next topic »

[on:]

Good morning,
we are working on an experimental weather station based on seeeduino stalker v2.3 and Seeed Studio GPRS Shield v 1.4.
Since the station should be compact and energy-efficient we powered the system with a very high capacity LiPo 3.7v connected to the stalker power ragulator and a 1W solar panel.
When the GPRS try to connect (absorbing the stated short 2A peak current) it turns off.
We tried with a 220microF capacitor between GRD and +5V, GRD and +3.3V, and also between the GRD and VBAT pins following the indication of power supply for the Evola GPRS

(https://docs.google.com/open?id=0B6Qn4nam5VvfZTQ4YWQ4ZTctYTYyOC00OGMzLThlMTQtYzgwMGJhOWRiYTY1)

The GPRS only works if we provide an external 5V power supply.
Is there a way to power it up with just the LiPO?

Thanks in advance for any suggestion, we are at a dead point!!

Jacopo & Alessandro

[Reply #1 on:]

Hello, I realize that your post is a little older and that you may well have solved the issue you were having. I'm also having an issue with controlling the power consumption of a GPRS shield that uses the SIM900. Based on the reading I've been doing it ought to be possible to turn the unit of and off via the PWRKEY pin, so software control of the state of the GPRS is possible. The issues around time to boot and acquire a signal as well as testing the availability of the device and cellular service are a little more troublesome, not to mention resource intensive. I"m beginning to wonder if, given the spartan resources on the seeeduino stalker how I'm going to do all of this housekeeping and not run out of space.

Anyhow, I hope you've made some inroads to your issue and wish you all the best with your project.

B