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Topic: USB Cable suitability (Read 1 time) previous topic - next topic

aisc

I bought a Type A - Mini USB cable on eBay.
Turns out to be a skinny cable, like for mobile phones.
The ones I get with an Arduino board are usually quite fat.

Just wondering how suitable it would be for long term use with an Arduino.
FWIW I bought it to power a programmed Arduino from a USB wall-wart.

Zapro

We cannot answer that for you.

Test it out! - If it works as intended and the voltage delivered at the Arduino isn't too low, it's fine.

It isn't going to break on it's own just because it's skinny. It will break if you flex it a lot.

// Per.

Paul__B

Well now there are two sides to this question.

Literally.

We are mostly looking at the resistance of the wires.  The capacitance may also be a concern for the data connections but that probably is nothing near a limiting factor.

So.

The resistance of the data wires is unlikely to be a concern.  That leaves only the resistance of the power wires.  This should not be a problem if you are only using a few hundred milliamps.  If you were going up into the Amps range, then it might be.

I am using a couple of those 50 cent ("noodle") cables here, so far no troubles, but have not put them to extreme testing.

be80be

#3
Sep 18, 2015, 02:06 pm Last Edit: Sep 18, 2015, 02:12 pm by be80be
I guess none of you have a smart phone just kidding but my phone charger cable is small and it's for data two
but the charger is a fast charger 1500 mA and I have one that was rated for 2200 mA for a hot spot charger.
Both are small cables the hot spot one is 4 foot long the phone one is 3 foot, I buy these cables when I find them cheap yard sale goodwill places like that I have only found maybe one out of over 20 that had small power wires. I've found smaller wires in the bigger older cables that came with printers and stuff like that.

Why they have there own power so size doesn't tell you much here. The softer ones last longer cost more but if its for a cell phone you can be sure it's made for a 1 to 2 amp. 
On a side note I got one for my car it's flat 6 foot long and said it's rated 2 amps but it never fast charges my phone even though my car has a fast charger.

aarg

On a side note I got one for my car it's flat 6 foot long and said it's rated 2 amps but it never fast charges my phone even though my car has a fast charger.
Some fast chargers work by shorting the datalines. The phone senses it and knows from that that it's okay to draw more current than the USB spec.
  ... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.

be80be

Good point I new that lol but still good point. You don't see that much as you did. These new phones suck all they can get. That's why some don't work with older chargers

aisc

#6
Sep 18, 2015, 03:37 pm Last Edit: Sep 18, 2015, 03:50 pm by aisc
We cannot answer that for you.

Test it out! - If it works as intended and the voltage delivered at the Arduino isn't too low, it's fine.

It isn't going to break on it's own just because it's skinny. It will break if you flex it a lot.

// Per.
Voltage is not dependent on the cable. Voltage is dependent on the wall-wart, except for voltage drop, which in this case will be negligible given the cable is only 30cm long.

Zapro

Voltage is not dependent on the cable. Voltage is dependent on the wall-wart, except for voltage drop, which in this case will be negligible given the cable is only 30cm long.
I know that.

What i meant is if the voltage is too low, the resistance of the cable is too high. Go figure!

I have seen USB cables 50cm long with a huuuuuuuge voltage drop with a 400-500mA load. Some of them is just crap!

// Per.

DrAzzy

#8
Sep 18, 2015, 06:45 pm Last Edit: Sep 18, 2015, 06:46 pm by DrAzzy
I've seen two classes of unusable USB cables:

Charging-only cables. Occasionally marked with a battery symbol. These may have the power lines shorted together, or they may be connected to voltage dividers hidden in one end of the cable (to make a "stupid" charger charge a pre-lightning Apple device at full speed). Chargers exist that do various permutations of things to the data lines as well, for the same reason. 

Crap cables with insanely high resistance across power and ground. I've measured 5 ohms on a fairly short cable, while trying to figure out why it would only feed my phone 100mA. Well, that'd to it! This is just the manufacturer cheaping out and providing a useless product as a consequence.

The thickness of the cable is mostly from insulation and shielding - the thick cables have gotten less common, as customers seek out thinner, more portable cables, and manufacturers are likewise eager to use less raw materials.
I don't know if the flat cables actually are fragile, but they *feel* very flimsy - that flat cable concentrates the strain on the edges of the cable where it meets the connector, and it's preference for certain orientations (due to it not liking to flex along one dimension) makes them difficult to work with and puts stress on the thing they'rep lugged into. I avoid them whenever possible.
ATTinyCore and megaTinyCore for all ATtiny, DxCore for DA/DB-series! github.com/SpenceKonde
http://drazzy.com/package_drazzy.com_index.json
ATtiny breakouts, mosfets, awesome prototyping board in my store http://tindie.com/stores/DrAzzy

aisc

I was concerned about the mention of certain issues as relates to charging cables.
On the one hand the item I bought is listed as a charging cable:
Quote
New USB Short 2.0 A Male to Mini 5 Pin B Data Charging Cable Cord Adapter
On the other hand the specs indicate it is a USB spec cable:
Quote
Description
100% Brand New and High Quality
Color: Black
Length:50cm
New generic USB 2.0 Cable, Type A to Mini 5-Pin Type B
Quantity: 1
Transfer images and data between your camera / cell phone to computer by USB port
Connectors: USB to Mini USB 5-Pin
USB 2.0 specification, Hi-Speed transfer rates up to 480Mbps
PC and Mac compatible

Package Includede
1 x High-speed USB A Male to B Mini 5 Pin Sync Cable
A quick resistance test between the pins in the Type A plug revealed no shorting, so for now I will assume that to be the case. I need to find some USB sockets with tails so I can measure the resistance.

Anyway, since the issue of special circuitry in chargers was mentioned, I bought one of these power supplies to be used in conjunction with the cable to power the Arduino. Now I am wondering if I need to have concerns about the power supply itself.

Any thoughts?

CrossRoads

Only the long shipping time from China.
I picked up a phone charger at a local outlet resale store (Ocean State Job Lot) that I use. I also have a USB power brick from Radio Shack, and one from Staples.  Pick one up locally, save yourself a few weeks.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

DrAzzy

You don't need socket to test resistance of a micro-usb cable - connect one of the probes (via cliplead if your probes don't have a clippy end) to a sewing needle, and then you can touch the pins inside the micro-usb end with it.
ATTinyCore and megaTinyCore for all ATtiny, DxCore for DA/DB-series! github.com/SpenceKonde
http://drazzy.com/package_drazzy.com_index.json
ATtiny breakouts, mosfets, awesome prototyping board in my store http://tindie.com/stores/DrAzzy

aisc

@CrossRoads : Noted. FWIW I ordered it a few weeks ago and already have it.

@Dr Azzy : I need 4 hands :)

I did try it earlier, with one end plugged into a Nano and got 2 Ohms.
Anyway tried it again direct and still get 2 Ohms on one pin and to 3 Ohms on the others.

The mini plug is so small, it is hard to see which pin is which, so at this stage not sure of the pin-to-pin connections. However, I was surprised to note there is no connection between the housings at either end.

larryd

No technical PMs.
If you are asked a question, please respond with an answer.
If you are asked for more information, please supply it.
If you need clarification, ask for help.

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