nickey

Sounds good to me.. thats the way I will keep it, with no resistors.. Thanks Rob

Ok, that just created a new question. I measured 178ma through the relay coil when activated and so I came up with a calculated 68 ohms for a collector resistor.. but when I put it in the circuit, the relay wouldn't trip any more.. I had to drop down to a 22 ohm resistor before it would engage, and after only a few seconds the resistor (1/4 watt) gets very hot.. don't think that will work well when the pump is on for 5 or 10 minutes at a time.

Thanks for both of your answers, that helps a lot. I will implement your suggested changes.

In examining my fish tank aerator circuit, I am uncertain about the use and value of a couple of resistors. (I acknowledge I am a tinkerer and not an EE).. 1. What is the purpose of R2? is it needed? (I copied its use from a different relay driver circuit) 2. Though they both seem to do the job, how would I calculate the correct values of them? (I just started with them first as is) thanks water pump relay.doc

Thanks for the comments, no I haven't looked at overall power consumption yet.. good idea though. My current thoughts are that since I control the on and off times that I can keep the battery drain to negligible. Might look at your suggestion in the future though.

thanks Rob, those look great, I just ordered some samples from TI.

hi Mike, wow thats just what I was looking for.. My only experience with micro controllers is the TI MSP430 and so I have no knowledge of the PIC systems.. Did it take much programming on your part? Also did that chip allow you to drive a relay directly from one of the pins? My relay has a coil taking about 200ma to activate it so I had to use a transistor.

RobG, thanks for the info on choices other than LM317. I looked at TI and then LT at their stepdown converters, but unless I am reading them wrong, they all seem to be packaged for surface mount. I don't have that kind of accuracy in my tinkering space and so unless they also have some with nice big pins on them I don't know if I can ever use them.

Thanks zeke for the nice pointer to all the relay circuits.. I actually ended up copying one of them for my circuit (now posted in projects). As for mystboy and optocupler, thanks for the idea but it looks like I have found a solution with the parts I have on hand.

Ok, thanks to all of the great help I've had on this forum, I have this working on my breadboard and would love to hear any comments or criticism that could help me turn it into a better circuit or better coding. Warn you in advance that my circuit layout and C++ structure is far from professional. //*************************************************************************************** // Fish tank aerator // final version 1.0 // April 2011 // Built with Code Composer Studio v4 //*************************************************************************************** #include

thanks, I have the voltage reg working now.. used an LM317 circuit.

On my current project I am trying to get the MSP430G2211 to turn on a 12 volt pump for a certain duration. I have all the other logic and coding worked out and done, but I am at an intersection as to how to convert the 3v out signal to control the pump. (see diagram attached).. Do I use some transistor to hit a Power MOSFET (I have an IRF510) and then use that to activate the relay (not sure on how to configure that).. Or do I use the IRF510 or something similar instead of a relay? (never used a MOSFET for anything before).. Or perhaps a better idea yet? thanks.. water pump.doc

infrared, thanks for the interest.. I am making a "live-well aerator control system" for my fishing boat. When I take my boat to Minnesota each year (where I grew up) one of the more popular baits are a variety of live minnows. When I am up at a lake for a couple of weeks, the tendency is to leave the minnows in the boat's live tank overnight along with any late caught fish that I didn't want to clean that night. Rather than leave the tank pump on all night and drain my boat battery, I wanted a way to have the pump come on at selectable times and durations. I first looked at timer chips a

Thanks Geekdoc, I'm sure there are a few of us old players around. My continued amazement is how fast the industry grew and how complex computers are now in everyone's hands including 2 year olds. Its fun to have a circuit and program development environment back in my hands. I'm looking forward to finding new things to make. Before I came to micro-controllers recently, I made lighthouse (to scale) replicas out of wood and mounted on stone and then made an internal battery powered circuit with an LED to simulate a beacon light fading on and off to look like it was rotating.. Then I made a

Thanks for the note about the thumbs up.. I was wondering how that worked.

Great reply... just what I needed.. going to go try it right now. thanks!

I've already posted a few questions and have been getting some really good help back. Thanks. I have a long history in computers and programming (I go back to the days of paper-tape and punched card decks if any of you can comprehend that)... then I spent the last majority of my career in management, so my brain is pretty well 'fried'. I am having to learn C++ from scratch, but my logic reasoning is still intact. I also like to play with discrete circuits which is what led me to micro-controllers since you can do more with less complexity. Just a tinkerer now and making things for my o

OK, I have debugged my code on the Launchpad and I like it and am ready to move the MSP430 to my own breadboard for further testing and final development. Question I have is "Is there anything different I should be doing when downloading my program to the chip?" When I download in debug mode I just hit the debug button and it compiles and then downloads. Is there extra and unnecessary code loaded while doing this? Is there a different method for downloading non-debug code for final use? I scanned through the help documents but couldn't find a reference to something like this. thank

Thanks Zeke, thats exactly what I needed to know.

Just started to build my C program (but don't have my LaunchPad yet) and I have 2 questions please: 1. how can I determine what the final downloadable object code is so I can be sure it will fit onto the u-cont? 2. how do I get rid of the error "warning: last line of file ends without a newline"? thanks

thanks, that helps to clear up my understanding...

I was reading a separate post about the new TI chip coming out (this forum) and the author stated "Three timers with 4 CCRs each (finally, enough timer to do what I want!) Timer C will be 32-bit and will have 8 CCRs (sweet!)" I am a little slow here and don't fully grasp the significance of these parameters. How does increased number of CCRs benefit me? What can I do with them for example? I'm still early in my experience with C and the MSP430 so it just hasn't sunk in yet. thanks

Thanks for the reply, and you are right, I am working on my C program right now. I haven't decided whether to poll or not, timing is not critical nor is power consumption so which ever is easiest will probably work. I have already ordered a sample of an LTC3388EMSE-1#PBF from Linear since it sounded like it would do the job good for a regulator. I have found and collected a bunch of C++ coding examples and I plan on stealing a little code from where ever I can and piece together something and then start testing. thanks again

I know some of you C experts out there could whip up a sample program for my new project in probably minutes, even if not perfect I could use my limited skills to test and refine it. I just ordered the Launchpad and hope to make a special application board. First of all I am much better at circuit soldering and debugging than I am at coding (very inexperienced, especially C++).. If I had some examples I could work with them and expand them I think. Its all the necessary setups and interrupts and such that I need to get past. What I want one of the 'included' msp430's to do is Read two