Member Since: March 10, 2010

Country: United States

  • Would you believe I just got “got” again?? Grabbed a spare Arduino Pro 5V to do something with a WiFly module and spent several hours trying to figure out why it wont talk through the serial. It was those dang resistors again.

  • I used a TI PCA9548A I2C Switch in a circuit to take care of the address issue with a couple BMP180s that have the same address. It switches the SDA and SCL lines on or off via I2C. The “via I2C” was what sold me. I am already connected to the I2C bus so no extra pins needed. Connect to the sensor, read it, and disconnect. Do again for another sensor with the same address. The other thing connected through the switch is a BlinkM that I am using as an indicator and its sending noise on the I2C bus making other I2C stuff not work. With the I2C switch I can tell it what color pattern to run and then isolate it. The I2C switch also acts as a logic level shifter.

    I was going to use a multiplexer until I found this thing.

  • I totally agree. I just bought one of these a month ago at digikey to program some boards i built that use the soic attiny85. My boards are small and this clip works perfect.

  • Thanks for pointing that out. I think they should make a note up there in the product description. May be obvious to someone but wasn’t to me, and i even read the datasheet: 1. If you have the gain off then normalize by multiplying by 16. 2. If you have the gain on then no adjustment needed.

    I still cant tell if my numbers are correct. I have the sensor in a chicken coop. Nighttime is 0 Lux and Daytime peaks around 60 Lux.

  • Thanks for sharing your code. That got my sensor working.

    I wanted to not use Python3 (just Python2._) so I did a little more looking. Ended up using more direct io code (using io and fcntl) which worked for reading from the HTU21D. So yea, smbus wont work but its not that hard to make your own smbus clone/variant that will work.

    And adding… I just used this same method to read from my AM2315 which also doesnt play with smbus. I bought the HTU21D because I didnt want to deal with another AM2315, and it has the same problem with smbus anyway. Now im reading both in Python2._, and dont have a separate code for just the one sensor.

  • agreed. im using the A0-A5 on a pro mini, using PORTC calls for parallel data output on the entire PORTC. very time/cycles sensitive. i would love to have all six pins available.

    other than that, this looks interesting!

  • What is the purpose of the resistors on D0 and D1 (RX and TX)? These are only on the Pros, and not on the regular Arduinos or the Pro Minis. I have had to remove and jumper them on previous projects. Thanks.

  • Thanks!

    I used your your code for debounce and its working great.

    The solution i posted above from 2010 worked but added too much delay and tended to get annoying when trying to push a button a bunch of times quick. i have removed it and im now using yours.

    all better.

  • Im using this board with an Arduino Pro 5V (DEV-09219).
    In order to get it to work with the Arduino Pro I had to bypass the 1k resistors on the RX and TX lines (D0 and D1) on the Arduino Pro. Im not sure why the resistors are in-line to pins D0 and D1, because they are not in the Regular Arduinos, nor are they on the Pro Minis.
    It worked perfect with my Uno and my Duemilanove.
    Im mentioning it to save some other sucker a few hours of troubleshooting. UGH.

    1. has anyone used one of these as a simple vibration sensor? i need a CHEAP and small sensor to detect movement.
    2. will the internal balls and pins get broken or damaged if this is installed in a dynamic environment? Im talking in dancing shoes…
      I am making adult light up shoes using an attiny and some leds. My gf insists that there has to be a switch of some kind in the circuit and cant be always on. thx.

No public wish lists :(