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Showing posts from September, 2014

Blast from the past

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MikeM sent this photo he took of the guts of the revolutionary-at the-time Sinclair Black watch beside the Bubble clock shield . Mike also noticed odd behaviour of the clock shields (both bubble and OLED ) when powered from the 3.7V LiPo battery (as shown here ). After a while, the RTC returns bogus time. A quick check of the DS1307 datasheet (page 3) confirmed my suspicion: When 5V is applied within normal limits, the device is fully accessible and data can be written and read. When a 3V battery is connected to the device and VCC is below 1.25 x VBAT, reads and writes are inhibited. However, the timekeeping function continues unaffected by the lower input voltage. As VCC falls below VBAT the RAM and timekeeper are switched over to the external power supply (nominal 3.0V DC) at VBAT. Therefore, if one really wants the clock(s) powered from LiPo, a step-up converter must be used. Another solution is to replace the DS1307 with the (almost) pin-to-pin compatible DS1337 . This one does

Detailed presentation on big data hadoop +Hadoop Project Near Duplicate Detection(summer training main)

Adding RF remote control to Wise Clock 4

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Nick asked me once about adding remote control to his mega wise clock, similar to those  pictured here  (or any wise clock that may hang on a wall, for that matter). An obvious way to quickly and easily do this is by wiring the " simple RF M4 receiver " from adafruit to the 3 buttons of the Wise Clock. This 315MHz receiver module works in conjunction with the  4-button keyfob , also from adafruit. Note that the receiver comes in 3 flavors: momentary, toggle and latch. The one that "simulates" the touch buttons is the momentary one, hence the "M4" in the name (momentary, 4 outputs). The schematic I used to connect the receiver module to the Wise Clock board is shown below. I tested it and it works fine. Almost always :) That is, ALWAYS when the display is not plugged in the clock board, NEVER when the display is connected. Which led me to conclude that either the display emits in the 315 MHz band (interfering with the receiver module; which it didn't; I

Presentation on Big Data Hadoop (Summer Training Demo)

HDSP clock mod displays proverbs

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MikeM ported this " proverb clock " to HDSP clock . I did not have a chance to try the code myself yet (I am out of displays at the moment), but he vouches for it: The proverb code is in place and working well.  I created a simple menu,  accessed by pressing the hour and the minute buttons at the same time.  I  have a 12 hour/24 hour selector, brightness selector, and Proverbs on/off  selector. Grahame Marsh's original proverb list was all in upper-case because his VFD  displays only handled upper-case.  I've regenerated the compressed proverb  list after changing it to only capitalize the first letter.  To do more than  that I'd have to proof-read each of the 770 proverbs and find all the proper  nouns to capitalize.  Capitalizing the first letter as a compromise doesn't  look bad.  It helps the eye find the start of the word while the proverb is  scrolling. Mike also 3D-printed this stand, re-scaling to 72% this iPhone dock  from thingiverse. Thanks M