'LIGHTWAH'

[deadastronaut]

yeah i hear ya!....detachable for lighting conditions...(i have one of those book reading clip on leds)

hmmm i need more coffee too...

[Gurner]

ok had a think....oh no you say...

the light wah is fine for all light conditions as its adjustable.......but not when its dark!..(i know obvious)

any weird and wonderful ideas?....

Neither weird nor wonderful...but a practical solution would be to use amplitude modulation. Basically, a carrier signal drives an infrared LED ....your foot,a paddle...whatever, reflects this infrared light back onto an LDR....you then amplify the rx'ed signal & then filter out the carrier, which only leaves you with the 'control voltage' - this method stops ambient light affecting the results.

The first hit google threw up after typing the above is this (which goes into more detail) ... http://ikalogic.com/ir_prox_sensors_40khz.php

[deadastronaut]

hmmm...hi gurner.

wouldnt that be just be on and off action though?...rather than a swell and fall of the signal..wah?..

[Gurner]

hmmm...hi gurner.

wouldnt that be just be on and off action though?...rather than a swell and fall of the signal..wah?..

No it's not an on/off switch, it's a swell control voltage...up/down.

The pickup (LDR) circuit would receive the 'carrier' signal (large magnitude carrier if your foot is close, & obviously small magnitude/none if your foot is far away)....what you end up with once you filter out the carrier is a DC level which directly relates to how close/far your foot is away from the light source/sensor....but ambient light would not (siginificantly) affect this resulting DC level

You then use the extracted DC level as a control voltage to control whatever you wish.....wahtastic.

[deadastronaut]

right...gotcha!...gonna need a bigger boat box then ..

so the range could be adjustable then?..edit: scratch that...  read it...

[Gurner]

so the range could be adjustable then?..

Not sure I understand your angle ....you end up with a DC level directly proportional to how close your foot/hand/wife is to the light source/sensor (whcih obviously must be colocated)...How 'large' that DC level range is in reality, can be massaged with an amplifier & or a Pot. You may even be able to buy a solution in an IC (I've not checked) which handles all the carrier generation/demodulating (TV remotes?)

[deadastronaut]

i'm not letting my wife near it...


hmmm...ok, i get it now, sort of....i know the ir sensor is on the bottom right of that schematic...

but what is..

w4
w3
w1
w2...  

sorry man, just new to sensors/IR...  

please dont say this needs a 555....@#$%ing ticking..

[Gurner]

It's not clear to me either (it looks like an edge connector feeding stuff onto the circuit perhaps?)

Anyway, here's an easier on the eye implementation...

http://freecircuitdiagram.com/2010/04/25/infrared-ir-proximity-distance-sensor/

(as it goes you could use a 555 timer as the carrier .....Tick-tastic! Fortunately, at 40khz-50khz you won't hear the ticks!)

[deadastronaut]

ARGHHHHHHHHHHHHHHH............

ive spent ages on getting my lfo just right avoiding a 555 at all costs......

ive got so many projects that 'tick' i feel like a @#$%ing clockmaker....


anyway, that original sensor looks cool, works even in sunlight/dark etc and importantly adjustable......i just looked at some simpler ones, but they say they still react to ambient light....hmmmmm......

[artifus]

maybe an optical filter over the ir leds to block as much ambient light as possible?
http://www.pixiq.com/article/create-your-own-ir-filter

[Gurner]

maybe an optical filter over the ir leds to block as much ambient light as possible?
http://www.pixiq.com/article/create-your-own-ir-filter

That wouldn't work here...the ambient light causing the problem is the 'IR'  component contained in the ambient lght ....all you'd be doing with an IR filter is blocking the non-IR ambient wavelengths (which aren't the problem anyway) & still letting the ambient IR through (which is causing the grief) along with your wanted IR...so you're no further forward.

[deadastronaut]

hmmmm....

this guy gets his simple one to work in the dark too....schematic link in info...

but its on/off....not up down....cool though.......hmmm....

http://www.youtube.com/watch?v=sR0uQbD6D2E&NR=1

[deadastronaut]

ultrasonic?....

[deadastronaut]

right ok, had a think about this...the ldr side of it is ok really...coz when in dark situations you just flip the lfo wah on....simple..(i'll give IR  a go soon though i fancy..could be handy for other stuff too.. cheers Gurner for your ideas! and patience )

and after all i wanted this to fit in a 1590b!....it has 4 pots now.....speed,depth,sensitivity,volume...

i used one half of a tlo72...(didnt have an 071)...same size anyway...(if anyone has any ideas for the unused opamp they are welcome to add it ok )

the one and only tiny niggle that gets me is when i turn the sensitivity full, it gets brighter and brighter as it should, but on the very last bit 'full turn' it cuts off the led?...should i use a log maybe?...hmmm..

so here is the final 'LIGHTWAH' shematic...untidy i know but hey...this is how it is!..and it works fine!......anyone fancy a weekend 1590b pcb designing project?...




\m/         \m/     

[arma61]

so here is the final 'LIGHTWAH' shematic...untidy i know but hey...this is how it is!..and it works fine!......anyone fancy a weekend 1590b pcb designing project?...

..probably not for the weekend...... but in the near future!!      

[deadastronaut]

^ dont be lazy...

[Gurner]

Just one small bit of feedback .....it's that little more difficult to establish quickly what's what in your circuit (not impossible, just a bit more time consuming) due to using an actual opamp package in your schematic vs a normal opamp symbol .

You'll probably get more input from others if they don't have to go & seek the connectivity out. Ok, so TL074s are very common and probably most on here know which pin is which off pat, but it still helps with the overall flow of the eye to use symbols in a schematic (as you have with the resistors, caps, trannies etc) for the ICs too.

That said...good show....as the saying goes "the boy done well!" (nice playing too ...even if I could design the best effect ever to be made - it would sound like sh*t when I demoed it!!)

[artifus]

i used one half of a tlo72...(didnt have an 071)...same size anyway...(if anyone has any ideas for the unused opamp they are welcome to add it ok )

i vote envelope detector. maybe take a look at nurse quacky.

infra red wise i stumbled upon this recently. not cheap. but there are some d-beam like schemes out there also.

[askwho69]

rob the half t072 can be use as bias? example connect the pin 5 to 9 volts and connect the 6 and 7 pin and output voltage is pin 7  = biased i got it from the uproar schematic from madbeanpedals.com

by the way the wah is very fantastic rob its super.. this well be the time to build this circuit.. but... i was very confused on how they work?

"Questions"
wrapped heat-shrink - lfo  LED and LFO LDR?
Wrapped Heat-shrink - Footwah led and foot Ldr or "IF" we put it in the enclosure this 2 components should be outside the enclosure?

so the external LED = d3 is just a indicator for the LFO right?
How about the d1? i dont get the idea how the LED light and turn on and off? relly horrified me


Lastly what Transistors did you used?

[arma61]

Hi m8s

here is the redrawn schematic (with the right symbols!  ), if someone can check it for me (values... connections...) I may go on with a PCB layout.



Here is a direct link, I dont think the above image is clear enough
http://i256.photobucket.com/albums/hh174/arma61/LIGHTWAH2.jpg

and here is the link to the ExpressSCH .sch file

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=45544&g2_GALLERYSID=c7b201ca6db94acce063954cb4826147


Thx

btw rob I like your guitar tuner! ! ! !