Postbag: #26 - 74HC595 PCB, 30V LCD Meter, Qi & USB Charger

[@jeffmerlin2580]

At 00:50 you said: "So, one of the things you can't do on an Arduino, is write an 8-bit byte of data to an 8-bit port. You can't write, in one go, a byte to an output". Well, indeed you can. With PORTA, PORTB, PORTC, PORTD etc. PORTD = 0xff will set pin 0-7 high provided they are set to output. I love you videos by the way, just feel like nitpicking at the moment. :)

Do not fully agree with the statement on 1:06 about writing 8b in parallel. For instance, you could use PORTB=B101000; to set digital pins 7, 5, 3 HIGH and pins 6, 4, 2, 1, 0 LOW in one go. The example is straight from arduino's PortManipulation reference page.

[@JulianIlett]

Álvaro M. Valdebenito B. Good point. What I said in the video wasn't really right at all! I'll annotate that bit, and buy myself an Arduino Mega (clone) - That should have all the parallel ports I need.

[@superdau]

You can do that. But on the mega328-Arduinos two pins of port B are used for the crystal and on port D two pins are used for serial. If the update rate doesn't need to be high (high being >100kHz let's say), a 595 is maybe less trouble.

[@JulianIlett]

I was thinking about getting a Mega2560 - the big Arduino with loads of IO

I also agree that daisy chained 595 are less trouble, and less pins (and cheaper), for practical applications. My point was that it is possible, if I one really wants it.

[@lezbriddon]

Julian Ilett PORTB=B101000 would work on the 2560 too

[@fatpo888]

13:56 the 2 5-pins ic are just like DCP. TI has TPS2511 to fulfill same purpose

[@pcuser80]

The Currah microspeech for the ZX Spectrum uses the spo256 speech chip.

[@KX36]

This may have already been said, but port 2 of the charger does have the 4 resistors for apple data voltage levels, just 2 of them have been moved slightly because of an unpopulated SOT23-5 pad.

[@bigclivedotcom]

I had a Fuller speech unit for my ZX Spectrum that used the SPO256 chip. Then I bought a chip from Tandy and made my own speech synthesiser for my Sinclair QL. I always wondered about the AL2 bit at the end. I guess it means allophone set 2. But what did allophone set 1 sound like? If you want a modern alternative then check out the speakjet chip.

[@JulianIlett]

bigclivedotcom I bought the ZX80, but returned it when I found out about the TV sync loss while running programs. Silly, I should have kept it. Then I bought into a rack and card Z80 system and switched mainly to assembly language programming. There's a little history on the SP0256 on Wikipedia en.wikipedia.org/wiki/General_Instrument_SP0256. One of the links takes you to a Microchip datasheet for the SP0256B - interesting. Just took a look at the SpeakJet - nice, but no better than the SP0256 from a comprehensibility point of view. I guess I've been spoilt by the likes of Google Now and Siri.

[@bigclivedotcom]

Julian Ilett The way the ZX80 just abandoned the screen whenever a key was pressed was terrible. Almost as bad as the ZX81 allocating video memory to program space making the displayed image smaller as you typed in extra program lines. The Speakjet chip may actually be based on a PIC microcontroller, which is an impressive feat. But in my opinion it would sell better if it was somewhat more affordable! One of my favourite things to do with the AY SP0256 chip was to write a simple loop that sent it a byte of random data followed by a delay so that it just churned out robot gibberish.

[@JulianIlett]

bigclivedotcom I never knew that about the ZX81 - If you kept typing, did the video size eventually become zero? Clever way to increase the program memory though - a lifesaver if you need 'just one more byte of memory'. The image of the SpeakJet on Spark Fun does look like the original chip markings have been rubbed off. When I get the SP0256 working, I'll probably write an incrementing byte to it first.

[@bigclivedotcom]

The ZX81 screen would progressively go black in sections from the bottom up to a point where there were just a few lines at the top left. You had to optimise your program to the nearest byte that didn't steal screen space.

[@simonjcastle1]

bigclivedotcom I dont recall that issue with the screen on the ZX81, I only had 1K for a short while before I got the 16K backpack so may be it wasn't an issue. It also had the loss of screen image if you put it into fast mode where the CPU would not do the video stuff. I do recall poking all my assembler by hand into 16514 which was the location of the first byte of the first rem statement. That address and 201 for the z80 return instruction are engraved in my brain for good. I binned most of that stuff but I still have my Specky and IF1 with Microdrive.

[@HillOrStream]

I believe that is the chip I had from Radio Shack. I built it into my Atari 400, driven by the joystick ports. Used it for years with a cassette tape recorder and a modified modem to take phone messages or switch to the modem for the BBS I ran. A caller would be told to hold for 30 seconds, then a carrier was sent while the 400 monitored CD, if that timed out it would ask the caller to leave a message and roll the cassette. Over three decades ago but may still be my most complex project/program.

[@Leonelf0]

Yes you can set bytes to ports on arduino! They use Atmegas, so you can use direct port manipulation!

[@healthman777]

Your Videos are always great thanks!! Maybe put the new LCD in a ZIP lock and seal it up except the corner ... they have worked very well for me in the past as a temporary solution. :)

[@iceberg789]

hi, about that usb car charger: smaprt ports are supposed to adjust the voltages in usb data lines to find out maximum current draw for the connected o/p device. cause some high end fones put these tricks in their usb charging systems.

[@DantalionNl]

seems like all 3 universal usbs from the ec technology charger have the same resistor network the one on the second port is only slightly different alignment, but the resistor codes are the same.

[@douro20]

We put a couple of similar LCD voltmeters in one of our trailers.

[@thejo6331]

Shortly after Apple released the iPad, USB specs were revised to add the ability to up charge current from 1A to 2A. Only problem is that they couldn't enable it for every device, or else they could seriously mame older devices. So these "smart" chargers actually use some of the data lines on the usb cable to talk to the device and essentially ask it if it can handle the 2A charge. It it responds yes, the charge device goes into quick charge mode. If it responds no (or more often, sends back no response at all) the charge current remains limited at 1A.

[@Edu_RJR]

those smart ports chips could only be dedicated charging controllers, similar to the TPS2511 but they seem simpler.

[@erlendse]

For the bike battery, do get a BMS like the one you mentioned. I would suggest you get a fixed function charger too, even the BMS will allow you to get away with accidentally using the NiCD charge program on lithium batterys. The RC chargers are neat, but not exactly something I would build into/use as part of other things. Fixed charger and BMS and you should be rather safe. Do NOT skip the BMS. There are details for the packing too, but I rather not advice on how to stop a flaming battery. Don't go super-cheap on those parts. As for IO pins, a AVR microcontroller and a breakout board should give you lot of paralell IO. One of those 64/100 pin TQFP SMD packages would give you LOTS of 8 bit ports. (and ports in general) As for me, xmega and avr dragon looks tempting. I have looked at the xmega datasheet, and it lists features like DMA and internal routing network.

[@velocityphotography6758]

Port 2 on the USB charger has the same resistor matrix, but the other two are below and to the right, aren't they?

[@superdau]

Yes, definitely the same values, just different layout.

[@JulianIlett]

Ak OK, well spotted. I didn't notice that.

[@twirlywhirly555]

Id just use a RC charger / balancer for them LiFe cells , I did with my 12 cell 12Ah pack and never had issues .

[@TheOldmankk]

I like Dave Mailbag Monday, I like Julian Postbag Saturday. The two days worth living...hahah....

[@Techn0man1ac]

Hello. Where are you from and what kind of search engine do you use?

[@MartynDavies]

My SP0256 has long since vanished. I've still got its companion CTS256 (text to phoneme) chip though.

[@JulianIlett]

Martyn Davies Everyone's looking for one of those! Should be worth a few quid.

[@blablablaqwd]

I wonder if the car charger can supply 7.2 amps as printed on the cover :-) Could you load test it? Thank you for the reviews!

[@68MalKontent]

Why not use a PCF8574? It's self-contained I2C to parallel, and hardware I2C can be used to drive it in no time.

[@EnricoConca]

I don't quite like those 16V capacitors on the 36W USB charger: a car with engine running might provide over 14V on the cigarette plug, and I'm concerned about the life span of the product. As for the IC on the smart ports, I think I read something about a very similar chip from TI: basically it should be a current-monitoring IC, which can rearrange the voltage on the D+/D- lines until the connected device draws the highest possible current.

[@miniwarrior7]

that BSM is only designed to keep from over charging and over discharging, it isn't designed to be a cc-cv battery charger

[@Designandrew]

I wish you would get into fpv flying wings/quadcopters because I think you would make some awesome things

[@JulianIlett]

Designandrew My brother just bought a DJI Phantom 2 - playing with that was a lot of fun. Now I want to continue with my ArduCopter project. I'm re-inspired.

[@Designandrew]

Julian Ilett Thats good to hear Julian. I'm not a fan of Phantoms, they seem to be purchased by novice who are more interested in photography than the RC hobby, and they don't take proper precautions or bother to learn the dangers associated with the hobby. Then they blame other when they crash. If someone is wanting a phantom the best thing they can do is buy a mico quad first, a hubsan x 4 for example. They are cheap yet give you the full controls and teach you the basics.

[@MrAbhilashgopinath]

plz think to make Studio Strobe light with using high power LED controld by ardunio trigger. is it possible (high speed sync) now most of them have DSLR camera online strobe flash lights are highly expencive

[@ChrisBurtonUK]

Probably a Genesys GL888F in the car charger.

[@JulianIlett]

Chris Burton Ah, well spotted. Neat chip.

[@Mixbag]

The chip can be found using the following on google GL888F 888F2 USB fast charging

[@TheSuraj03]

Julian Ilett I was going through some Chinese electronics stores, the high voltage led meter that they have is usually 3 wire. Do you have any thoughts on the 3 wire solution Vs the 2 wire solution they have on the low voltage lcd ones ? ..

[@JulianIlett]

TheSuraj03 The 3-wire meters require a separate power supply - which can be a nuisance.

[@TheSuraj03]

I see, thanks!!

[@alien8r33d]

The post concerning the SP0256 below is by me and NOT Susan Irving. She has signed in on my computer again, without permission and she has been dealt with accordingly.

[@Vhbaske]

A project kept in the shelve for 25 years! It looks he is describing me also....

[@TommyAventador]

Julian can you buy a MSP430 Launch Pad and do a review and give some info what it is. Is it like a Arduino mega2560 or Uno? If you can that would be great. Cheers 🍺🍺

your videos are great ...but what about order a camera tripod !!!

[@chartle1]

Why stop the bike? Why not mount the meter on the handle bars?

[@JulianIlett]

Cliff Hartle I'd still have to reduce the throttle to zero to check the off-load voltage

[@cottsak]

Just curious, why the LiFePo4 for the bike instead of NCR18650Bs or similar LiIons? Is it the current you need or something?

[@JulianIlett]

2 reasons. Connecting them up is simpler. The LiFePo4 cells have screw terminals so no soldering needed. Also the chemistry is safer, they're much less likely to go up in flames. That's important when the battery pack is directly beneath the saddle.

[@cottsak]

So safety and soldering convenience is more important than cost and capacity?

[@JulianIlett]

Safety certainly. You may have noticed that I never buy cheap electronic stuff that connects to the mains. Soldering to 18650 cells is difficult and if not done properly, also becomes a safety issue. Cost is always a factor, but it will never be more important than safety.

[@FireSwordl]

I wonder can I find a voltmeter which measuures lower than 2.5V, without external power supply, for my supercapacitor banks....

[@JulianIlett]

***** I've not seen one.

[@gamerpaddy]

Good Morning all! instead of Moooorning all! Oh, this must be a hidden special :D

[@JulianIlett]

Just trying to keep it fresh! I'm trying to think of a closing phrase to use at the end of each video. Any ideas?

[@aerotro]

Julian Ilett > Good Evening All < !!! Maybe a sarcastic remark that you spent all day making the video < jokingly

[@stmounts]

Julian Ilett Thank you, goodnight and may your god go with you.

[@electrodacus]

Julian do not get that BMS. I have one of those I can send you for free just pay for shipping. But I can not recommend even that. Is probably OK for over-discharge but not good for overcharge. They use an IC with fixed threshold and that is set at 3.9V since is for LiCoO2 not LiFePO4. I can send you one of my Solar BMS if you want to make a review video about. You can see what is about on my channel.

[@JulianIlett]

***** I've seen your Solar BMS, very nice looking unit. So I trust your advice on that BMS completely. Eclipse Bikes have their own BMS which does have the overcharge voltage at 3.60V www.eclipsebikes.com/lifepo4-288v-cell-30a60a-p-1040.html It's a bit more expensive (£30), but from what you're saying, well worth the extra cost. I would love to try your Solar BMS - can I contact you when we have a little more sunshine?

[@electrodacus]

Julian Ilett That one from eclipse bikes is exactly the same look at the overcharge detection voltage 3.9V. They all use the same 5 or 6 pin IC one for each cell and they detect over-voltage as 3.9 or 3.95V. This chips are old and extremely inexpensive that is why they use them but not good for LiFePO4. I will not have designed my solar BMS probably if they had a good BMS for LiFePO4. I will contact you for the address and send you one of my Solar BMS and also include one of those BMS PCB's so you can test and see how they work. There is no hurry to make a review about the SBMS. Martin works on a video right now so you will see his impression. I will probably do another campaign beginning of next year with a new version of the SBMS with a lot of improvements.

[@JulianIlett]

***** Oh yes you're right, I was looking at the wrong parameter. Looks like I should stay away from off-the-shelf BMS units completely. I'm going to watch all your Solar BMS videos later, but can I ask one question? Can it be used with a PSU at the input as well as a solar panel? Regarding the SBMS, please contact me at: [e-mail]

[@electrodacus]

Julian Ilett I already wrote you an email but yes you can use a constant current power supply like the one you use in most of your videos. Just set a voltage that is higher than battery voltage voltage when fully charged and set the current to whatever the power supply supports comfortably no more than 0.3C of the battery just not to stress the battery to much. For LiFePO4 even 1C is good if you are in a hurry but is a bit much if is not a A123 system those can be charged even at 2 or 3C with no problem do to extremely low internal resistance.

[@aerotro]

Nice Review Julian but personally I avoid all wifi stuff too much Microwave Pollution as it is lol

[@JulianIlett]

***** Actually, the wireless charging takes place at quite a low frequency (110-205kHz it says in the manual). But you may not like my upcoming review of the ESP8266.

[@Gigawipf]

Julian Ilett Looking forward to your ESP8266 Review. Just got one of them some days ago and it works great but i need some ideas what to do with it ;) It has some pretty good range. Probably more tx Power than allowed

[@aerotro]

Julian Ilett Hmmm let me Guess it's in the Microwave band ;) the only reason I have become somewhat perturbed by microwave devices is a friend of mine suffers great health issues from any wifi technology. So much so he was forced to move to more remote locations, he has done extensive research on the subject perhaps you might like to check out some of his research sometime ? seahorsecorral.org/emrdvd.html Keep up the Great work Julian

[@haydenc2742]

I designed a few OSHPark boards using TPS2513, which is an autoranging DCP enumerator chip, the smart ports probably work something similar Datasheet: www.ti.com/lit/ds/symlink/tps2513.pdf My design: oshpark.com/shared_projects/sTExw1i9

[@FunkySpunkyJunky]

for a second there, i thought you were going to charge up a can of coke.

[@JulianIlett]

Funny you should say that. I made a silly comment about that while filming, but cut it out during editing.

[@ceech123]

I meant to write you before, and since I saw you struggling with the round LiFePo4 battery enclosure, here is a suggestion for rectangular version: www.ev-power.eu/LiFePO4-small-cells/?cur=1

[@JulianIlett]

ceech123 That's interesting - certainly a more convenient shape. Have you bought from them?

[@ceech123]

Yes, I did. I tried 10Ah and 15Ah ones. They perform well in a solar-panel-mounted charger/power source. I used an additional battery protection IC that has a cut-off voltage set at 10.5V. And the BMS protection circuit (www.ev-power.eu/SBM-CBM-1-1/Simple-Battery-Management-Board-4-cells-12V-10A.html?cur=1). I'd like to see your take on battery protection circuit, since they all seem to have different discharge detection voltages.

[@enginbilgi]

8:55

[@MattBaker1965]

I still have my Everyday Electronics kit speach board for my ZX Spectrum. I was going to attach it to an arduino but it looks like you have beaten me to it. Anyine want the SPO256 ? I want Top Dollar ;-)

[@ShaunDobbie]

You should stay away from BMS (battery massacre systems) because they do precisely that. I got a brand new electric bike and had to replace all the cells in it because they were puffed up due to overcharge. It is better to use an external balance charger as you can monitor the voltage of all cells.

[@kingredleg6747]

I found RFToy on youtube and thought of you and you RF transmitter project. Here is a link to the video. kzbin.info/www/bejne/g6GZdIuhbLaneas I look forward to seeing your video's.

[@JulianIlett]

King Red Leg Strange name, but it looks like a well thought out device