.g. someone had the equipment to test it and worked it out already.
I did check the data on my PM2.5 and it does send every 10min (its just the console sends data every minute). So 10min would be sufficient. However, the guidance on the product is 1-3hrs to keep your AAA batteries lasting in months. This is not a compromise I’d make (the PM2.5 does fluctuate in those 10min intervals).
I’ll mull it over, but I’m sure my brain will conjure another rabbit hole I can go digging in over the next few days
I’ll answer my own question in case someone does stumble on this and wants an answer.
I did not use the LiPro Amigo, but rather a solar power supply module (PSM) from DFRobot. One thing about the enviro urban is that if you power it from the USB, it will never go into deep sleep mode (this is documented). Deep sleep is only for battery.
Saying that, my PSM with a 5V solar panel and a 2500mWh Li-pro battery did run off the USB all night fully charged. Some of that charging time in the day was when the Urban was also running. I eventually got some wires and now run the Urban from the battery terminals (the PSM supports both USB and 5v outputs). So my Urban will deep sleep for 10min intervals to wake up and take readings.
Unfortunately, the current firmware version of the Urban no longer reports battery voltage due to issues (hopefully a firmware update will fix this). I am quietly confident I won’t run out of battery power overnight. It is summertime here, and my battery is fully charged by about 11am, so it should be good even during shorter winter days or cloudy ones.
Disclaimer: just remember DIY power and Lithium batteries are a dangerous combination. Both the battery and PSM I purchased have overcharge protection circuits. Don’t go cheap on either.
Fitting it all in the case was a challenge, but doable. The battery is cable tied to the back with the Enviro and PSM velcroed on. The PSM gets hot (heat sink at the back). I don’t trust the temperature reading from the sensor (i have a separate gizmo for that).
