low pass filter for arduino PWM control to reach 10V Analog control

Arduino PWM control frequency is about 488Hz for pin 3,9,10,11..
and 977Hz for P5,6, in order to make it analog out put.
we selected a low pass RC filter where R=4.7K, C=3.3uF, which result a cut off frequency at about 10Hz...response time about 0.1-0.2 sec.

then we need to amplify it to 10V
http://arduino.cc/forum/index.php/topic,12135.0.html

2 ways are considered:
lpf 5v pwm and switch up tp 10V
http://www.3reef.com/forums/i-made/arduino-pwm-0-5v-0-10v-121705.html




using 10V source and MOSFET then lpf
http://www.reefcentral.com/forums/showthread.php?t=1995554

留言

張貼留言

這個網誌中的熱門文章

AIS0. understanding AIS NMEA 0183: How it's coded

For my boat tracking system, I found out that using AIS format seems to be a good idea, at least I don't have to worry about how to present boat data, since there are already plenty things for do this on mobile phone or PC. Here is what I read: http://catb.org/gpsd/AIVDM.html Looking into AIS NMEA0183, it has much more application then I think. Such as MOB device, epir, aid to navigation device...etc, all are included. it use the first few char to indicate the function: Table 1. AIS talker IDs !AB NMEA 4.0 Base AIS station !AD MMEA 4.0 Dependent AIS Base Station !AI Mobile AIS station !AN NMEA 4.0 Aid to Navigation AIS station !AR NMEA 4.0 AIS Receiving Station !AS NMEA 4.0 Limited Base Station !AT NMEA 4.0 AIS Transmitting Station !AX NMEA 4.0 Repeater AIS station !BS Base AIS station (deprecated in NMEA 4.0) !SA NMEA 4.0 Physical Shore AIS Station It can also be used between device on boat for message communication, AIVDO The...
閱讀完整內容

GeoSetter how to add geotag on to pictures, and export to google earth as kmz

圖片
I use gps info of my cell phone when I take pictures, so that I can find where these pics were taken after a long voyage. I also wish to export these pics to google earth or google map, which can be kml or kmz. https://geosetter.de/en/download-en/ Geo setter is a very powerful one. Some times my phone was not able to add geotag info on the the picture, since it does not have location info at that time(indoor picture or gps was not available). Of course you can edit the pic, but geo sitter provide a better interface, you can pic a location on map and then assign the location to the photo that you selected. much easier than deal with coordinates. I notes the steps as following. After install geosetter, select the folder where you store your images. photos with a blue location dot means these pics contain geotag. select one pic with no blue dot, and go to top menu "map", select "show overview map"  a google map will show up with goe location of pictures...
閱讀完整內容

Measuring current and voltage using 3DR power module and arduino

圖片
I used to use Allegro ASC current sensor like this one. since it's calibration free, and out put voltage according to voltage. But these sensors are not easy to get in taiwan, and quite expensive. As APM is popular, the 3dr power module comes with different source, good price, with 5V supply on it. this one should be handly.  while saying it's open source, I'm not quite sure where to get the code today. But a good source from sparkfun comes out form googling. it's a attopilot voltage and acurrent sensor breakout, there are 90A and 180A versions. https://www.sparkfun.com/products/9028 Both are constructed with a shun resistor and a TI INA-169, which will out put a current based on the voltage difference on both side of shun resistor. Crossing this current through a resistor which connect to ground, then we have a voltage on this resistor, which is in function with the current. As to voltage, there is a set of dividing voltage. The good t...
閱讀完整內容