What if the names are exactly the same? 

Posted by: Lab Coat

Test 
 
 

Posted by: Lab Coat

So I decided I needed a little more data regarding how much current the RPi used at various points in time, and with various peripherals attached. So without further delay ... 
 
Test setup: Tektronix TM5006 with PS5010 & DM5110, RPi zero W; 32GB class 10 card; wifi on; VNC on; with and without Apple keyboard and mouse; with and without external LCD monitor; with and without camera module hooked up and/or turned on; and/ or streaming video. 
 
1) During boot, no external peripherals, wifi on: ~250mA (peak) 
2) During boot, with keyboard & mouse, wifi on, monitor attached: ~450mA (peak) 
3) During boot, camera module attached, wifi on: ~ 250mA (peak) (no discernible increase from attached camera) 
 
4) Steady State, no external peripherals, wifi on: ~115mA (peak) (typical average also) 
5) Steady State, with keyboard & mouse, wifi on: ~280mA (peak), with mouse movement: ~360mA (peak) 
6) Steady State, with keyboard & mouse, wifi on, monitor attached: ~290mA (peak), with mouse movement: ~385mA (peak) 
7) Steady State, camera module attached, wifi on: ~115mA (peak - no streaming), streaming video: ~ 360mA 
 
#7 is the key for me ... I plan on having wireless cameras around the chicken and duck coops, and the garden, and the yard. The original plan was to use solar to charge Lion battery packs ... but ... I might need a little more power for during the evenings and stretches of cloudy days. A typical 18650 cell has about 2500mAhr of current capacity. So at 360mA (worst case streaming constantly), that gives me about 5.15 hours (when converting from 3.7v to 5v at very high eff.)  

Posted by: Lab Coat

So I received this plant monitor from China recently, and finally had a chance to play with it / tear it down. I would be remiss if I didn't state my disappointment with having to register an email address (un/pw) for usage / access to the iOS app. Suffice it to say but it was a burner address. 
 
More details to come... 
 
Pics: 
 
In the package. 
 
 
It's a little hard to make out, but I see no FCC ID's nor any Bluetooth Sig ID's. 
 
 
Front. 
 
 
Rear. 
 
 
Battery cover removed. 
 
 
Top side of board ... They use a Dialog DA14580 (cortex m0) for BTLE comms. PCB-trace IFA antenna is in upper right quad. Very top is a simple photodiode for light measurement. 
 
 
Bottom side (with battery holder). 
 
 
Closer shot of the Dialog BTLE part. 
 
 
 
Not sure, but I suspect that this is an op-amp. I *think* they use it in the permittivity / dielectric measurement of the water content of the soil. It does NOT appear to be used in the Ion conduction (conductivity) measurement. 
 
 
 

Posted by: Lab Coat

And I recently received my Time Domain Reflectometry (aka TDR) Probe. I have been dipping my toe into the Urban Ag / Open Ag scene over the past couple of years, but this year I'm diving in to the deep end. The is partly out of engineering curiosity and partly out of necessity. 
 
The curiosity part is applying my multidisciplinary engineering background to develop a small scale / robust / wireless sensing network for a large-ish urban farm (see https://www.facebook.com/3acresandabarn/). Ultimately I want to sense what's going on in the earth. Anything and everything that I can sense. 
 
The necessity part is longer term. Kelly and I plan to be here (where we live) for a long time. As we see it, two thing are definitely going to happen. 1 - Energy prices are going to increase (hence the Solar Projects going on at the urban farm - I'll explain fully later). And 2 - Food pricing is only going higher, and supply is only getting tighter. I suppose a third reason is related to the 2nd ... knowing where and how some of my food was grown. 
 
For those that see this in time, there is an OpenAg open house at TechShop in St. Louis on 2/2/17. I'll be there. 
 
 
 
 
 
 
 
 

Posted by: Lab Coat