Hi, I’ve finally made a real project with an Imp, although a simple one.
I’ve made a button which I’ll hit each time I have a (good) idea. A precomposed tweet with a timestamp will capture this moment.
(BTW, I work in advertising, ideas are our core business, but good ones are rare and hard to find)
So here’s the repo: https://github.com/mezelve/Eureka
The button is attached to the wakeup pin so the battery should last …
Any feedback would be much appreciated.
Very pretty. With the button doing wakeup you shouldn’t even need the on-off switch, as the imp sleeps using so little energy. Looked at your code and the only thing I see is that your LED won’t be on for long as you sleep immediately after sending your eureka event - might want to pulse the LED a bit before going to sleep 
How does that Xively thing work?
Nvm… I just figured it out… Had hoped for not having to copying all that into the agent.
Does anyone have a good mounting solution for the april breakout?
This is also the first time I had something laser cut. What’s the best way to clean the edges of plywood?
@Hugo
Thanks for your feedback. The LED just pulses twice to confirm it.
What do you think of my hardware.voltage() solution to be notified when the voltage drops below 3.0V? I noticed that the Imp doesn’t work anymore below 2.9 - 2.8V.
The imp will work under 3.0V but you’ll lose the ability to bring up WiFi. Preferably, you would use something inline with your battery that has an undervoltage lockout. Sparkfun’s Powercell LiPo charging circuit has this. I believe one of the Adafruit boards does as well, though they don’t advertise it.
One of the easiest ways to “mount” an April is just to attach it to a small prototyping board, like Adafruits mini prototyping board. It has holes that you can attach to standoffs or screw down or whatever. Double sided tape and hot melt glue work great too.
The imp is actually fine down to about 2.6-2.7v including wifi, BUT that’s the real voltage the imp sees, not what the voltage looks like outside a transmit burst
@mezelve in your schematic you have 4xAA. Are you seriously getting these down to below 3v? That’s some dead batteries. There’s not usually anything left in AAs below 1v.
@jwehr
thanks for the feedback
@Hugo
I did a test with my Hannah where it pinged every 15 sec. It took quite some time but in the end it went offline at around 2.85V.
Yeah, I expect in that case the internal resistance of the cells was so high that as soon as wifi came up, the batteries tanked well below 2.85v and the system gave up.
That’s 0.7v per cell, which is beyond dead
