johndavid400

Member Since: February 27, 2009

Country: United States

Profile

Programming Languages

Arduino

Universities

UAB

Expertise

motor-control, R/C interfacing

Websites

www.rediculouslygoodlooking.com

Publications

Make Magazine #22

  • News - OSHW DC Meetup and Survey | about 2 years ago

    Good luck Nate, They will hear you, you’ve done it right. ~jd warren

  • Product BOK-10764 | about 3 years ago

    This book is one of the best intro to electronics books I have ever read. It has useful information on everything from electron flow to solid-state electronics with detailed descriptions and diagrams of diodes, transistors, inductors, relays, etc..
    It is still my go-to book when I need to look up a symbol or description for quick reference. You will definitely not be dissapointed with this book.

  • Product COM-10213 | about 3 years ago

    I used the bigger brother of these mosfets, the FQP47P06 p-channel and the logic-level FQP50N06L n-channel to build a few high-power motor-controllers - using three of each mosfet in parallel for each switch in the H-bridge. They worked well, more info here:
    http://www.rediculouslygoodlooking.com/site/triple-8.html

  • Product BOB-08882 | about 3 years ago

    hows about getting a version of the ACS714 like Pololu?? A +/-30amp version is a bit more suitable for robotics. I have used them and they work very well, would probably fit on this board.

  • Product WRL-09132 | about 3 years ago

    This board works great… except for using the Xbee Pro models. They use close to 300mA and the Explorer board’s regulator can only supply 150mA!
    When sending commands with 1 second intervals, I have no problems (I assume this does not over-stress the regulator and it can supply these intermittent bursts of power), but when trying to send a steady stream of commands, the radio on the Pro models tries to draw more current than the Explorer boards can handle, therefore the voltage regulator overheats and temporarily shuts down, at which point you will notice a huge lag in the commands being sent/received (while the Xbee restarts after having lost power). This happens at every serial speed that I tested (1200, 2400, 9600, 19200, 38400, and 115200).
    I would highly recommend replacing the onboard micrel 5205 voltage regulator (150mA) with the micrel 5219 (500mA) or better on all of the Sparkfun Xbee explorer boards. This would allow them to truly support the Xbee pro models. I’m sure the customers of Sparkfun would be happy to pay an extra $0.50 for a beefier regulator.
    Otherwise, it works well!

  • Product SEN-10010 | about 4 years ago

    Works well for angular positioning, but the gyros idle a bit lower than the accelerometer… when reading these from my Arduino via the 10-bit Analog inputs (with Aref tied to 3.3v), the accelerometer outputs centered right at 512 when “level” (scale of 0-1023) - while the gyro outputs all centered around 390 (when sitting still)? I thought this was a bit odd, but it is also stated in the datasheet that center voltage for gyros is 1.23v.
    By combining the X outputs from both accel and gyro to my Arduino, I made a weighted complementary filter to control a Segway type ridable bot. It works great!

  • Product WRL-09358 | about 4 years ago

    It works very well as a Serial link between Arduino and PC. Bluesmirf: connect Tx to Arduino D0, and Rx to Arduino D1 - also +5v and GND. Make sure serial speed is set to 115,200bps in Arduino sketch (I could not get it to work at any other speed).
    All that is needed is a bluetooth adapter for PC, I use Blueman in Ubuntu linux to connect Bluesmirf as a Serial device - rfcomm0 on my machine. Then open a terminal and type the following to see the serial readings:
    $screen /dev/rfcomm0 115200
    Setup takes about 5 mins from opening package to reading serial monitor wirelessly.

  • Product SEN-00639 | about 4 years ago

    I personally prefer this company because they put the Jesus 1st fish and cross logo. I hardly call a barely-visible logo pushing religion, but to each his own.
    They also have a far superior product to the Parallax ping sensors, which require that you change the state of the pin from an Output to send the pulse, back to an Input to read it again after waiting for it to return. This causes much un-needed overhead for your code which is avoided by the Maxbotics sensors.
    I have the PVC outdoor model from here and love it. I plan to buy several more of the EZ-1 models.

  • Product COM-09482 | about 4 years ago

    I have a question, How might you display the number “20”? I am playing with this thing and… basically if you create a 7-segment number on more than 1 of the 4 digits, it will display the same 7 segments on each digit.
    I can make a 2 appear on digit 3, and a 0 appear on digit 4… but try to do them at the same time and I get an “88"
    am I missing something?

No public wish lists :(