![\"CaptureStatus\"](\"https:\/\/logicalelegance.com\/journey\/wp-content\/uploads\/2014\/04\/CaptureStatus.jpg\")
<\/a><\/p>\nI couldn’t find anything about that in their documentation. But it is worrisome so I tried to remove it. My efforts led to my card not updating and the system not running at all. The error I got was unsatisfying.<\/p>\n
In my ayok widget, I have a battery. To make it last, I want the high power things to sleep as much as possible.<\/p>\n
The Electric Imp is the largest power consumer, followed by the accelerometer, and then the battery-monitoring fuel gauge.<\/p>\n
Happily, the Imp has a low power mode. When I say imp.sleep(5.0) to sleep for five seconds, in low power mode. Though it isn’t a very low power mode, for one thing, the WiFi remains powered up.<\/p>\n
They offer another mode, a deeper sleep more: imp.deepsleepfor().\u00a0In deep sleep, it consumes only 6uA (which is a tiny amount if you are a cell phone and a medium-to-large amount if you are a wearable device).<\/p>\n
Foolish me, I thought I could replace my imp.sleep calls with imp.deepsleepfor calls, do a little bit of tweaking (i.e. tell the server I’m going to sleep), and it would work.<\/p>\n
Suddenly my system kept crashing.<\/p>\n
I feel like that represents my often-rocky interactions with Electric Imp. I still think it is a good platform for hobbyists but it is often deeply frustrating. When I first started working with (playing with?) the Imp, I wrote an in-depth review\/rant detailing its shortcomings. I opted not to post it here, instead sending it to the Imp folks in hopes my time and frustration could help them make a better product. Some of those things have gotten better in the intervening six months but many things got worse. Let’s just say I wouldn’t dream of using it in a product and if things continue to be bad, well, there are other options for home hobbyists.<\/p>\n
Anyway, back to my crashing system.<\/p>\n
It turns out that sleep() returns to where it was but deepsleepfor() restarts execution. This is clear in their examples (but not documented in the text). There is a work-around: if the non-volatile RAM is configured, then the system has been booted before. If it has not, then this is a cold-start so I should configure the accelerometer. (I very sincerely hope that “reprogram the code” is considered a cold-start and erases the nv space.)<\/p>\n
As a developer, I understand why this happens this way, my annoyance is primarily because I feel like they hid it from me. No, they probably didn’t. But yes, their documentation should be better.<\/p>\n
I did fix the crashing (and not through their nv hack, instead they have a function that can tell me what the reason for the wake up is:\u00a0hardware.wakereason(). Yes, I did implement the nv hack before finding that.<\/p>\n
Now, my Imp isn’t crashing any more. I made some tweaks, trying to get rid of the slightly alarming note in the logs:<\/p>\n
[Status]\u00a0Device disconnected; 585 bytes sent, 0 received, 585 total<\/p>\n