555 countdown timer design question

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  • Dannyx
    replied
    Re: 555 countdown timer design question

    Well it's not really black, but sure It's this. Still, I wanted to keep it as simple as possible, so I'll push on with the serial method since ISP seems tough to achieve with the arduino IDE...or at least I THINK so.

    Back to that cap you asked about: should it go between RST and GND or something ? This programmer doesn't have a RST pin so I'm guessing that's the issue....

    Leave a comment:


  • stj
    replied
    Re: 555 countdown timer design question

    Originally posted by Dannyx
    Dumb question, but if they don't work for the purpose of programming the arduino, what are the MISO/MOSI etc pins on the CH341 adapter for ?
    oh, you have the black eeprom programmer?
    yes, that can do isp - if you use the right software.
    (or maybe avrdude does that hardware - never looked!)

    Leave a comment:


  • Dannyx
    replied
    Re: 555 countdown timer design question

    The schematic you posted also confirms I got the pinning right: TX to RX and vice versa, instead of RX to RX etc.

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  • Dannyx
    replied
    Re: 555 countdown timer design question

    Originally posted by stj
    isp needs a dedicated programmer - preferably a USBasp
    Dumb question, but if they don't work for the purpose of programming the arduino, what are the MISO/MOSI etc pins on the CH341 adapter for ?

    Caps ? Yeah I do (that would be 0.1uF right ? I suck at these )...I knew it from the start there's something fishy about that reset pin and even read something along those lines....

    Yes, no question about it - that CH341 "crap" helped me a lot in the past years, ever since I became more confident in using it and discovered it can do many other things besides programming SPI chips (which might actually answer my first question right there), so I too didn't agree with him.

    Leave a comment:


  • stj
    replied
    Re: 555 countdown timer design question

    btw, the ch341 adapters/chips are the best IMO, so tell your m8 to fuckoff!

    Leave a comment:


  • stj
    replied
    Re: 555 countdown timer design question

    isp needs a dedicated programmer - preferably a USBasp

    i can tell you why your second upload failed,
    on a full arduino the reset pin on the atmel is linked to a handshake line on the serial port/chip so the software can reset the atmel into it's bootloader.
    can you dig out a 100n film cap?
    Attached Files

    Leave a comment:


  • Dannyx
    replied
    Re: 555 countdown timer design question

    Same thing happened just now: it decided to upload once again...I still don't know what gets it going...I even tried replacing the wires with a shorter piece (shielded even) but made no difference.

    My mate suggested the CH341 adapter is crap.....

    Guess I'll also try with the MISO MOSI CSK pins.....I believe it's called ISP ?

    Leave a comment:


  • Dannyx
    replied
    Re: 555 countdown timer design question

    I did manage to get it to upload one sketch, by some sort of luck....and I say that because I thought I got it going and the problem got solved (I selected ProMini in the menu), but then when I tried uploading another one, I got "programmer not responding" again, even though I touched no-bloody-thing....the wires going from the arduino to the CH341 thing are about 20cm long...could that be too much and cause spotty functionality ?

    Leave a comment:


  • stj
    replied
    Re: 555 countdown timer design question

    let the reset float - it should have a pullup on the board, connect tx,rx & ground and make sure the arduino software is set to use the right comport.
    try swapping tx and rx if it's not getting anywhere

    Leave a comment:


  • Dannyx
    replied
    Re: 555 countdown timer design question

    Finally back on this project and I'm having some issues: can't get my CH341 programmer to work with the damn thing and the information you get online is disappointing if anything: not nearly thorough enough to get a beginner up and running, as it's missing some important details, which may seem self explanatory to some, but others, myself included have some questions.
    I'm using a CH341 interface which I normally use for programming TV SPIs. I HAVE used it as a serial COM port before, when I connected it to a TP Link router to try and unbrick it, so I KNOW the adapter works for that purpose. I think I'm doing something wrong on the Arduino's side: I connected TX to RX and vice versa between the two boards, as well as GND of course, but I get an error saying |Not in sync" after 10 upload attempts. I'm not sure I got my arduino software configured properly...aside from obviously selecting "arduino mini" and the correct COM port corresponding to the serial programmer, I can't see too many other options like I did when I messed around with that router where I had to also set the baud rate and flow control.

    Another slight mystery is that reset pin of the mini...what should I do with it ? Let it float or use a 0.1uF cap between it and GND ? Does the board need to be put into some sort of "programming mode" or it just works at any point, even if the sketch already on the arduino is running ? Again, the info is not thorough enough on this....

    This SHOULD still work right ?! I don't see much difference between my adapter and others demonstrated online...a little help pls ?
    Last edited by Dannyx; 12-06-2017, 07:04 AM.

    Leave a comment:


  • Dannyx
    replied
    Re: 555 countdown timer design question

    Originally posted by stj
    what does it say on the crystal?
    3.3v models only run at 8MHz, while 5v ones run at 16MHz
    Says 16000 on the crystal, so I believe it should be a 5 volter.....just made up a new word apparently

    Leave a comment:


  • stj
    replied
    Re: 555 countdown timer design question

    what does it say on the crystal?
    3.3v models only run at 8MHz, while 5v ones run at 16MHz

    Leave a comment:


  • Dannyx
    replied
    Re: 555 countdown timer design question

    My Mini just arrived today and it works, but I'm not sure about its operating voltage: while I specifically asked for a 5v model when I bought it, I'm not entirely sure I really got the 5v model in the end. I applied 5v to the RAW pin and it came on just fine, but I only get 3.3v on the VCC pin....the regulator says L05 so the data is contradicting. I guess one sure way to find out is to define a pin as high and measure the output....

    Leave a comment:


  • Dannyx
    replied
    Re: 555 countdown timer design question

    Originally posted by budm
    Since it is not isolated power supply I would be really careful when hooking up PC or what ever you will need. I would go with isolated power supply for safety concern.
    True that. Power pack/wall wart, whatever you call it, seems to be the way to go.

    Leave a comment:


  • budm
    replied
    Re: 555 countdown timer design question

    Since it is not isolated power supply I would be really careful when hooking up PC or what ever you will need. I would go with isolated power supply for safety concern.

    Leave a comment:


  • Dannyx
    replied
    Re: 555 countdown timer design question

    Quick look at how the power supply for this thing is gonna look I suppose: interestingly, I was expecting the remote module to have a capacitor dropper like most cheap and cheerful China products tend to have, but it's actually got a tasty little switch mode power supply, operating in what appears to be a buck configuration, though there's no isolation as far as I can tell (notice the GND trace is common between the primary cap and the green secondary cap).

    There's an unmarked switching regulator, a coil, a diode, two feedback resistors and that takes care of the 12v section. It's a cascading supply, meaning there's an additional 5v supply derived from the 12v one via a small 7805 regulator. It's this 5v supply I'm interested in: trying to keep the project as small as possible (so I could preferably tuck inside the light itself, though it's not a requirement), I'm not too sure whether it's better/safer to stick with this PSU to also power my arduino or to use an off-the shelf power brick....I could lower the part count even further by dropping the primary voltage straight to 5v by messing with those feedback resistors so I can eliminate the 7805 entirely....I'd probably add a varistor because I'm not liking the idea of letting my arduino "ride the live wire" like that with no protection whatsoever.....
    Attached Files

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  • stj
    replied
    Re: 555 countdown timer design question

    so dont.

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  • eccerr0r
    replied
    Re: 555 countdown timer design question

    But...but... I've been working with this over a decade and never needed it!

    Leave a comment:


  • stj
    replied
    Re: 555 countdown timer design question

    so fix it, you have the source there.

    Leave a comment:


  • eccerr0r
    replied
    Re: 555 countdown timer design question

    Looks like this was after when I started with AVRs... no 90S2313 and 90S4433 support... they do support the similar Tiny2313 and Mega8 but they're not quite the same.

    Leave a comment:

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