kwan3217

Member Since: April 6, 2009

Country: United States

  • News - AVC 2014: Bots, Copters, … | about 2 months ago

    I note that the Micro/PBR class says either fits within a small bounding box OR costs less than $350. I am planning a robot which doesn’t fit within the box, but new parts for it will be considerably less than the price limit, but only because I have a ton of Arduinos and other parts lying on my bench from other projects. How does that work? Should I count the cost of those other parts, even though they weren’t purchased for this robot? Should I even try to get in the Micro class? I ask because I want to maximize my chance of winning, therefore I want to be in the class with the smallest number of members.

  • News - September Caption Contest | about 7 months ago

    That new guy just doesn’t fit in. He needs a hat and beads.

  • Product DEV-10999 | last year

    I was finally able to get this part to work after quite a bit of difficulty by following some tips I have seen elsewhere. My notes in case it helps someone else.

    Environment: Windows 7 64 bit Arduino 1.0.5

    Get the driver zip mentioned in the “Getting Started Guide”. Copy the single file within it to c:\windows\inf, it will ask for administrator permission to do so.

    From the same page, get the Arduino addon files and install them as instructed. Start Arduino, go to File/Preferences and turn on “Show verbose output for: ” for both compilation and upload.

    Connect a jumper wire to one of the gnd pins and be ready to touch the other end to the rst pin. For me, I just slid the end of the jumper wire into the gnd hole and held it in place diagonally so it was touching, then touched the other end to the rst hole as needed.

    I did this first, but I don’t know if it is necessary. I plugged the board into USB, heard the USB connect bing (low note followed by high), then about 7 seconds later, got a USB malfunction message and a USB disconnect bing (high note followed by low). During that 7 seconds, the part was recognized in the Device Manager as a Sparkfun Pro Micro.

    Now for the final step: Start Arduino, select Sparkfun Pro Micro 3.3V, and double-tap the reset pin. During the 7 seconds, you should be able to select the correct serial port in Tools/Serial port. Now load an example sketch, I selected File/Examples/04.Communication/ASCIITable which just uses the USB serial port, no other hardware or D13 light needed. Push the upload button, then watch the status window. It will do something to the effect of

    PORTS {COM7, } / {COM7, } => {} PORTS {COM7, } / {COM7, } => {} PORTS {COM7, } / {COM7, } => {}

    a lot, maybe 15-20 times in about 4-5 seconds. Towards the end of that time, double-tap the reset pin. If it works, avrdude will print a lot of text, report success, and the part will work normally from then on. Too late on the double-tap and it will not find the device, too early and the 7-second window will expire before avrdude gets into contact with the bootloader and holds the window open.

    Here’s what I think is happening: I have seen notes on the net to the effect that a poorly behaving sketch can effectively crash or block the USB driver in the device, and never let the bootloader do its work. The reset double-tap forces the bootloader to start, wait 7 seconds before starting the user sketch, and if Arduino starts a sketch upload during that time, then things work normally. Outside of that window the broken user sketch blocks things. So, the question then becomes, how did a bad sketch get into the part in the first place? I had this trouble with a part fresh from Sparkfun, which I had never put a sketch on.

    Hope this helps someone out there…

  • News - Your April Caption Contes… | last year

    Visitor Parking Only - All other cars will be destroyed by tiny robots

  • News - Your March Caption Contes… | about a year ago

    Bunk desks have proven to be a great success. Now we just need some bunk chairs.

  • Product WIG-10216 | about 2 years ago

    In a blatant attempt to get readers to my blog, I direct your attention to here . The firmware is now more than halfway done, it actually works. Go to this blog entry, get the links to the new firmware there. Use the bootloader tutorial to find out how to get the USB bootloader onto your Logomatic.

    Sparkfun guys: You are welcome to examine this code, and if it meets your approval, use it on future production runs of the Logomatic.

  • Product RTL-09876 | about 3 years ago

    Found it again - on a comment by another customer:
    Battery protector - DW01
    This says that the overdischarge protection kicks in at 2.4 plus or minus 0.1V, and reactivates once the battery is charged up to 3.0V.

  • Product RTL-09876 | about 3 years ago

    Unfortunately I don’t have the part number for the battery protection circuit any more. Caution: doing this may void your warranty, but thats what Sparkfun customers do anyway, right? You can carefully peel back the yellow tape, then the masking tape underneath, to reveal a small circuit board with the battery soldered to one pair of terminals and the red and black wires to the other. There is one (or maybe two, I don’t remember now) chips on that board, in addition to the various passive components. I was able to read the part numbers and type them into Google. One of the hits was for a LiPo control circuit.
    If you are careful, you can re-wrap the tape and keep using the battery with no trouble afterwards. Just don’t flex the metal tabs connecting the battery and board too much.

  • Product RTL-09876 | about 3 years ago

    I opened up the yellow tape on one of my batteries to try and find the answer to this. The one I opened up was a 1100mAh from Sparkfun. I presume all the other sizes of batteries come from the same manufacturer. There is a battery protection circuit on this battery, and one of its functions is to protect against overdischarge. If I recall correctly, it cuts out when the battery voltage gets down to 2.5V, and re-enables when the voltage gets back above 2.75V. These are lower numbers than I have heard (around 3V minimum) but I have let these things discharge with no extra protection other than what’s under the yellow tape, with no explosions, no physical changes to the battery at all (heating, bulging, etc) and no apparent loss of life. I have yet to need to withdraw a battery from service due to overdischarge or any other reason, and some of my batteries are two years old.

  • Product SEN-10530 | about 3 years ago

    Has anyone had any capacitor problems like with the early HMC5843 boards? Did Sparkfun do anything special with the caps on these ones, or are they ordinary garden-variety caps?

No public wish lists :(