NEW: Learning electronics? Ask your questions on the new Electronics Questions & Answers site hosted by CircuitLab.
Microcontroller Programming » Tech-O-Meter
October 19, 2010 by Earnhardt |
Hi ALL, I’m a newbie to the microcontroller and this site;
I just purchased & got the NerdKits and hope you Gals & Guys could help.
I am looking for a fast and easy way use my nerdKit to get RPM information from a rotating motor shaft and then display it on GLCD.
I was thinking of using a Hall Effect Sensor. Since I am new at this and in the need to get it done quickly anyone have simple Source Code and parts for the circuit design I could use.
Once I get this RPM information to display on the GLCD I could work on changing and trying other things later. |
---|---|
October 19, 2010 by Ralphxyz |
Search the Nerdkit forum for RPM, this has been discussed a lot. Ralph |
October 19, 2010 by hevans (NerdKits Staff) |
Hi Earnhardt, One of my favourite customer projects of all time is the Hamometer described in this forum post. He did pretty much what you are describing, used a hall effect sensor to measure RPMs. Depending on how fast your motor is spinning this might not work though. Humberto |
October 21, 2010 by esoderberg |
Earnhardt, Below are the pertinent sections of code, pulled from a larger program, that I used to determine the RPM and velocity of a wheel. The setup sounds similar to Hamometer. I have two mags 180 degrees out from each other on the wheel shaft with a nearby mounted hall switch that is triggered on or off with each change in N/S polarity i.e. each pass of a magnet. I use an interrupt in the code to note the change from on to off. Timer setup below is from Nerdkits realtime clock. The velocity equation below assumes a .6 meter circumference wheel. The basic equation is v = delta d/ delta t; in below code delta d is .3 meters for each half rev and tt is delta time. The (t - ttlast)/20 part in the denominator of the velocity equation is there because the delta t value (tt) is only recalculated with an interrupt, which won't happen if the wheel stops, so I wanted the calculated velocity to decay to zero with t continuing to grow but with no new tt calculated. The numerator is multiplied by 10000 because my clock (t) is in .1 msec increments. Eric
|
October 25, 2010 by Earnhardt |
Hi All, Sorry for the delay in getting back with any of you. Thanks for all the information it's very helpful, I just finished up on the Temperature Sensor Circuit, and have taken a look at the Hamometer, this is somewhat the path I would like to go but in a bigger scale. Eric thanks for the code I’ll take a look and see if I could get it working. Take a look at the Rechargecar.com. How it works is they have a hall-effect sensor that’s connected to their product called the AutoBlockRPM this device provides power to the sensor and connects to a netbook via USB which they have written a small “exe” that’s is doing the conversion that is installed on the netbook then it outputs the RPM information to a Mimo display. How I know this is by talking with them. What I would like to do is basically the same thing but not use the netbook and use the nerdkit. |
Please log in to post a reply.
Did you know that talking to the microcontroller over the USB/Serial link is easy under Windows, Linux, and OS X? Learn more...
|