Saturday, August 27, 2016

SparkFun ESP8266 Wifi Shield: Deep Sleep, Connectivity, and Power

I've been working on a wireless moisture sensor project on and off over the past month or two.  My property is spread out, and I'd like to be able to keep track of soil moisture over time - with the long term goal of controlling irrigation systems automatically from a central command point.  Since everything is spread out, the sensors and controls need to be wireless for both communication and power.

My initial plan involved using the SparkFun ESP8266 WiFi Shield for communication.  Over the past few weeks, I've learned a lot about that shield.  Most of the stuff I learned required piecing together things from a variety of sources - there was no one reference for it.  So, hopefully it's useful to you as well.  Sadly, I also learned that the few boards I ordered have an unreliable U.fl port, and are therefore unsuited to my needs.

It is a good looking device, with nearly all the useful pins brought out to 2.54mm headers.  Or, 0.1" headers.  It exposes almost all the functionality of the ESP8266, has some nice status LEDs (power and "talking to something"), supports both hardware and software serial, has an onboard antenna, and in general is a quite nice shield for $15.

My wireless moisture sensor project, on paper, is reasonably simple.  Some moisture sensors, an Arduino to read them, a solar panel, a charge controller, a power supply, and a wireless gizmo to talk to my network.

However, I've spent weeks trying to make the assembly work reliably.  It would work on my desk, then fail in the project box.  Or work in the project box and fail on my lawn.  It was difficult to reproduce the problems, since they didn't show up on the device side logs, and I couldn't get much out of the device over serial - I was left troubleshooting from my access point (which, fortunately, has good logs).  I finally determined that the problem was with the U.fl connector on these shields.  I also found that some other ESP8266 modules had a nicer power control interface, so I built myself a shield from one of those and went on with the project.

Read on for lessons learned.  May they help you avoid hours of wasted time.

Saturday, August 20, 2016

2014/2015/2016 SkyActiv Mazda3 Oil Capacity & Change Procedures

Things needed for a 2014/2015/2016 SkyActiv Mazda 3 oil change: 5 quarts 0W-20, 6 quarts if you've got the 2.5L motor and are a "top of dipstick" kind of person.  A Wix 57002 filter.  An 8mm wrench or socket, an 8mm hex driver (or Allen wrench), and a medium flathead screwdriver.

Read on for what the oil change process involves.  But that's probably what you wanted to know, isn't it?

Why am I doing a writeup on a 2015 Mazda 3 oil and filter change on a blog focused on electric bikes, solar, and small electronics?  Because I hate Tap-A-Talk full screen annoyances and car forum mobile themes, that's why!  It's rather off in the weeds for my blog, but it took a bunch of searching and a phone call to the dealership (including waiting on hold) to find this information when I went to pick up oil for my car without the actual car.  Hopefully this remains helpful for people going forward.

Saturday, August 13, 2016

BionX 26v 9.6Ah Teardown & 18Ah rebuild

It's been a while since I've done a pack teardown and rebuild of a new pack.  The most recent one was the Trek Valencia Ride+ pack teardown and rebuild back in January (Part 1, Part 2, Rebuild).  That one was a bit of a mess - corroded cells, held together with some sort of adhesive foam, and generally not at all fun.

This one is somewhat nicer to work with!  It's a very welcome improvement.

I have here in my hand a list of 205 a very well used BionX 26v LiMn battery pack.  It's rated at 9.6Ah, and is in the same form factor they seem to use for all their packs.  Interestingly, the capacity is the same as the 36v packs (9.6Ah), but the voltage is lower (so fewer cells).  It could make one wonder...

Read on for tons of photos, a full teardown, and a stunning rebuild to a whopping 18Ah!

If you're just here because you have one of these and it needs to be rebuilt, you probably want to go here for details on the rebuilds I offer.

Saturday, August 6, 2016

Teardown & Review of a $3 Solar Bike Light

It's been a little while since I've torn apart cheap bike lights out of China - but I'm back at it with this solar bike tail light!  And, I'm tearing it apart in my solar powered workspace.

If you'd like one, they're less than $3 on eBay right now.

It's powered by "Solar energy."

It's "solar energy rechargrable" - and it includes a "steaady" mode.

What's in it?  And is it any good?  Keep reading to find out!