#81 eBay Goodies Update

[@ronalddhs3726]

Hi Ralph, Thanks for your informative videos. I normally start my projects with an Atmega 8A (£0.60 from eBay) and if the project gets a bit too big for it, then move straight to the 328s (as they the 2 micros I currently stock); your point stands: the 328s are most of the time overkill for our embedded applications. Looking forward to see your next project.

[@RalphBacon]

Hey there "Ray" (I'll call you Ray as Mr Saloman seems a bit formal), I had a look at the ATMega8A chip and it seems very capable indeed. Interesting that you're looking forward to my next video because it is strongly related to your post (but not about the Mega 8A). No spoilers, sorry. Keep tuned though and thanks for the heads up on the Mega 8A chip.

[@Roy_Tellason]

What's the other chip on that 555 module? Rod Elliot (See Elliot Sound Products, out of Australia, an *excellent* electronics site!) has shown that hack with the potentiometer as a way to get a linear pot to act like a logarithmic one. Check his site out.

[@RalphBacon]

Well that's 30 minutes of my life I won't get back again, Roy! I was immediately sucked into Rod's website. Down the rabbit hole I went. Absolutely fascinating. I will be returning often. Yes, the log/linear pot hack is well-known, I guess. I will have to remember to mention this website when I get my preamp.

[@zodak9999b]

Very good video, Ralph. Quite a few of my projects aren't a lot of code, so I like the 168 based modules. I use a lot of various pro minis, and just have a Sparkfun USBSerial adapter that I plug them into for programming. The same adapter plugs into my ATTiny, ESP-8266 and ESP-32 progammers as well.

[@RalphBacon]

I was reading up about the Sparkfun adapter, zodak9999b; the problem for me is that if I change the fuse settings on the ATTiny85 to use P5 then I can't upload further code without a lot of mucking about with "high" voltages to reset that fuse. If this means nothing to you then you'll enjoy a couple of videos that I've just made but not yet released! Thanks for that post, interesting.

[@zodak9999b]

Yeah, I know what you mean. I've avoided using it for anything but reset everywhere I've used that chip so far.

[@artbecker5618]

Thank you for this. I appreciate all your videos. Prices can change every day on AliExpress. Right now the Atmega 168 Nano clone is $1.35, postpaid, while the Atmega 328 version Nano clone is exactly the same price as the full size Arduino Uno clone (no soldering required), which is still under $3, postpaid. I am honestly not sure if I ever used any program that could run on an Uno that couldn't run on a Nano. One (minor?) complaint is that the photo of the Nano clone you are buying isn't always the same as what arrives. The CH340G USB to serial chip has always worked great for me. The other popular converter, the CP2102, doesn't have a driver for Windows 8 (but it does for Windows 7 and I think Widows 10). The best way to determine the identity of any IC/chip is with a small flashlight and a magnifying glass. The tiny (hence the name) ATTiny clones can work for many Arduino sketches (as shown in your video #66), but they cost more than the Nano clones. Thanks again. Your videos are great.

[@RalphBacon]

And I *always* appreciate it, Art, when viewers express their appreciation! Seriously, how else do I know that what I am doing is of any use or interest to anyone? Great to hear from you.

[@javierpallalorden]

Hi Ralph, very nice video, thanks! I like it when someone improves something. The use of the 555 is rather poorly implemented for using it in a PWM setup. I use the same arduino boards (SMD on single side), they are easy to stick on something.

[@RalphBacon]

I agree, Javier (well, I would do wouldn't I!), a case of adapting what you have to what you need. Or, Necessity is the Mother of All Invention (with the standard British meaning here, not the US Slang). The single sided boards (Nanos with ATMega168 chips) are doubtless fine for a huge proportion of projects - and if your project is too big, move to a Nano with an ATMega328P, simples! Thanks for your post, nice to hear from you.

[@DrexProjects]

I have used the ATmega328P-PU 28 Pin DIP soldered into a prototype board with a 16Mhz crystal and a couple of 22pf caps. Sometimes I will add a rest button. I have an uno board that has a 28 pin dip socket on it that I program the 328 with. Then remove it and stick into the prototype board. Cost is somewhere around a dollar Canadian. Recently I have received a dozen or so ATMEGA8A-PU chips and when I get comfortable programming them I will insert them into small projects. I'm rambling now... Thanks for all the great Vids Ralph.

[@javierpallalorden]

Hi Darrell, whenever I use the ATmega328-PU I always use it without the crystal. I run them on the 8Mhz internal clock.

[@pekkagronfors7304]

You could stick the pins in a breadboard and then solder the Nano board onto them. Then you got board/pins in a straight angle.

[@RalphBacon]

Which is what I normally do Pekka, except on this occasion I was rushing things (to continue videoing) and of course it was *A Bad Idea*. Now everybody thinks my soldering skills are rubbish . From now on: no rushing things. But your suggestion is a great one and I bet there are people reading this who didn't know this tip, so thanks for posting!

[@tchristell]

Hi Ralph: Always enjoy your videos (especially your sense of humor). I have Banggood arriving weekly. I was wondering where you got the development board for the Nano. Todd

[@RalphBacon]

Hi Todd, thanks for your support. I've no idea where I bought my Nano expansion board but it was probably at Banggood similar to this one: www.banggood.com/UNO-Expansion-Board-ATmega328P-Nano-V3-Improved-Version-For-Arduino-p-1011008.html?rmmds=search You have got to solder the pins in yourself but that's it. You could even use different coloured pins for the analog pins if you wanted to (see my latest red-board Uno for an example). It's a very good way to develop stuff, same size as a Uno but much more flexible in actual use. Good question, thanks for posting.

[@tchristell]

Thanks for the link Ralph. The expansion board PLUS a Nano V3 for $5.83! How can you beat that? Ordered two plus a bunch of things I probably don't need:) Keep up the good work.

[@RalphBacon]

Any cheaper, Todd, and they would have to pay you to take them away! Regarding the "things you probably don't need", even if you don't actually need them right now, one day you will. For sure!

[@daijoubu4529]

When i tested the current consumption of my pro mini, the 168PA consumes a bit more than the 328P-AU, the latter is also available in that smaller package. There's also a black (as well as a blue one) "shield expand" version of a pro mini with Vcc and GDN for each of the pins.

[@RalphBacon]

Great bit of information there Daijoubu, thanks for sharing. Frankly, I think my "expansion shield" for my Nano to be brilliant so I'm sure the one for Pro Micro that you mention is equally good. I wonder why the Pro Mini consumes more current? Higher clock speed, perhaps? Perhaps someone reading this will let us know?

[@daijoubu4529]

I wonder if maybe because the fuses were set for a full swing crystal, I would rerun some measurement. And here's the board www.ebay.ca/itm/New-Atmega328-Board-5V-14-Pins-Pincompatible-For-Arduino-Pro-Mini-/262693409602, needs a separate CP2102/CH340G or FTDI breakout however Robotdyn.com has a very cheap 328P Nano however, $2.17 USD pins unsoldered robotdyn.com/catalog/boards/nano_v3_ch340g_compatible_with_arduino_nano_v3/, 168 is $1.99 soldered

[@daijoubu4529]

Nop, both are set to 0xFF for the low fuse, datasheet seems to indicate that the 328P uses slightly more current which is inline, so the only difference is during deep sleep That's on a Pro mini without the power led and the LDO at 3.3V 168PA-AU SLEEP_FOREVER 20.6uA IDLE 5.25mA 328P-MU SLEEP_FOREVER 0.1uA IDLE 6.5mA

[@RalphBacon]

Interesting figures there, Daihoubu, just goes to show that "similar" boards are indeed "similar" but can be quite different in some ways that may be important to some people who want to run on batteries, for example. Thanks for letting us all know!

[@roberteliassen5020]

Ralph, the resistance of your pot and the 2k2 is (x*2200)/(x+2200) as we all know. That would be a hyperbolic function (if I remember correct). You can plot that on geogebra.org or whatever plotter you prefer. www.geogebra.org/apps/ Great video, by the way. Thanks!

[@RalphBacon]

Hey, Robert! Great to hear from you again! Not sure about this being a hyperbolic function but I did graph the resultant resistance (bearing in mind that I'm guessing that the other end is to ground, it might not be) and instead of a 10K linear trend to zero, I get 1.8K initially, then 1.76k, 1.72k, 1.67k, 1.61k, 1.52k etc all the way to 0 if measured at 10 equal steps on the potentiometer. Maths notwithstanding, it works very well and is in daily use on my desk (even if the module is just screwed to a bit of old wood attached to the fan - I'll have to clean that up one day!). Thanks for posting Robert :)

[@roberteliassen5020]

I think if f(x) is a fraction and the x is in the denominator, it would be a hyperbolic function. I might be wrong. Anyway, you videos are always appreciated (in my opinion). Still not sure about the static variable instead of a global though, but we've been there and agree to disagree. :)

[@bigrickshaberdashery2759]

uno 's are great but love my nano's and the pro's. stick them in a shield and away we go

[@RalphBacon]

Yes, agreed. I use Nanos for actual implementation but use the Arduinos whilst I demo and develop. Or I use the Nano development board which is even better as I can plug in the Nano but have many pins available.

[@igrewold]

14:21 that's a cool move, putting a colored semi-/transparent sheet on the led matrices :) Is there any tactic/technique to how it is done? red on red, black/dark gray on red...etc. (what works best for each led color...etc.) thanks and regard

[@RalphBacon]

Use the colour of the LED; in my case the LEDs are red so I use a red acrylic sheet. That makes everything look black and the red LEDs even redder. If you have blue LEDs choose a dark blue to get the same effect. Thanks for posting.

[@igrewold]

Thanks a lot, Ralph :)

[@JMParsell]

Hey there Mr B. Sorry to ask a question not relevant to this video, but I don't know where else to ask... I am interested in powering some projects with 3.7v lipo batteries. Keeping this brief, would you please explain how to charge and power arduinos from the same device? May be even make a video on various battery power/charging options. You're the best, thanks!

[@RalphBacon]

Hey JMParsell, (I'll call you Jerry, it's friendlier)! What you really, really want is a nice video that demonstrates a LiPo charger module. Now where are we going to find one of those? Right here of course! You need to watch my video #50 TP4056 UPS - protect from power outs and brown outs (link: kzbin.info?o=U&video_id=7wgzaVQzLgE) - it will at least give you a heads up on what is out there. Have a look and see if it is what you're after!

[@JMParsell]

Thank you. Sorry that I didn't look ahead, I'm watching your videos in order.

[@adabill295]

Hi Ralph, Once again a great video. I am using a ESP8266 in most cases now (Internet capable) and I really miss the fact that there is no PWM available on the chip. Is there some other chip or device I can add to get this feature back. I would like to control a SSR for Sous Vide cooking and the PWM is the easiest way to control it. It would also be very helpful to control the illumination from LED's.

[@RalphBacon]

Well, AdaBill, you could (dare I say this) add a $2 Nano 168 back into the mix which would give you 3 channels of PWM. A cheap solution and guess what? You know how to program an Arduino. You could send the data via the Rx/Tx ports. Or use a TLC5940 16-channel PWM chip, there's even a library for it (see forum.arduino.cc/index.php?topic=37963.0). Either way there's no need to go without your daily dose of PWM. :)

[@adabill295]

Ralph, Your right, I hadn't thought about using an Arduino to get the PWM i need. I haven't done anything with communicating between devices vi RX/TX. I'll also check into the TCL5940 chip. Your right though, I already know how to program the Arduino/ESP8266 VIA The Arduino IDE

[@robertheal5137]

pwm is probably going to change the duty cycke, not the frequency

[@RalphBacon]

Indeed, Robert, that is what it *should* do, but as the 'scope trace shows, the 'space' remains constant whilst the 'mark' is changed (stretched). Frankly it's all a bit bizarre, I've never seen a PWM do this - but it does work at the end of the day. I'll just lodge this one at the back of my brain, marked 'weird PWM' !

[@jwcolby54]

Does the code go in flash or sram? And why is there eprom when the flash exists?

[@RalphBacon]

When you upload the sketch it is stored in non-volatile flash memory. At run time (when you switch on) it runs from there using the SRAM for variables. EEPROM memory is much slower and cannot be used to run programs from. It is there to allow you (the developer) to store data, variables, your wife's birthday in non-volatile memory that you can access it when the program is running. It wears out a lot quicker than FLASH memory (1,000 writes vs 100,000, I believe). So you have to be careful what you write, how often you write it and where you write it, using wear-levelling algorithms, the subject of many university theses.

[@mickm7608]

Hi; Milton Keynes - have you worked in Formula 1?

[@RalphBacon]

Can't say I have MIck, so if you were hoping you'd found your long lost uncle, it's not me, sorry! But thanks for watching my videos nonetheless!

[@aspectcarl]

Milton Keynes!

[@RalphBacon]

Land of the Concrete Cows! Oh, and roundabouts. And a funny V[ertical] and H[orizontal] road naming system. Something tells me you might know of MK, Carl?

[@aspectcarl]

Ralph S Bacon near V4 :) Milton Keynes south

[@RalphBacon]

Nice to have a relatively local man along for the Arduinite ride! It's a small world!

[@SpeccyMan]

The Nano is probably my favourite form factor for the Arduino but I recently made a start on my Robot Buggy build fully intending to use a Nano in the project but decided to opt for a Pro Mini instead. My first time actually using a Pro Mini in a project and I'm happy with the outcome. The Robot is still a project in progress though, mostly experimenting with ideas for now. Photos here if you are interested. imgur.com/a/QKKBp As always an interesting video. Thanks.

[@RalphBacon]

Yes, the Pro Mini is fine (apart from no USB socket so FTDI programmer required) and smaller than a Nano, tis true. I like your workbench. I love your quote "A tidy workbench is an unused workbench." In which case yours is mildly used but mine must be in use 25 hours a day (ie very untidy except at weekends when I blitz it and put things away). You buggy looks very nice, very neat. You have the same PSU as me except mines digital, and even the 'scope looks quite similar. Like me, though, you could do with a workbench 3 times the size and it would still be too small, hey Nick? I mean, where are you going to put the 3D printer, laser cutter/engraver and CNC machine?

[@SpeccyMan]

Sadly, I don't get to spend as much time at my workbench as I would like. Kidney problems mean I get really tired very quickly so I have to do my tinkering in short bursts when I can spare the energy. I do have a little wooden trolley to the left of the bench which serves as storage and also a little fold-away table I can use when I need a bit more space. My flat is small so items like a 3D printer etc. are but a pipe dream.

[@RalphBacon]

Sorry to hear that your health gets in the way of your workbench, Nick. Just relish the moments when you are there :) The 3D printer is pipe dream for me too until I get a man-cave (huge shed) one day, once I've won the lottery, that is. In the meantime I'll just make a few more videos...