555 countdown timer design question

[Dannyx]

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....

[stj]

Re: 555 countdown timer design question

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!)

[Dannyx]

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.

[Dannyx]

Re: 555 countdown timer design question

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.

[stj]

Re: 555 countdown timer design question

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

[stj]

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?

[Dannyx]

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 ?

[Dannyx]

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 ?

[stj]

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

[Dannyx]

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 ?

[Dannyx]

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

Says 16000 on the crystal, so I believe it should be a 5 volter.....just made up a new word apparently

[stj]

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

[Dannyx]

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....

[Dannyx]

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.

True that. Power pack/wall wart, whatever you call it, seems to be the way to go.

[budm]

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.

[Dannyx]

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.....

[stj]

Re: 555 countdown timer design question

so dont.

[eccerr0r]

Re: 555 countdown timer design question

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

[stj]

Re: 555 countdown timer design question

so fix it, you have the source there.

[eccerr0r]

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.