555 countdown timer design question

[Dannyx]

Re: 555 countdown timer design question

Darn, if it were configurable for per-channel latching or momentary, that would simplify things.

Yes I know - I had already thought of how to accomplish that rather easily.
Haven't really looked into how that IC operates, so yes, it seems complicated, just like when I originally started working with the 555, but I eventually got it down....a micro would make things more flexible, albeit the complexity would then lie in the code and not at all in the circuit itself.

[stj]

Re: 555 countdown timer design question

set the module to momentary,
then cut the tracks of the ones you want to latch between the mcu and transistors and put a 74ls/hc74 in series.
if you wire it right, it acts as a latch.

[eccerr0r]

Re: 555 countdown timer design question

.. or the 4027, or the 4013, or ... lots of FF that will work

Oops I just noticed that I drew the wrong FF, it used another IC when the second FF in the 4013 would suffice... bad kicad! :p

[Dannyx]

Re: 555 countdown timer design question

Apparently what my fellow suggested was an Attiny85, just to clarify.

[eccerr0r]

Re: 555 countdown timer design question

most of them will work just fine.

[Dannyx]

Re: 555 countdown timer design question

most of them will work just fine.

Yes, you're right. The application is so basic and simple, prolly any micro will do....it's just a matter of whether they use the same Arduino code I'm "familiar" with...and I put that in quotes because I obviously have very brief knowledge and it's a good opportunity to brush up on my C

[eccerr0r]

Re: 555 countdown timer design question

And dang, the encoding of pseudocode to AVR-C is taking longer than expected... *sigh*

[stj]

Re: 555 countdown timer design question

well if your going the AVR route the programmer is cheaper.
a USBasp is about the same as a decent beer.

[Dannyx]

Re: 555 countdown timer design question

TBH, I think I'll stick to the "lazy" and more convenient arduino Mini route...I already have a CH341 usb to serial adapter I use all the time for TVs so it should be easy to setup.

[eccerr0r]

Re: 555 countdown timer design question

then there's arduino vs baremetal avr.
I've never done arduino before... I just program them directly.
Are PICs tied in with the dev software/hardware? I was quite disheartened when Atmel got bought out by Microchip.

[stj]

Re: 555 countdown timer design question

pic's need a dedicated programmer.
not saying you cant make one - everybody did in the begining - the DAVID TAIT design was common.

software, you can use MPLABX - which is very nice, and free
http://www.microchip.com/mplab/mplab-x-ide

or a 3rd party thing like these:
https://www.mikroe.com/products/#compilers-software <<< not free, but trial is
http://gcbasic.sourceforge.net/Types...index.php/Home <<< free

[stj]

Re: 555 countdown timer design question

just to add,

i'v always used MPLAB,
i tried GreatCow once and made a "blinky" program just to see if it worked - it did.
surprisingly good software actually.

i tried the Mikroe suite but it wouldnt run properly under Linux - so all i can say is it "looks nice"

[eccerr0r]

Re: 555 countdown timer design question

I've only used tavrasm and gcc (and hence also gas) for atmel. My preferred platform is atmel because of gcc. I use uISP with a parallel port SPI interface for chip programming for Atmel. I still have a pile of 90S2313 and 90s4433 I need to burn, along with a few mega8s... Supposedly I also chanced on an Arduino board with a mega328 on it... Might end up reflashing it to something else, and yes that AVRTransistorTester could get targeted to one of these AVRs.

For PIC I've only used the 16C/F84 and 16F627, and only used the Linux gpasm tools... it's a shame if now one is required to use their tools now. I forget what chip programmer design I used, was a serial port chip programmer for PIC, again for Linux.

[stj]

Re: 555 countdown timer design question

that's probably the programmer that's just a couple of transistors and some resistors & diodes.
i build a couple of those for people once.
good for old chips like the 12c508

[Dannyx]

Re: 555 countdown timer design question

Found THIS which comes close to what I'm trying to accomplish. It will require tweaking of course, but gets me in the ballpark....my skills are very rusty, so I'll have to take it step by step by first turning the light on/off with an actual pushbutton, then replace that with the remote module (since it outputs 5v directly), make sure it still works, then slowly try to implement the "hold" feature....

[eccerr0r]

Re: 555 countdown timer design question

Oh good I won't have to finish mine then

Funny, I was debating whether to rip out the serial code from the template I always start with... alas the serial code template eats up a good chunk of the 2K of flash in a '2313

[stj]

Re: 555 countdown timer design question

2k?
if it was a pic you would be using a few hundred bytes at most.
that's the thing about pics, the assembly is compact but the chips arent the most endowed when it comes to timers,uarts etc.

[eccerr0r]

Re: 555 countdown timer design question

It was my own serial template, which is a full CLI for the AVR. That's why it uses a good chunk of space... Since it was a CLI it used a good amount of RAM too (based on the meager amount of RAM in the 2313) to buffer the command line, and all that code needed to process that RAM...

Note that 2K of flash is 1K of instructions (since AVRs are 16-bit instruction, 8-bit data). I think my CLI takes about 512 words or so of instruction memory (thus 1K bytes or so) but I never calculated it, all I know all those strcmps() I had to reduce the compare strings down to save a byte here and there to squeeze it all into memory...

[Dannyx]

Re: 555 countdown timer design question

Another good one here which pretty much nails it and requires even less tweaks. One thing I WILL want to add is a buzzer which gives off a very brief beep when the light is latched on and perhaps lights up an LED as well to know which mode you're in. The only thing it requires is reversing the HIGH/LOW values for the buttons, since my remote output is active HIGH, so it pulls whichever pin I connect it to VCC rather than GND like in the example.

Got my Mini ordered today, so I'm officially into this

[eccerr0r]

Re: 555 countdown timer design question

Always faster to find a solution already made instead of building one yourself!

I had made a mistake in my pseudocode so I gave up on it for now, I thought that the 2313 supported interrupt on both edges but looks like you could only choose one or the other; back to the drawing board... but I guess I don't have to bother. Maybe I should finish anyway because it's something I can burn these arduino-incapable 90s2313s on in case I need similar functionality someday...