Optical hihat controller

[racer52]

If you could get voltage readings on the tip and the ring with a Roland HH pedal (in various positions) I would probably be able to give more help.

I should have access to a VH12 by this weekend for making these readings.. please standby for results

****Update***
I found a 10k potentiometer in my garage this evening.
I hooked the two ends to the Roland TD20 Tip & Ring (TD20 HHCntrl tip and ring each had about 3.4V open circuit to the Sleeve on them from the TD20)

connected the wiper to the sleeve. messed with the HH Offset in the TD20..tadahh!
open to tight closed and variable.

The voltage readings were rather interesting. I am not sure how to duplicate this function without the pot. I'll try to get the data in a table format and post later this week

I will still get the VH12 readings this week too.

[Thurston]

Dimitri-
I'm hoping to use this circuit for my Hi-Hat pedal as well. I found an emitter & detector combo package at Radioshack that works between the red-infrared range (620-980nm) with a peak sensitivity wavelength the same as yours (850nm). The emitter is IR, but I should be able to use a red LED as well. Some of the specs differ from the one you linked to and I was wondering whether or not you think this would work with your circuit.

Specs are:
(Max Voltage) Collector to emitter - 70V
(Max Voltage) Emitter to Collector - 5V
Collector Current - 50mA (same as yours)
Total Power dissip - 150 mW

[dmitri]

Should be fine if it has enough sensitivity.

[Thurston]

Should be fine if it has enough sensitivity.

Using your schematic, could the sensitivity be determined by measuring the voltage (or current) between the (powered) Tip and (grounded) Sleeve contacts of the pedal jack with full visibilty between the LED and phototransistor? If so, do you know what value I should see?

I understand I might just have to play with it to see if it works, but I'm also trying to learn along the way .

[racer52]

Dimitri-
I'm hoping to use this circuit for my Hi-Hat pedal as well. I found an emitter & detector combo package at Radioshack that works between the red-infrared range (620-980nm) with a peak sensitivity wavelength the same as yours (850nm). The emitter is IR, but I should be able to use a red LED as well. Some of the specs differ from the one you linked to and I was wondering whether or not you think this would work with your circuit.

Specs are:
(Max Voltage) Collector to emitter - 70V
(Max Voltage) Emitter to Collector - 5V
Collector Current - 50mA (same as yours)
Total Power dissip - 150 mW

that is the very same part (Radio Shack part #: 276-0142) that I used on this:
DIY Internal Optical High Hat Controller
http://www.youtube.com/watch?v=8UJcKxX7W50

I used dmitri's ckt diagram with the above Infrared set from 'Radio Shack'..Installed the circuit to the nested tubes... see the above YouTube video for demonstration.. it is hooked to a 6V battery and monitored on the output side with an o'scope.

Segment 1 video shows just the nested tube assembly detail:
http://www.youtube.com/watch?v=sZQBkX4SIJs

I do not have a Megadrum but started playing with this in hope of controlling my Roland TD20

[jman 31]

Nice videos man, how goes the TD20 application? Did you ever get anywhere with that?

[Synthex]

Thank you for these videos !!

[racer52]

Nice videos man, how goes the TD20 application? Did you ever get anywhere with that?

No update yet beyond what I Posted: Wed Feb 18, 2009 2:15 pm
Got the flu... maybe some data in the next few days

Thank you for these videos !!

Glad to help!

P.S. You will notice in the videos that this controller is working in ambient light, with no special attention to external light shielding.

[jman 31]

Here is my version based on ideas by racer52 and Poco Askew. It requires etching a very simple pcb. The pictures are HERE

[Thurston]

Dimitri-
Could the 5k6 resistor be replaced with a 10K or with 5k? My local radio shack doesn't carry anything close to 5k6, so I'll be stuck using 2*10K in parallel with 4*150 in series to get 5k6 equivalent . Wiring up 2*10K in parallel at least gets me to 5k. I don't understand how this resistor affects the circuit so I don't know how accurate this value needs to be.