Search found 9 matches

by moose
Tue May 05, 2015 11:47 pm
Forum: Drivers for External Components
Topic: Library for Debouncing, Counting Pulses, and Averaging Analog Signals
Replies: 8
Views: 6992

Re: Library for Debouncing, Counting Pulses, and Averaging Analog Signals

@cloudformdesign: I'm glad the library looks useful to you. As to your comments: - It would be fairly easy to accept *either* a Pin object or a string for the required first parameter. I can test the type of the parameter and act accordingly. To preserve the "description" parameter, we'd have to sep...
by moose
Wed Apr 29, 2015 3:28 pm
Forum: MicroPython pyboard
Topic: low power support?
Replies: 26
Views: 10472

Re: low power support?

@manitou: I powered the pyboard from Vin and Gnd, which made it easier to put a 1 ohm resistor in series with the Vin lead. I then used my PC scope (PicoScope 2205) to measure the voltage across that current sense resistor--1 mV equals 1 mA of current. It is important that scope ground is isolated f...
by moose
Mon Apr 27, 2015 4:11 am
Forum: MicroPython pyboard
Topic: low power support?
Replies: 26
Views: 10472

Re: low power support?

Is there any way to reduce the amount of time and/or current required to come out of pyb.standby()? I ran a do-nothing program to determine how much current (actually, charge) is consumed during the bootup after pyb.standby(): import pyb rtc = pyb.RTC() rtc.wakeup(2000) pyb.standby() Here is the tim...
by moose
Fri Apr 24, 2015 4:51 am
Forum: General Discussion and Questions
Topic: Self sufficient (solar powered) pyboard?
Replies: 11
Views: 5811

Re: Self sufficient (solar powered) pyboard?

Yes, those are some nice power number on the WiPy. I'm a backer, but I hadn't looked closely at the power consumption. Just as a start at estimating average current draw across a 15 minute cycle of reading sensors, posting data across WiFi and then sleeping. It seems like there are two choices: 1) k...
by moose
Fri Apr 24, 2015 3:01 am
Forum: General Discussion and Questions
Topic: Self sufficient (solar powered) pyboard?
Replies: 11
Views: 5811

Re: Self sufficient (solar powered) pyboard?

I did some modeling of storage and PV requirements for a pyboard drawing a particular amount of average current. It sounds like you're not certain what that average current draw is, so I expressed results in a way that can be applied to any level of average current draw. The needed PV and storage ar...
by moose
Thu Apr 23, 2015 9:07 pm
Forum: General Discussion and Questions
Topic: Self sufficient (solar powered) pyboard?
Replies: 11
Views: 5811

Re: Self sufficient (solar powered) pyboard?

One issue with the SEEED Studio board is efficiency in this particular application. The board charges the LiPo battery, but then boosts the battery voltage up to 5V before delivering to the load. If 1 Amp-hour goes into the battery from the solar panel, with the voltage boost, at most 3.9 V / 5 V = ...
by moose
Tue Apr 21, 2015 7:30 pm
Forum: General Discussion and Questions
Topic: Self sufficient (solar powered) pyboard?
Replies: 11
Views: 5811

Re: Self sufficient (solar powered) pyboard?

The Adafruit people have thought about this quite a bit, and here is the solar charger product they came up with: https://www.adafruit.com/products/390 . They also sell LiPo batteries and 6V Solar panels that match the charger. If I knew your location, orientation of the panel, and an idea of what y...
by moose
Mon Apr 20, 2015 5:42 am
Forum: Drivers for External Components
Topic: Library for Debouncing, Counting Pulses, and Averaging Analog Signals
Replies: 8
Views: 6992

Library for Debouncing, Counting Pulses, and Averaging Analog Signals

I just released a Micro Python library that makes it easier to do certain tasks with input pins. Here is the link to the Repo on GitHub . My motivations were: I wanted to be able to debounce digital inputs in software and run callback functions when the digital inputs changed state. I wanted to be a...
by moose
Fri Apr 17, 2015 4:44 pm
Forum: Hardware Projects
Topic: Sun Tracker
Replies: 7
Views: 4856

Re: Sun Tracker

Great project! The "short-circuit current" of a solar panel is linearly related to the amount of solar radiation incident on the panel. So, it would be most accurate to place a dead short across the panel and then measure the current. However, it's a bit of a pain to measure current; here is a break...