Post Created date
led_display_using_transistor
Can you post the schematic of what you're using, and the source code for the microcontroller.
Friday, 30 November 2012 - 18:46
Problems with PWM and CNY17-3
What's limiting the current out from the uP pin when it goes high? A better way to hook up that part of the circuit would be to connect the cathode of the optocoupler LED to the...
Thursday, 29 November 2012 - 16:33
led_display_using_transistor
What exactly do you mean by using transistors? typically a dot-matrix LED is arranged in row/column format, where each row of LEDs might have all the anodes in a given row...
Thursday, 29 November 2012 - 15:30
PCF8574 I2c port extender current sink always sinking proble
You lucked out on this circuit. The data sheet for the PCF8574 says that the maximum voltage you can apply to an output pin is Vcc +0.5, or 5.5V then down in the fine print it...
Tuesday, 20 November 2012 - 15:46
74*165 vs 74*166
On the 74*165, parallel data loads asynchronously as soon as the LD signal goes low, regardless of the state of the clock. On the 74*166, the parallel load is synchronized to the...
Tuesday, 20 November 2012 - 15:23
Where to buy electromagnet
For those that are curious: http://www.rfcafe.com/references... #28 awg copper wire weighs 0.4837 lbs/1000 feet, and has a resistance of 70.8 ohms/1000 feet @ 25 degrees C 48 ohms...
Tuesday, 20 November 2012 - 14:48
enc28j60 - no connection with ethernet
If L1 was getting hot, and the replaced chip didn't fix the problem, I suspect that the transformer inside the RJ-45 connector is bad.
Friday, 26 October 2012 - 17:47
snap-action thermostat
We'd need to know a whole lot more about the thermostat before we could give you any answer that's much better than a guess. The make and model would be a good start. Just as a...
Thursday, 25 October 2012 - 19:49
Compact Flash GPS Interface
One other thing to be aware of if it's a really old GPS unit. The GPS signal contains a 10 bit field for week number, and that field overflowed on August 21, 1999. If the GPS was...
Wednesday, 24 October 2012 - 12:14
What type of sensor for this task
Is contact with the liquid permitted? If so, a float valve of some sort might be the easiest solution.
Thursday, 27 September 2012 - 18:44
Light sensor for Long cable run
Why not use a small processor like the ATtiny85 at the sensor to read the sensor and communicate back to the main processor using something like RS-485.
Thursday, 27 September 2012 - 14:29
Sync between multiple identical devices
if you just need the devices in synch without any specific timing requirements then try this technique. Each device sets the pin low, then goes off and does whatever operations...
Thursday, 13 September 2012 - 21:39

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