mwwalk

Member Since: August 4, 2010

Country: United States

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www.TheWanderingEngineer.com

  • The easiest thing to do would be to use a knife to cut the small trace between the center pad and the 500mA pad. Then get a regular through hole resister and solder it into the “prog” space between the two JST connectors. Page 7 of the datasheet has a chart showing which resister to use to achieve a given output current. For 60 mA, you should use a 16k resister.

  • From the board, it looks like the battery in and system out are connected and just have different labels on them but could be used for either. Would somebody confirm that I’m not reading that wrong?

  • I would also really love to know the answer to this. I’m considering writing a lab manual for a class I teach and I have no idea what software to use. Should I go with simple Microsoft Word or the really advanced inDesign. Or should I do without wysiwyg and use Tex and just deal with having less control on images? Would love to know what you used Derek.

  • I love this little display! I wanted to be able to create images for it but nothing I saw did exactly what I wanted. So I wrote a processing sketch that creates 84x48 squares on the screen and allows you to click to turn them on or off. Also has buttons to invert, move up/down/left/right, and flip horizontally/vertically. Then, it saves the hex data to a text file to copy to your code. You can also load an image (any size, any colors) and it will scale it, convert to b/w, then put it in the rest of the program so that you can alter the pixels or move it. It isn’t perfect for every occasion but I’ve found it useful and I hope others might too. It is heavily commented so it should be easy to figure things out and change them if you want something different. http://thewanderingengineer.com/2014/07/12/nokia-5110-screen-photo-to-bitmap-converter/

  • Yeh, I don’t actually care about what the thread was supposed to be vs what is actually is. I just want to know, if I order a m14 tap, will that work?

  • Probably a dumb question but here goes… If I’ve made a shield using this kind of logic level converter to go form 5v on an arduino to 3.3v, what happens if I put it into a 3.3V arduino so that it is now going from 3.3V to 3.3V? Will it still function or just stop working?

  • Well today I tried to change the 900MHz to another speed again and it worked just fine. Not sure if the earlier problem was mine, the wiring, the terminal I was using, or just some upset electronics gods. But it works now so I’m very happy. I wrote a simple sketch to try and measure the range. One arduino sends a number to another arduino which then replys back to the original arduino all over these xbees. I was able to get about 300 yards on ground level but that also included lots of power lines and buildings and trees so I’d image it’d work better under ideal conditions.

  • I’m just curious why the similar part from Adafruit is so much less expensive. 1.95 vs 4.95.

  • I used one of these following the bildr tutorial on an arduino and it worked fine, but when I tried to use it on an ATtiny, I ran into problems. Turning the knob didn’t adjust the value at all, though at least there was no change when I wasn’t moving it. I can’t for the life of me figure out why. The ATtiny is operating at slightly slower speed (8MHz as opposed to 16MHz) but should be more than enough when all it’s doing is checking an encoder. The first thing I suspected was that the Software Serial was causing problems. So I took it out and used an led to represent the turning. Still didn’t fix it. I originally had the software serial tx pin as digital pin 2 on the ATtiny (using pins 0,1 for encoder). I thought maybe this was causing problems so I moved it to pin 4. It started to work better but not near as well as when it was on the arduino. It moved very very slowly when I turned the knob; maybe +- four values for a full rotation. The next thing I tried was changing the bildr code since it declared variables every time it went through the ISR (Interrupt Service Routine) loop. I moved the declarations outside the loop but that didn’t help anything. The final thing I did was to get rid of the interrupts and just have it check the status of the encoder pins every time it went through the loop. After this it worked perfectly, even when I moved the Software Serial back to pin 2. So I still don’t know what the problem was, but I know it works this way. The only real downside for me is that you can’t use any kind of delay in the loop because it may miss part of the encoder turn. If anybody can tell me what my problem was or has had similar experiences, please leave me a comment. You can view a more detailed description here: http://thewanderingengineer.com/2013/05/05/rotary-encoder-with-the-attiny85/

  • OK, I just answered my own question so I thought I’d reply here. I was mistakenly adding a “k” into the baud rate thinking that 9600bps was actually 9600kbps. So the answer is, at speeds less than 156kbps, the baud rate is the limiting factor, not the speed of the radio transmission.

No public wish lists :(