Member Since: March 10, 2010

Country: United States

  • Arggh I wish I read this two weeks ago. I Eagled up a four channel version of this thing so I can run four 10W LED modules (for an RGBW) at 1A (peak) each, as part of a strobey party light setup. Fortunately I could fudge a little 0603 10k between the pins 2 and 3 on the AL8805s and get startup under control. But I will have to do a revision 2. My retinas are still crying.

    I am imagining the uC disconnecting from the board by accident and letting it run full speed till something catches fire in the beam. Definitely need pull-downs integrated with the board.

  • Ive tried doing that a couple times too and my wires eventually broke off the jumper pads. I didn’t like the dangling switch either.

    I think one of the lessons we are supposed to get from SFE is to take what they give us and run with it. I modified their SFE eagle file to include a DPDT SMD slide switch and a couple leds to indicate voltage (red-5v green-3v3). My FT231x board does exactly what I want it to.

  • Polycase has the correct case. Soldering the small components can be difficult but it is also completely doable with hot air or a toaster oven. The hardest part for me was getting 0.031" boards made that were both reasonably priced and decent quality. Quotes were from $3 to $100 per board. Ended up getting cheap boards and they are extra delicate during assembly (from heat).

    I updated the SFE design to include a couple LEDs for feedback (tx and ack) and changed the mcu. Using the slightly transparent cases from polycase and the LEDs are very nicely visible through the case. Seems to work just fine.

    You should just make some.

  • SFE still provides us the FOB eagle files and avr firmware and all of the components are available (from others). You should make a couple yourself. They cost around $20 in parts if you do yourself. QFNs are not that hard to solder.

    I have several FOBs and still (in 2015) use em and need more. Ive made several more. I sure wish they werent discontinued.

  • I bought one of these in 2011. It never worked quite right and i cant remember successfully loading code to a single board with it. I forget every few months and take it out to try to program something and nope it doesnt work and put it back. Ive sneered at it for four years, thinking how it was a total waste of $20.

    Just this week i thought up a project that could use less pins than the atmega32u4 but still wanted usb, and remembered i had this. I threw some code together in the AVR Studio and loaded it with my pocket programmer and WOOOO, it has finally been useful!

  • 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.

No public wish lists :(