Julian's Postbag:

[@illchmann]

This oscillator is a Wien Bridge oscillator. The bulb is for gain control to not go into clipping.

[@rich1051414]

Like this? tinyurl.com/yyrp5lm4 So the bulb is just the 100 ohm resistor I used in mine?

[@drkastenbrot]

If you peel the sticker off that caliper, itll reveal some funny looking metal tracks and pads. The act as a variable capacitor with the plates on the bottomside of the moving part. They cant skip steps because the sensing system is absolute.

[@douro20]

The Tesa Shop-Cal has those capacitive plates exposed.

[@mbaksa]

Listing with caliper and USB charger makes no sense. But lately sellers started packing two more or less unrelated items - one cheap, and one expensive (that you actually want to buy). The reason is that more expensive item then appears much higher in the search result when buyer chooses ordering by price. So this about $4 (or whatever the price was) caliper would be listed at the top, as $1 item. This shady practice should be forbidden by eBay.

[@zerog2000]

yeah it's listing fraud.. the option thing is only supposed to be for variations of the basic same thing, e.g. differnt color, style, or for example US vs EU plug... Chinese sellers have been abusing the crap out of it for listing "click bait"

[@roidroid]

Listing fraud has gotten so bad that i automatically skip ANY multiple listing now. I wish there was a way to eliminate all multiple listings from my searches entirely.

[@DrexProjects]

Same here.

[@pirateman1966]

So you bought a caliper and used your ruler for measuring? Nice.

[@anullhandle]

He needed the enhanced accuracy LOL.

[@SianaGearz]

The reason the lightbulb goes instantly dim is because it starts off with a very low resistance many times lower than its nominal one! As it heats up to temperature, the resistance shoots up within seconds. Plus you can imagine your battery as having a parallel capacitance due to its layered construction, so after you draw a good bout of current out of it, its ESR too goes up.

[@nThanksForAllTheFish]

HP's first product (HP 200A) was an audio oscillator that used a bulb as non-linear feedback element to keep output amplitude constant over 3 decade frequency range.

[@proluxelectronics7419]

You got the new super accurate calipers then the old faithful ruler came out.....

[@JulianIlett]

+Mike James ha ha, the irony :)

[@ElmerFuddGun]

0.1mm resolution is far from "super accurate"! You should be able to find stainless steel calipers with 0.01mm resolution and a nice box locally for less than $10-15 (at least while on sale). Your local car and home store (ie. Canadian Tire) should have them so it is quicker than ordering from China and with a local return policy if there is a problem. Plastic will wear especially if you are turning round items a lot to find the narrowest or thickest diameter.

[@tengelgeer]

Canadian Tire in the UK? And in the Netherlands you can't buy a digital caliper for $15,-... Make that €30,-... Which is a big step up from China. Branded calipers are better (especially on battery life) and indeed, plastic just sucks, but for the money you can complain.

[@km5405]

*super accurate* ... well better then the old faithfull ruler though .... a man only has so much patience for reading things accurately.

[@PhilXavierSierraJones]

The caliper package is for all the ranges of products made by that factory -- they are supposed to put some sort of marker on the one that the product inside is supposed to use. p.s. Those calipers only turn off display and do not have an actual sleep mode. You might want to put some sort of physical switch in place of on/off button.

[@KX36]

1:58 Because it's always on, only the screen turns off. They drain batteries even when "off".

[@massimookissed1023]

14:10 You have a caliper that measures inches...

[@Whatsthegeek]

the lightbulb is use to stabilize the oscillator. It's actualy a pretty common technique.

[@ultort]

For the caliper, it's not a roller, it uses a Hall effect sensor with an alternating North/South pole magnetic strip

[@tiger12506]

Just so you know Julian, don't damage that sticker rule, it forms part of the capacitive sensing for the digital calipers. I don't know exactly how it works... but if you take it apart, there are bare pcb traces facing that sticker and that's how it measures. (I damaged one and it doesn't work consistently anymore)

[@JulianIlett]

Well now I'm even more tempted to peel it off :)

[@raymondheath7668]

A couple years ago I picked up some new old stock HeathKit Digital traning boards which evidently mount into a larger box with backplane connectors. All of the boards had mapped out sections for digital logic and all of them were surface mount components. I had hopes of finding schematics and a manual, but alas, the information seems to be very rare

[@tazz1669]

The calipers are quadri calipers and have 4 measuring faces, you found 3. The fourth are opposite the hole depth gauge end if you turn them over when you slide them you'll notice that the end face and the back of the caliper have 2 parallel faces which can be used to measure stepped faces. Don't worry most engineers don't know that either. I've only used the metal versions as I'm not sure how accurate the plastic ones would be. There is also a reason they are called verniers, as the readings are only very near, real inspectors / engineers would use something a bit more accurate tolerance dependant but when your working to .0005" or .01mm accuracy they are not so good. Still ok for measuring most stuff.

[@ThirdPer3on]

Yeah I got some of those converter pcb's awhile back, SUPER useful when you use components from old electronics. Things like the small power on reset IC's and logic. Lots of logic IC's now can be quickly reused. :P

[@douro20]

I would suggest getting an SR44 silver oxide cell to put in those calipers if you are going to use them a lot. Some shops sell them quite cheap.

[@roidroid]

You need to measure it while the battery & caliper are both perfectly horizontal, it might show 18.0mm then. Hard to do when holding it in your hand, you're introducing a slight vertical angle.

[@peterthinks]

The little stick that comes out of the end of the calipers will measure hole depth too.

[@MicroSD16Gb]

There is no rubber roller there. Under the ruller sticker there are metal contacts and the caliper is measuring the capasitance change during it's moving.

[@mbaker335]

INA3221 library. I see you have found the information that you wanted but even so writing your own library I would have thought would have been interesting. I would imagine it involves going through the chip datasheet and writing a set of routines that will communicate with it to achieve the functionality that you want. Certainly worth doing once to gain confidence for future projects.

[@danweecc]

The string of diodes in the sine-wave generator is nothing more than a signal clipper - basically back to back zeners of 2.4V (4 x 0.6V) that clips the output if it exceeds that voltage. The circuit will probably work fine without those diodes.

[@mrjohhhnnnyyy5797]

Yes, but there are 5 in a string ;)

[@danweecc]

oops - I missed some of those angry pixies - 3.0V then.

[@mrjohhhnnnyyy5797]

It's alright, fellow AvE fan :D

[@petehiggins33]

It's a bit cleverer than that, the oscillator is a triangle wave generator and the logarithmic diode forward voltage curve converts it into a rough sine wave. Obviously still not as pure a sine wave as a proper sine wave oscillator like the Wien Bridge circuit used in the kit.

[@mrjohhhnnnyyy5797]

number 33 Good point

[@DoRC]

It's a hall effect sensor and a special strip under the ruler sticker

[@eekpie]

Calipers silver number sticker is a capacitive grid. It will always return to setpoint or 0.0

[@mikehudson3620]

Plastic calipers are so much better for measuring the length of the battery!

[@rwbishop]

More on the calipers... If you'd like some decent calipers, look into a pair made by either Mitutoyo or Starrett.

[@km5405]

but those cost a non trivial amount of money :(

[@rwbishop]

You get what you pay for... plus, econobudget tools are no bargain. Get good tools, care for them and they'll take care of you.

[@rwbishop]

More... and note that good tools can be found for much less than retail... in particular check Craigs list and similar sites; especially near the end of the month when people need fast cash.

[@Raphioso]

If you take the analog ones, you can get mitutoyo ones for

[@srjskam]

To be pedantic: that's not actually a Vernier caliper. 'Vernier' refers to Vernier scale that you can use to read out fractions of the main scale graduations on a mechanical caliper.

[@arifanwari3168]

Julian don't forget you can use your new digital callipers to measure the pin spacings. :)

[@tablatronix]

That assorted battery pack is ingenious

[@reeseyme9613]

anyone else is still waiting for julian's to work on the ESP module he got it in the previous postbag?

[@EastyUK]

Some problems with the cheap calipers is they use a lot of power in standby and don't have a low voltage cutoff, so as the battery gets low the measurements get dodgy. for a dollar though you cannot complain.

[@rwbishop]

Far as the calipers go... check the Wikipedia 'Linear Encoder' entry. They produce them dirt cheap these days. Also, I could be mistaken, but I think most, if not all Carbon Fiber is conductive. An interesting experiment might be a continuity test across one of the jaws. Great videos, Thanks!

[@superdau]

The "feature" of the display of the calipers turning on on movement is actually pretty annoying. It shows you that the "off" switch only blanks the display, but the rest is still running. That's why it's very likely that you will come back to a flat battery after a few month even without ever using it. Either remove the battery after every use (which is quite a hassle) or rig something up to disconnect the battery. I use a strip of sturdy plastic sheet cut from the blister pack. I jammed it in under the battery with a tab sticking out that I can turn to break the contact. Also you should get the metal version of these calipers. I got mine at Hofer, the Austrian Aldi (yep, we are one of the only two countries in the world where Aldi isn't called "Aldi") for 12€. They have it randomly once a year. Should be the same with Lidl. My metal version has the exact same display, but displays another digit after the decimal point (where yours is blank). It also has a small metal wheel which is useful for fine adjustments, a locking screw and it's made out of metal so you can transfer a locked measurement easily by scratching (don't tell machinists ;) ) And the thing about the listing: I report such listings to ebay as "search and browse manipulation". Sellers are using the multiple item option to add completely unrelated items with a lower price so it shows up further up in search results by price, while at the same time placing the more expensive item as first item in the title.

[@DrexProjects]

When will you get around to the PIC tutorial again? I have received the board like you have and am patiently waiting for it. Thanks for the Mail bag video. I get 12 to 15 bags a day myself. Thanks to you, R Bacon, Clive and Ave and a few others for the obsession to have the latest and greatest.

[@JulianIlett]

I must be disciplined and get back to the PIC tutorials. I'm a bit distracted at the moment as I'm teaching my daughter to drive :)

[@DrexProjects]

My father taught me to drive. He would get in the truck with a case of beer and say" To the pub Master Edwards" Ya, he was Welsh. It seems I know where all the pubs are now. Anyway. Good luck with that. Only got 3 in the mail today. Canada Post is so slow. They have to hand sort the small packages from china because they can't go in the mail sorter machines. Poor buggers.

[@duncanyoung8688]

Hi Julian it seems that on the power bank that works there are two resistors on the data lines pulled to vcc and ground,the pondland power banks don't have these,I think its something to do with them,I've read that apple devices need them for charging,and it seems my v-usb circuit bennafits from them some how.

[@decee1157]

2,49 for the SOP16??! I paid 0,66 dollars for 10 pieces on AliExpress! Still waiting on them but received some for 8 pin for my ATtiny85 which also was extremely cheap for 50!

[@jedoTAck]

awesome this pencil cursor fits so much this channel of pencil pointing :D

[@JulianIlett]

Yeah, well spotted :)

[@alexgray552]

A sine wave oscillator circuit with a filament lamp in it isn't really 'unusual' - basic Wien bridge oscillator circuits almost always included a lamp for stabilization and days gone by!

[@MonaichFother]

2:00 Digital or vernier calipers arn't meant to be treated or used that way, they are precision instruments to be used with care and delicately to give an accurate measurement. Not a good test.

[@RWBHere]

These cannot possibly be a precision device.The plastic (not carbon fibre, at this price) is very temperature-dependant, and it will wear out rapidly. They're a rough guide only, precision tools are made from metal, and can measure to at least ten times (usually 100 times) the resolution of this toy/scam, and they're off-the-shelf items. _Those_ are the ones to handle with respect.

[@KX36]

INA3221 module has all 3 grounds common to each other. don't know if that screws with your plans for the battery pack.

[@petehiggins33]

I will be very surprised if that "Royer" converter circuit produces a sine wave. Expect it to be square Daddio.

[@KeithCassidy]

Looks like SwitchDoc Labs developed a INA3221 Arduino library: github.com/switchdoclabs/SDL_Arduino_INA3221

[@JulianIlett]

Yeah, I figured something would show up in a wider internet search - thanks Keith

[@massimookissed1023]

Julian Ilett , with the Grounds commoned on those 3 current-sense resistors, isn't the 3221 useless for a 3S battery pack ?

[@ajscomp372]

It would be if the batteries were connected in series, but I think his cell holder doesn't have them connected. So they would be common ground, independent positive voltages.

[@zerog2000]

but i thought from the original video he was musing about charge/discharge balancing? (maybe confusing about bike battery projects).. But yeah, gotta be careful with the common ground ;) One would think, if they made a high-side, multi-channel, wide-input range current measuring ic Julian might be in business.

[@ajscomp372]

They do. Most of the major semiconductor manufacturers make charge/discharge balancing ICs (even high side, multichannel ones with a wide input range). Julian is overcomplicating things by trying to roll his own instead of using an off-the-shelf solution. If he wants to do it just for the pride of having made it himself, though, I can't fault him.

[@flickpad]

That's disappointing. I thought you might describe how the caliper gauge works. It's actually some kind of capacitive sensor. (Peel off the scale to see the surface being measured.) I'd love to know the details of how this operates.

[@proyectosledar]

hi, right now I am playing with ina226 xD Cheers

[@SuperLoops]

so if it hasnt got a little wheel in and it isnt just reading the scale on the sticker how does the calaper work then hmmmm very mysterious also I hope you do the sine wave kit soon and explain what the light bulbs doing

[@timballam3675]

Have the digital calipers, just a warning don't let them get hot in the sun or the they might warp a bit.....

[@JulianIlett]

What is this "sun" thing you talk about ;)

[@nicksanto882]

Hi Julian, I think I am having trouble with the smd resistor on the purple INA219. I've tried to substitute the R100 with an R010 to measure 32 Amps at 12 volts and burned up a board. Could you comment on the correct resistor for the higher amperage modification, please? You called the R100s 100milliOhms and I'm not sure of how that is derived. Thank You, Nick

[@melkiorwiseman5234]

It is highly unlikely that any Printed Circuit Board would have tracks which are capable of carrying 32 Amps, so there's your problem. You need conductors which are able to carry that much current without overheating.

[@pdrg]

Could we have an oscilloscoped shootout of the three sine wave generators for purity?

[@JulianIlett]

I like it :)

[@km5405]

I have one of those calipers too ... actually surprisingly good, but still-. its made of plastic, even if it has carbon fibres in it ....

[@jameshunt2141]

i had some calipers like those, ran the battery out in a week, threw them out and got some second hand mitutoyo

[@massimookissed1023]

James Hunt , same brand as mine :)

[@Roy_Tellason]

I have some cheap ones I got from horrible freight. I just take the battery out when I'm not using it, lasts a lot longer that way... :-)

[@muh1h1]

Never seen a caliper with just .1mm resolution. Every single one i have come across has been .01mm. Still for the money it seems quite usable. I wonder wheather you bought it after i suggested one some time ago :)

[@massimookissed1023]

muh1h1 , 0.1mm resolution, 0.2mm accuracy.

[@JulianIlett]

+muh1h1 I did buy it after reading a comment, probably your's :)

[@muh1h1]

Hope you enjoy them :) However i would have payed a few dollars more to get a metal version with .01mm resolution ^^

[@Brian_Of_Melbourne]

Having thought recently that the plastic calipers I had weren't enough I spent about ten quid on these www.aliexpress.com/snapshot/0.html?spm=a2g0s.9042647.6.2.3WVqjo&orderId=503275973563356&productId=32813753127 So far so good, resolution of 0.01 mm, and stainless steel rather than carbon fibre or plastic. I went for the case to improve the chance of it arriving still straight, almost unnecessary as the vendor packed it very well. Nice to use, especially the the little thumb wheel for fine adjustment.

[@akhurash]

Good buys. I'll get one of those caliper. I need one.

[@akhurash]

Out of stock. :(

[@superdau]

Don't get a plastic one.

[@JMMC1005]

Agreed. Even if the electronics etc are fine, I don't think those plastic jaws will retain much precision with use. Get a good set of calipers made of well-machined steel.

[@ufohunter3688]

Buy the ones made of stainless steel. Like goo.gl/KPvvxF The plastic ones don't last a week.

[@MasterFX2000]

I would order a metal one and with 2 digits in mm mode. 1 Digit is bad.

[@duncanyoung8688]

Hi Julian, I've got a question to ask,its not about postbag but about power supply's! Hear goes,I've a development board based on v-usb its called pixel loader,it basically runs strings of ws2812b led strips,now I use 5v dc usb power supply's,sometimes i use phone chargers, as my development board pixel loader is just a USB stick dongle kind of design with a 328p on board, it just plugs in and runs sketch loaded,Now hear is my problem,some of the USB power supply's don't seem to work,there is power to my board but won't run,its in spec at 5v and I never over load current I only run a few LEDs in a strip. I've a load of them and some work and some won't,do you think is because they may be too noisy? I can't think why they wouldn't work,even when I've no LEDs powered the the board won't power and run,Ime using usbasbloader as the bootloader so I can plug the stick into the PC and change my sketch quickly, I think its something to do with the power supply sending noise down the USB lines maybe,what do you think? Its so strange,I've seen this a lot even with power banks not powering some projects but will others even when in spec.thanks

[@JulianIlett]

If you don't have an oscilloscope and you suspect noise is the problem, try putting a whopping great capacitor across Vcc and Gnd (near the processor of your controller board). That should help diagnose the problem.

[@duncanyoung8688]

Julian Ilett Hi I tryed that,ime thinking now it may be the bootloader,its supposed to exit after 15 seconds of power.ile dig around some more,thanks pal.

[@Ogma3bandcamp]

That caliper will eat your batteries. Take out the battery after every use.

[@charlesdorval394]

Indeed, totally bit me in the ass. I have a very similar one, have a look if there's a little trap door in the back, it's a serial port, let me know if the info isn't in your manual, I'll scan mine it has the data format and pinout and all

[@uvman6648]

InnaSoulSounds Same here...switching the calipers to off just turns off the LCD display...the unit still draws power even when it is switched off. I suspect that all Chinese calipers do this...they must be in the LR44 button cell business.

[@vgamesx1]

Odd, I have the same caliper and it still has the same battery that came with it, from about a year ago... (I don't use it too often)

[@KipKiperMusic]

I've ended up resorting to putting a small switch on mine disconnecting the battery

[@superdau]

I use a strip of sturdy plastic sheet cut from the blister pack. I jammed it in under the battery with a tab sticking out that I can turn to break the contact without having to open the battery compartment.

[@rich1051414]

How the hell does that sine wave generator work, the one using 10 diodes? Does it just chop up a triangle wave? I have always used a LC tank oscillator, hooked up to an op-amp to amplify and drive the LC tank oscillator, and then buffer that for a current backed usable sine wave signal. Like this: tinyurl.com/yyrp5lm4

[@Roy_Tellason]

That's an interesting page, there. The vocoder-related circuit does NOT generate any kind of a sine wave the dual op amps are set up as a schmitt trigger and an integrator, so you would normally get a square wave and a triangle wave out of it. The diodes just modify the triangle wave a bit, but it's not a true sinewave, not at all.

[@rich1051414]

@@Roy_Tellason Yeah as I thought then.

[@VolthausLabElectronics]

I (being an absolute n00b to 3-D printing) bought a digi caliper recently myself to use in assembling my Prusa i3 MK2S 3-D printer and I am getting much use from it now as I design in Fusion 360. Here in the U.S. we have bargain tool stores called Harbor Freight and I picked one of those up for about $15USD. They run advertisements in everything that is printed it seems and every ad has a 20% off coupon. Mine is mostly metal though. Can this be your first digital caliper Julian?

[@JulianIlett]

I think I've got an old mechanical micrometer somewhere, but this is my first vernier caliper.

[@massimookissed1023]

Julian Ilett , I have 2 Aldi digital calipers, ~ _somewhere_ ... and a batteryless analogue vernier caliper which is probably my most used tool. (Not needing batteries, it *always* works :)

[@isoguy.]

Thank you for anothet fantastic vid, love the postbag ones too. Greedy of me i know but are you able to do some longer vids, full project builds etc?

[@JulianIlett]

I fancy doing a project build live stream :)

[@bernt6500]

What is the SN74HC138N 74HC138 DIP IC for?

[@JerryEricsson]

Many moons ago, I decided to tear apart my Daisy Spit'n Image lever action BB gun, that fire control group reminds me very much of what I found inside my old BB gun. Never could get the damned thing back together again. Perhaps that is why I took that stupid gunsmithing course years ago and hung out my shingle, after all every town of 1800 folks should have 3 working gunsmiths! Well in North Dakota it should, and even better if the 3 are close friends who share the work load and tools.

[@maicod]

omg the caliper is sold out. That is your fault Julian :D

[@darkdragonsqd]

what can i search on ebay to find a beginner build kit ?

[@ajscomp372]

Looks like the makers of the INA3221 board are copying the OSH Park style.

[@chazM6116]

carbon fibre composite which might be plastic with CF mixed in?

[@JulianIlett]

I think that's it :)

[@WhiteDieselShed]

A Chinese seller sent me some of those instead of the metal ones, Took me ages to get a refund. They are useful if you only need mm accuracy or measuring magnets.

[@MicroSD16Gb]

oh god, wrote my comment before watched the moment when you see that linear CAP thing

[@andymouse]

off topic again ! on e-bay can I look at a specific seller i.e. Alice, a favourite of yours thought I would ask maybe quicker than looking myself Taa

[@bertoid]

I tried simulating that ETI test generator in LTSPICE (using LT1057 for IC1). Wouldn't oscillate... Anyone got any ideas why not?

[@bertoid]

And by sheer coincidence, after posting the above, I stumbled onto one of the most excellent circuit descriptions given by w2aew, which described an almost identical triangle wave generator (#186). His description didn't help fix the problem, but got me poking about a little, whereupon I discovered that an op-amp input was loading down the vref divider (which it shouldn't). Turns out a mirrored and 2xrotated opamp in LTSpice (to swap the inputs) causes problems. Using an unmodified opamp, it works...

[@bertoid]

Arrrgh, Idiot! Mirror/Rotate was reversing the supply pins to the opamp. Didn't notice that... Sorry to bother you...

[@JulianIlett]

No, that was interesting :) I can't be bothered with circuit simulation - I prefer to breadboard it to see if it works.

[@johncook5872]

Julien, it's sort of 2 transistor Wein Bridge Oscillator. Lamp stabilisation was a common way to kepp the gain aroun the loop at 3 www.circuitstoday.com/wien-bridge-oscillator Cheers

[@JulianIlett]

Oh cool, thanks for that :)

[@johncook5872]

Julien, Hewlett-Packard's first product was the Precision Wein Bridge Oscillator (HP200A) ! Cheers

[@sagnikpradhan3594]

One doubt can we use CTS Signal instead of DTR Signal for reseting Arduino ?

[@zerog2000]

CTS is input signal. RTS can be used as alternative to DTR for reset. I think avrdude does this by default on recent builds. (I think arduino ide has this.)

[@sagnikpradhan3594]

Jens Jensen Thank You......

[@leotub7]

What is the rug on the table ?

[@trinidad17]

It's a cutting mat

[@leotub7]

T Trindad Thank you ;)

[@thepvporg]

Should look at the one I just bought from a UK seller. What a joke, cost me £9.99 and the finish is horrible for a complete metal calliper, its accuracy is anyone's guess, it measures 1mm more than it should do and under measures and never reads zero. It has movement and when its "wiggled" in a zero position, the counter on the LCD goes up.

[@warheaven999]

this caliper has problem. If you put it in a toolbox, it will switch on if something touch the button.

[@paulsengupta971]

It takes the same current if it's switched on or off. I'll post a link to AvE's review.

[@3D_Printing]

13:00 looks like a thick PCB board

[@dontes9588]

You can find the INA3221 Arduino Library on github. Here's the link. github.com/switchdoclabs/SDL_Arduino_INA3221

[@RWBHere]

Julian, are you sponsored, or supplied with free items, by alice? Disclosure would be good form. No offence intended; merely asking, so that we know where you stand. Thanks.

[@JulianIlett]

I did once get a free item from Alice, but that was never followed up. It's much easier to just buy the stuff. I do get stuff for free from Banggood now and again. I don't think disclosure is required unless I'm also given money, but I've never asked Banggood for money. To indicate that an item was supplied free of charge, I normally use the phrase "item very kindly supplied by".

[@3D_Printing]

They have not thumb wheel, or locking very basic

[@MikeDesertHunterHale]

use your calipers!

[@mrroobarb]

It's maybe my OCD but that first R100 resistor would be resoldered straight away... kzbin.info/www/bejne/eWKop56lorGKb5Y

[@RaviJani]

Ask seller. He/she will provide code for ina3221.

[@massimookissed1023]

Ravi Jani , I admire your optimism.

[@RaviJani]

Massimo O'Kissed 2 sellers helped me on aliexpress with codes for unusual modules. So yeah trying will help.

[@jort93z]

sellers on ebay are usually quite nice. you can also ask about certain parts and so on.

Ravi Jani try this library github.com/switchdoclabs/SDL_Arduino_INA3221

[@SciDOCMBC]

under the strip of the caliper are interrupted metal strips, cap means capacitive see here kzbin.info/www/bejne/qoW5ZmV6ns2DisU

[@SomeMorganSomewhere]

SSOP = Shrink Small Outline Package

[@karsnoordhuis4351]

Who needs that imperial rubbish? For small stuff i prefer mm. Just take out that button

[@Leadfoot70]

Julian, Here's the INA3221 arduino code: github.com/switchdoclabs/SDL_Arduino_INA3221

[@mrlithium69]

To all you $10 Caliper people: Dont make the mistake I did of buying the METAL calipers without the digital thing. They are complete crap, you are better off buying this plastic one with the accurate digital device than trying to read cheap metal calipers manually.

[@rwbishop]

Get a good pair, Mitutoyo or Starrett, digital, dial (or even old school harder to read vernier) with carbide jaws... take care of them (don't let any batteries corrode), and they'll preform admirably & be passed down for generations.

[@jort93z]

i would just go to a damn store and buy 20$ metal, digital calipers. its really not that much money and they usually last quite a long time.

[@BajanAlan]

Those calipers dont measure with rollers, they use GPS cordinates

[@JulianIlett]

LOL

[@procactus9109]

You talk about the specs as if it means somthing :\ Mentioning any kind of specs from china only make people look a little slow. Unless you are bagging them out that is.

[@beanlets]

A hair in a kit.🆗🆗🆗🆗

[@jimb032]

Best way to check a caliper is to measure a bearing...

[@eddyfontaineyoutu100]

Don't waste your money with those cheap mechanical tools!

[@althds7099]

hieleow