Infinium optical faders

Parts Questions
1

Did anybody tried optical faders from Infinium. They are comming with 45, 60 and 100 mm travel. Somwhere I noticed they are starting from around 7$ which is really cheep. What makes them really kool is posibility to adjust its tension! :slight_smile: Check out  their page: http://www.infiniumtechnologies.com/categories/products

What worries me is that they give 0-3V analog output which is not enough to drive multiplexers. I guess some simple amp would do the job. What do you suggest.

I see Mackie d2 are using Infinium faders
d2_crossfader_lg.jpg

2

The order form says that even the 45mm ones are almost USD$30 each. If you can find them for $7, please let me know where!

3

Hm, wellā€¦ I see yesterday something like starting fro 7$. Maybe it was kit, and assembled 30$. Annyway, I like those. So is there a easy way to integrate it?

4

Personally, Iā€™d use the SPI output and not bother going via ADCs

5

What worries me is that they give 0-3V analog output which is not enough to drive multiplexers.

ā€¦ they have also digital output and they are not cheap http://www.midibox.org/forum/index.php?topic=6462.0

Greets, Roger

6

Ok, they are not cheep but 30 bux for fader of that qualityā€¦ I think it`s fair. And you probably wont ever need to replace it.

Here is the reply from Ian from Infinium

Hi Sasa,

I am the applications engineer here at Infinium, and you can contact me for any questions or support that you need on the faders.

Our analogue output is generated from a PWM circuit on the fader and so it needs to be buffered before it can be used. I am attaching an application note that shows this. We have a number of other outputs available digitally (selected by options) from SPI to serial. Would these be of any use to you. Also we are always keen to hear of other outputs and applications where a change to the design might help you to use the fader, so perhaps you could give me some more details or things to look at that might be useful to you.

We are currently testing a fader with a higher output voltage, however it would still require buffering in your design because it has a high output impedance.

The simplest solution would be to add a small opamp configured for non inverting gain of 5/3 which would bring the voltage up to the required level and act as a buffer. You should look at amplifiers with low offset to get the best performance. If you need any help with a design for this please let me know and I will see what we can do to assist.

Best Regards

Ian Holmes

And here is the document atached to the mail: http://www.bgprodavnica.com/temp/AN-01.pdf

Seams not problem to have 0-5V analog output, but what do yoiu think/sugest about integration into MBox. What kind of Opamp use for it`s buffer?

7

Why do you want to use analog control? Whatā€™s wrong with SPI/Serial? Itā€™s easier, cheaper, more accurate (Doesnā€™t go through two stages of ADC/DAC), saves pins and is far more flexible, especially in the case of incremental mode (the faders can be relative or absolute, which would be very handy for xfading and other more specialised fading tasks)

Maybe Infinium will cut a deal if we can get some more buyers? I know that orders over 100 need an RFQ, so I would assume a price break. Also, Iā€™d say we would all be capable of assembling them, and the site mentions that they are cheaper when bought unassembled.

8

Why do you want to use analog control? Whatā€™s wrong with SPI/Serial? Itā€™s easier, cheaper, more accurate

Because I know how pot and encoders are working, and how to connect it. SPI/Serialā€¦??? What the hack is that and how to implement it in the mbox? I read their info but dont understend much. And as you probably know I cannot do eny code customisation. If it is simple connecting a wires or changing few noumbers in code I am in, if I have to right my own supportā€¦ I give up.

Maybe Infinium will cut a deal if we can get some more buyers? I know that orders over 100 need an RFQ, so I would assume a price break. Also, Iā€™d say we would all be capable of assembling them, and the site mentions that they are cheaper when bought unassembled.

That would be great. I guess asembling wouldn`t be the problem, even there are some SMD chips.

9

I think itā€™s more mechanical assembly than electronic, but I could be wrong about that. They really are light on data on that website, they say thereā€™s a datasheet, but stuffed if I can find it!

SPI is a serial protocol similar to IIC (like the bankstick). The ā€˜serialā€™ mode will be something similar, and will probably be very close to IIC. It will be proprietry so weā€™d need the datasheets to find out if theyā€™d be useable, and how much (if any) code mods would be requiredā€¦ Could you ask your contact for a full datasheet?

10

sure, I mailed them for datasheet and asked about details on bulk order.

11

I think itā€™s more mechanical assembly than electronic, but I could be wrong about that. ?

ā€¦ I think itā€™s electronic. I was talking to them early this year because I showed interest for using them in our mixers.

In our conversation he mentioned, that it would be cheaper for us if we include their electronics right on our fader boards.

Funny thing is, they just E-mailed me about an hour ago and asked me if Iā€™m interested in samples  :slight_smile:

Greets, Roger

12

Here is the news from the Ian from Infinium

Hi Sasa,

The old datasheet has been removed from the server, but here is some info that may be useful from the customer section of the website.

It is for the 45mm standard fader, but most of the info also applies to the 60mm and 100mm parts. The resolution on the absolute fader, with standard res is 64 steps per 22.5mm as a rule of thumb. We have a higher resolution part in development at the moment that achieves 2 to 4 x  this.

You can down load an overview of the fader from the website, and the schematic attached shows you the pinout of the unit.

regards

Ian

And here is the provided PDFs

schematic http://www.bgprodavnica.com/temp/DX400211.pdf

and drawing http://www.bgprodavnica.com/temp/45mm%20linear%20control%20outline%20drawing%5b1%5d.pdf

About price I get reply from Reneā€¦

Dear Sasa,

Please find attached our pricelist which gives you prices for mechanics only

(CKD) and the fully assembled fader for the three different sizes.

Note that the delivery times mentioned in the price list are for 45mm only.

If you are interested in 60mm and 100mm than I will provide you with

specific delivery times for these products.

Kind regards

RenƩ

prices: http://www.bgprodavnica.com/temp/Infinium%20UK-EUR%20pricelist%20060627.pdf

13

Heya, Nice one Sasa. Infinium seem to be really cool about this too, props to them hey! Clearly they stand by their mission statement of making a revolution in controllers :slight_smile:

I guess that price list explains why you saw a $3 price - thatā€™s for lots of 1000 or more, unassembled! doh! 100 of them might be possible, who knowsā€¦

Interesting to see the data on the unassembled units though. Very interesting. With those schematics, itā€™s easy to see how the optics and electronics of the faders work. Obviously the yet-to-come models increase the density of the sensors and add more rows (more IR) I also notice that the ā€œserialā€ interface referred to on the website is in fact I2C, which is great news for us.

Do the unassembled kits come with the full set of ICā€™s as well? and optics? Or just the mechanics? We could easily deal with construction and our own PCBā€™s if we could just make it a bit more DIY friendly and use DIP ICā€™s. Itā€™s a shame our friend the PIC16F88 only has 7 ADCā€™s or we could use that to drive the IR LEDs and do DAC work, but an 18F452 would do it, and is fast enough and has enough IO pins to drive a few of the faders from a single chip. I would be surprised if they would release enough info to program your own IC, but it might be worth askingā€¦ Otherwise the IC they use is available in PLCC28, we could use a socket for that, but that could bump the price up a fair bit. And then thereā€™s the price of buying a programmer for the ICā€™s, having PCBā€™s made, and a lot of time to investā€¦ I reckon youā€™re better off buying them pre-assembled for DIY stuff, unless maybe it could be done in lots of at least 100, preferably much more. And all that is assuming the optics are included.

Thereā€™s no doubting that theyā€™re a really cool product but I donā€™t know if the benefits outweigh the cost, at least in the DIY sense :frowning:

14

Thereā€™s no doubting that theyā€™re a really cool product but I donā€™t know if the benefits outweigh the cost, at least in the DIY sense

For me DIY on first place doesnt means cheap, it means custom. I am sure lot of us here would like to have optical faders at least one for crossfader. Its not like I am earning big money and want to use all high quality parts. My sellary is only 250 EUR per month and I am always suprised when somebody from normal countries reather buying cheep and ugly few cents buttons than good ones priced few bux. We are building it for ourselfs! Lets build it better and CHEAPER than comercial product. But, that is my opinnion. Im sure Im not the only one. 

15

The beauty: [link]http://www.mackie.com/home/showimage.html?u=/products/d2/images/d2_crossfader_lg.jpg[/link]

16

Hi,

Iā€™ve just discovered midibox & am planning to build a controller for DJing.

The infinium faders sound great.

I would rather use one of these than a standard fader for wear & tear reasons.

I do a lot of scratching & dont want to replace the fader every few months.

I was wondering if anyone has integrated one into their controller yet.

Any info on how to do so would be much appreciated.

cheers

bozak

17

Hi bozak

The Infinium faders are nice and what I like, is the adjustable tightness of the slider.

But what is it really what makes a quality linear fader get worn out? - Is it the taper? No, itā€™s the slider part. The slider does not work smooth anymore and gives the user a ā€œbad feelā€.

But exactly this part will be worn out with Infinium faders too. And I still didnā€™t see the 1024 step resolution type around yet. The available type has a resolution of only 128 steps.

Iā€™m not shure about the wearing out of the taper in DJ use, since the fader gets used much more often and heavyer than in a conventional downmix situation.

ā€¦ just a few thoughts to think about.

Greets, Roger

18

Hi Screaming_Rabbit,

I havenā€™t had the chance to use an Infinium fader unfortunately.

The main reason I am thinking of using one is for taper wear.

On any mixer I have ever used, it is the taper that has worn out, resulting in the sound bleeding through.

Sometimes only lasting a matter of a week or two before this happens.

I could just use a cheap alps fader like this

http://uk.farnell.com/jsp/Passive+Components/Resistors,+Thermistors+&+Potentiometers/ALPS/RS4511110K/displayProduct.jsp?sku=1191727

but am worries in wont last long.

can you or anyone shed some light on alps faders lastablility?

or maybe recommend a decent fader for scratching?

cheers bozak

19

can you or anyone shed some light on alps faders lastablility?

I donā€™t know for DJ use. Last year I did some tests with the high quality Alps Master fader by using a crank arm. The fader was loaded by about one stroke per 2 seconds. After 6 hours the fader was kind of blocking in a way, that the arm almost couldnā€™t move the fader anymore (the motor was a pretty strong gear motor).

When I stopped the load and continued after about 10 minutes, the fader was easy use again like before.

Now, DJing is a much heavier load than a stroke every 2 seconds, but the problem was not the taper.

I think the faders you used were carbon tapers (much cheaper) and not conductive plastic.

Greats, Roger

20

Iā€™ve just discovered midibox & am planning to build a controller for DJing.

Welcome aboard dude. What software will you be controlling?

I do a lot of scratching & dont want to replace the fader every few months.

If you really do a lot of scratching I think youā€™d be used to that by now! :wink:

I was wondering if anyone has integrated one into their controller yet.

Nope

Any info on how to do so would be much appreciated.

Youā€™ll need to write a serial buss driver for it. Itā€™s SPI-like from the massive 2 seconds I looked at it.

But what is it really what makes a quality linear fader get worn out? - Is it the taper? No, itā€™s the slider part. The slider does not work smooth anymore and gives the user a ā€œbad feelā€.

I donā€™t agree on this frontā€¦ I think thatā€™s maybe true on a mixing desk, but when it comes to turntablism the audio goes to @$^& a long time before the feel of the faderā€¦ Although often you get a ā€˜crunchy spotā€™ where you can feel the damage that makes the fader noisey/leaky/drop out. Itā€™s meost often due to corrosion and the big one is dust/grit. Tiny bits of dirt get in there and because the fader is moving fast, they punch holes in things when they hit.

But exactly this part will be worn out with Infinium faders too. And I still didnā€™t see the 1024 step resolution type around yet. The available type has a resolution of only 128 steps.

I dunnoā€¦ Because thereā€™s no electronics near the slider rods you could keep them really heavily lubed up. The 256 step version is out, but the 1024 one is still a rumour for now.

Iā€™m not shure about the wearing out of the taper in DJ use, since the fader gets used much more often and heavyer than in a conventional downmix situation.

Most turntablists use the upfaders almost as much as the xfadersā€¦ Which always makes me wonder why ppl only talk about fast xfaders around here!

On any mixer I have ever used, it is the taper that has worn out, resulting in the sound bleeding through.

Usually thatā€™s the wiper (that contacts the taper) getting bent up and contacting two points on the taper at once.

Sometimes only lasting a matter of a week or two before this happens.

Thatā€™s a crap fader. Iā€™ve seen turntablists absolutely abuse new faders for a few weeks solid with no rest and they were only just starting to go funkyā€¦

can you or anyone shed some light on alps faders lastablility?

Not really. This question is often asked and never answered. Iā€™m sure you will hear a few "I use this one and itā€™s quite good but (Iā€™ve never had any others to compare it to) / (Iā€™ve only compared it with this one other model..) and a few ā€œthis one has good specsā€ (infinium)

Someone needs to be a pioneer and do some research, talk to numark and technics and such, find out what they use, what their tech is, spend on an infinium or two to test it out, do homework on lubrication and cleaning/foreign object protection, try it with different DJā€™s to get different styles on it, put it all together, and become ā€œthat guy who busted his chops for months and finally found us the best DIY DJ faderā€ :slight_smile: Until then itā€™s voodoo :frowning:

If you decide to be that guy, just remember that DJ audio mixer faders are log curve, not linear, so they arenā€™t usable in a midibox. Or maybe you want to pioneer a log - linear conversion circuit, so peeps can just drop in their favourite mixer fader ā€¦

I bet youā€™re wishing you didnā€™t ask right now huh :wink: