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SFUptownMaker

Member Since: July 5, 2011

Country: United States

Profile

Role

Electrical engineer

Programming Languages

Python, C/C++

Universities

NDSU 1997-2002

Interests

Toys, tinkering

Websites

uptownmaker.blogspot.com

Radio Shack is finally declaring bankruptcy, but for many of us, it died a long, long time ago

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FTDI's latest driver update appears to be semi-permanently disabling counterfeit FT232 chips.

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To compare the Edison and the Raspberry Pi is to do a disservice to both.

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In which I buy a cheap truck, planning on using my hacking skills to keep it going, and the universe calls my bluff

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When in New York, I found a small group of hackers in as surprising place

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Quad Fever!

Quadcopter fever is spreading through SparkFun! Of course we're going to hack them.

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How Python makes my life easier every day

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Technological befuddlements it took me 10 years and a college degree to understand.

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New!

Wake-on-Shake Hookup Guide

March 13, 2015

A basic hookup guide for getting started with the SparkFun Wake-on-Shake.

BC118 BLE Mate 2 Hookup Guide

January 15, 2015

Hooking up and using the BLE Mate 2, which uses the BC118 BLE module from BlueCreations.

Programming the Intel® Edison: Beyond the Arduino IDE

January 7, 2015

Intel's Edison module goes beyond being just another Arduino clone. Check this tutorial for advice on how to get the most out of your Edison by writing code in C++!

RedBot Sensor - Wheel Encoder

December 25, 2014

The RedBot Wheel Encoder allows you to track the number of revolutions each wheel has made. Learn how to assemble and work with the RedBot Wheel Encoder.

FemtoBuck Constant Current LED Driver Hookup Guide

October 16, 2014

The FemtoBuck board is a high-efficiency, single-channel constant-current LED driver.

Sunny Buddy Solar Charger V13 Hookup Guide

October 13, 2014

How to hookup the Sunny Buddy: a solar-powered, MPPT (peak-power tracking), LiPo battery charger.

FTDI SmartBasic Hookup Guide

October 3, 2014

How to use an FTDI SmartBasic Board to program an Arduino and access another serial device over the hardware serial port, without unplugging anything!

RedBot Assembly Guide Rev 02

September 2, 2014

Assembly Guide for the RedBot Kit. This tutorial includes extra parts to follow to go along with the RedBot Inventor's Kit tutorial.

MiniGen Hookup Guide

May 22, 2014

Using the MiniGen, SparkFun's Arduino Pro Mini signal generator shield

Understanding the BC127 Bluetooth Module

January 31, 2014

SparkFun has two boards using the BC127; here's what you need to know to use them.

Digital Logic

October 3, 2013

A primer on digital logic concepts in hardware and software.

MiniMoto DRV8830 Hookup Guide

September 19, 2013

MiniMoto is an I2C-based low-voltage DC motor driver.

Getting Started with the AutoDriver

September 9, 2013

SparkFun's AutoDriver is a powerful tool for controlling stepper motors. Here's how to use it.

PicoBuck Hookup Guide

August 30, 2013

The PicoBuck board is a high-efficiency three-channel constant-current LED driver.

Using GitHub to Share with SparkFun

August 19, 2013

A simple step-by-step tutorial to help you download files from SparkFun's GitHub site, make changes, and share the changes with SparkFun.

Getting Started with the RedBot

August 8, 2013

A simple introduction to SparkFun's RedBot robotics platform.

I2C

July 8, 2013

An introduction to I2C, one of the main embedded communications protocols in use today.

Leap Motion Teardown

June 27, 2013

Let's see what's inside the amazing new Leap Motion input device!

Programming the pcDuino

March 12, 2013

With great power comes great complexity. This tutorial will teach you some of the basic concepts needed to get the most out of programming your pcDuino.

pcDuino Hookup Guide

March 8, 2013

pcDuino is SparkFun's single-board hardware-hacker based mini PC. It comes with Linux pre-installed, has all the hardware functionality of an Arduino Uno, and can be programmed almost as easily as an Arduino!

Light

February 7, 2013

Light is a useful tool for the electrical engineer. Understanding how light relates to electronics is a fundamental skill for many projects.

Connector Basics

January 18, 2013

Connectors are a major source of confusion for people just beginning electronics. The number of different options, terms, and names of connectors can make selecting one, or finding the one you need, daunting. This article will help you get a jump on the world of connectors.
  • It should. The 4.0V float voltage was selected because that prolongs the life of the battery; you can change those resistors to get to 4.2V if you really think it’s important, but it gains you very little extra energy.

  • There’s a good reason not to do that: signal integrity on the D+/D- lines.

    It might work, some or even most of the time, but in the end, it would be a feature that invites trouble in to stay. It’s a far better solution to connect the USB to the device that has USB connectivity, and then pull the 5V off that to feed the Power Cell (or whichever charger you’re currently using).

  • You may find that at 900mA your power inductor starts to saturate. That’s dangerously close to the 1.05A spec limit of the part. Also, 5V is too low a voltage; the SunnyBuddy won’t start up below ~6V.

    Put the panels in series, and you’ll probably be okay; in a step-down system, the inductor current shouldn’t be too much higher (if at all) than the output current.

  • R2, R6, and R7 all need to be adjusted, and the directions for setting those values is in the datasheet.

  • It certainly looks as though something should be commented out, but isn’t, or isn’t being read as commented out.

  • This picture shows it as it would be installed on the robot; the ball-caster end of the robot chassis would be toward the bottom of the image.

    There are X, Y, and Z markings on the picture showing the orientation.

  • Usually, that means Eclipse can’t find the file in question.

    Generally, a Google search on the specific text of the error message will find an answer, or at least give you an idea of where you should start looking.

  • There’s a diagram for a 2-cell LiPo from 12V wall adapter that will work; the only difference is the set voltage of the input side divider. That you’ll need to figure out based on the solar cells you’re using.

    Raising the voltage is one part of the equation; however, for best results you want to balance the cells continuously. Charging is really a current-mode operation, rather than voltage mode: you push a certain current into the cells until the voltage of the cells reaches a defined set point.

    Say the set point you want is 4.0V per cell (a decent target; below 100% but it’ll give you a bit more life). That’s 8.0V when you have two cells. Without some extra circuitry, you have no way of knowing whether that 8.0V is 4.0V and 4.0V or 3.95V and 4.05V or whatever.

    It’s a guarantee that one of the cells will charge more slowly (or less efficiently, if you prefer) than the other. Even a small difference will add up over time, and eventually, you’ll have one cell well ahead of the other. At some point, one of them will be at the maximum healthy level for a LiPo (4.2V) while the other is still low enough that the sum will be less than the set point of 8.0V we chose earlier (i.e., 3.8V or less). The charger will still be pushing the current in, trying to get the sum voltage up to the set point, and then you can have trouble. Either the safety cut-off trips and you get a partial charge, or the “good” cell (the more efficient one) pops. Either way, it’s not what you’re after.

  • Yes. Take a look at our schematic and change out the components to match what’s in the datasheet and you’ll have it.

    I’m not a big fan of that sort of charging, though, because the cells can become unbalanced, resulting in overcharging of some cells and undercharging of others.

  • You can connect this directly to an audio source for streaming over Bluetooth, or you can stream audio via Bluetooth to this and dump the output out to headphones or a single-ended line-in (like the aux port on most stereos or computers, for instance).

HaterMatic

SFUptownMaker 15 items

Wish list for the March 2014 SparkFun Live project: the HaterMat…

AutoDriver Hookup Guide

SFUptownMaker 38 items

This wishlist contains everything you'll need to follow along wi…