I'm trying to design a pulse counter and frequency to voltage converter, both use the same pulse, which is variable, to determince when to trigger another circuit that will turn off SSR. This SSR will be triggered by a momentary switch to turn on & needs to turn off when either 730 pulses have been received if the pulse train is less than .
8 pulses/second or 10 seconds after the pulse train is pulsing at or faster than .8 pulses/second (which ever comes first). I've thought of using a synchronus counter feeding an AND gate for pulse counter The other a freq to voltage converter that triggers a voltage comparator that then feeds a 555 10 second timer. This circuit needs to be able to be stopped with a seperate momentary switch.
I'd like to be able to do it with lots less components like a microcontroller, but I've never designed & programmed one of these. Can anyone enlighten on this & the best place to find info?
What if the pulse train changes rate during the analysis? Are you sure you stated your requirement correctly? I'm reading that if the pulse train is slow (=8 pulses/sec) turn off the SSR after 10 seconds. Is that correct?
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is a good book for the 18F series of PIC micros, but it may be a bit too terse for someone starting out. It comes with a circuit board for a development platform and digikey sells a complete kit of parts to flesh it out, but you will need to get the PIC flashes somewhere. After it has been flashed, then you use an internal boot loader to reprogram it.
I don't use a dev board per se, I just tinker on solderless breadboards. For flashing the PICs, I use an MELABS USB programmer. It works great and will program many different parts, plus it's fast.
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has a great mailing list with many professional PIC programmers willing to help newbies, just read the rules before posting. Sounds like you don't just want this done by someone else and then handed to you (good :-) I would be willing to help you out on your code whenever I have some spare time, but I normally do 14 bit PICs (16Fxxx series). For someone just starting out, the 18F line may be a better choice, especially if you want to program in C. I know a little about the 18F line, but I've never really played with them.
"Rick" schreef in bericht news: snipped-for-privacy@a75g2000cwd.googlegroups.com...
You did not describe your problem good enough, at least not to me. For a pulse rate of less then .8p/s it will take over 15 minutes to count 730 pulses. Is that really what you mean? Maybe you'd better give some background information as well.
BTW. The "classic" frequency to voltage converter uses a no-retriggerable monostable to produce uniform pulses and integrated them to produce the voltage.
Sorry for the confusion - Also, my info was flawed. The pulse trains should be either < 74 or >/= 74 pulses per second. If the pulses are below 74 pps & then gets to 74 pps, the 730 pulses would probably be reached prior to the copmletion of the 10 second delay that is triggered by the >74 pps. Which ever one gets there first will trigger the reset to OFF condition.
A momentary switch triggers a 555 circuit to (toggle) open & close a SSR at 1 cps & also enables the f/v & p/c circuits. When any of 3 conditions are met, the 555 is then reset which disables the SSR. The third condition is a different momentary switch for a manual OFF.
Another FYI, its been 28 years since I was in school & actually did any real design, so I may struggle a bit in designing this thing. I have a good handle on troubleshooting & knowledge of how these things work when already built, but designing is another story & will take a re-learning curve. Thanks, Rick
"Rick" schreef in bericht news: snipped-for-privacy@m58g2000cwm.googlegroups.com...
All components you need are in the schematic below. You don't even need the
555. The transistor and its related resistors are only necessary if the load is to heavy to be driven by a PIC. A 555 can handle higher voltages and more current then a PIC.
But... That's not the whole story. You will need the datasheet of the PIC12F629 and a software development system. Both are can be downloaded for free from Microchip. You also need a programmer. Several types are for sale. More designs are free downloadable. One that works for me:
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So far the easy part. Then you need to write the software which is quite a challenge and has it's learning curve. IMHO it's worth the effort only if you want to do more with PICs in the future. Be aware that PICs are not the only micros around. You can do the same using a tinyAVR and it's related tools. If I can find the time I'll write some example code tomorrow.
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