I built the renewed sensor circuit today, here's the prototype:
This new circuit uses the TAOS TSL251 sensor, which has these benefits compared to a discrete photo transistor:
- More sensitive to human visible light
- Built in high impedance circuit and opamp, which rules out outside electro magnetic influence (the old photo transistor needed a shielded case to work properly)
- Stable output voltages, fast response, built in protections
- Less parts!
Here a closeup of the sensor:
The circuit works fine till now, but I need to test it with laser reflection of course.
For that I need to create some optical parts: a shaft to only allow the part of view to the sensor where the laser will be reflected, and not the surrounding light.
Only three weeks remaining!!!
This weekend I will attend a retrocomputer event in Holland.
I will use that time to finetune the laserharp software and musical elements.
It's no place to finish the laser assembly. Maybe I can do some of that on this friday before the retro event.
Would be nice to have a place to properly test the laserharp before Cambridge!
If I only had more time...
Fiber optic cable could be used to allow only light from one direction to go into the sensor. However since fiber optic cables tend to be very thin, you could do the same with a rod of plastic that has clear ends and surrounding surface painted or scrubbed to not be clear. That way you create a light channel for the light that comes in.
Does not really help with filtering out ambient light. Only to make light from a specific direction pass to the sensor.
Update: in your video I saw you use smoke machine, and you have to try to get the smoke to rise to be able to get it into the laser beams. An overhead pipe connected to smoke machine, with drilled hole (like that used in certain watering systems) could provide a smoke curtain that drifts down if you hang it above the lasers. Just another idea...
Fiber optic cable could be used to allow only light from one direction to go into the sensor. However since fiber optic cables tend to be very thin, you could do the same with a rod of plastic that has clear ends and surrounding surface painted or scrubbed to not be clear. That way you create a light channel for the light that comes in.
Does not really help with filtering out ambient light. Only to make light from a specific direction pass to the sensor.
Update: in your video I saw you use smoke machine, and you have to try to get the smoke to rise to be able to get it into the laser beams. An overhead pipe connected to smoke machine, with drilled hole (like that used in certain watering systems) could provide a smoke curtain that drifts down if you hang it above the lasers. Just another idea...
Thanks Johan.
Optical fibre cannot be used to my opinion.
The number and angles of the beams is flexible: some songs can be played with 8 beams, some with 10.
So the sensor must see the whole width of the area where my hands will touch the beams.
To way to reach that without letting more than needed ambient light onto the sensor, is to use a shaft:
The shaft will be coated inside with matt material, so ambient light does not reflect on the inner sides of the shaft and reach the sensor. Only the light I want to reach the sensor must be allowed.
Tomorrow I hope to get the complete system running again, with the new laser, new sensor and circuit, new TTL blanking safety circuit, and laptop with software etc.
True, you can just make a shaft like that from any material to limit how light reaches the sensor. You could even use a filter over the shaft that allows certain wavelengths of light to pass while others are blocked. Though that is something I have no information on.
You would have to read up on the physics of color, like why certain material lifts certain photons to a higher energy level, to find the material or layer of materials that will allow your blue laser to pass through and block out all other light in the spectrum of light.
However this might also be unnecessary as white light from the sun for example contains the full spectrum, and might allow ambient light to pass through.
It is probably easier to just calibrate the sensors to react to a specific intensity of light to make sure it reacts only to the lasers and not ambient light.
wavelength filters ( unless off the shelf ) are expensive because they have to be custom made ( I know cos unitl last year we had a division that made them ).
re : I have some reflection of the green laser though, checking what the cause of that is. :
this could be caused by wavelengths generated by the laser being outside the wavelength spec of the filter. Also the way certain filters are made limits them to working between or at specific angles.
Using glass optical fibre brings in many more complications ( and cost ) and using acrylic etc effects optical performance and path.
wavelength filters ( unless off the shelf ) are expensive because they have to be custom made ( I know cos unitl last year we had a division that made them ).
I have a filter that passes the blue and green spectrum, so maybe I will use that with the sensor to make it react better to the green and blue lasers and not to other environmental light sources.
re : I have some reflection of the green laser though, checking what the cause of that is. :
this could be caused by wavelengths generated by the laser being outside the wavelength spec of the filter. Also the way certain filters are made limits them to working between or at specific angles.
I have asked others if it's common, and it is.
I also checked some pictures of RGB lasers with similar dichroic filters, and on those pictures it's clear all leak a bit.
An example - this is not my setup! - (you can see the green light reflected a bit):
Using glass optical fibre brings in many more complications ( and cost ) and using acrylic etc effects optical performance and path.
Seeing your work in progress is inspiring. I have so far not built anything using lasers, but that might change :)
Nice picture to show your rig. I thought you only used Blue and Green lasers, but I see now you are using RGB combination. How precisely can you control the reflection of the beams with that rig?
Seeing your work in progress is inspiring. I have so far not built anything using lasers, but that might change :)
Nice picture to show your rig. I thought you only used Blue and Green lasers, but I see now you are using RGB combination. How precisely can you control the reflection of the beams with that rig?
It's not my setup ;) It's an example of green laser 'bleed' instead of the dichro mirror passing the green laser completely.
Unfortunately it's very hard to eleminate the bleed through the filter/mirror without resorting to custom made filters/mirrors.
It's also nigh on impossible with standard deposition techniques to make a mirror 100% reflective for specific wavlengths. ( we spent over a year trying and at ?5k+ a run it's it's expensive r&d )
You can use a 'light absorbent material' to prevent stray light bouncing around in your case though.
I've played my first (attempt of a) complete song, it's Jean Michel Jarre's Second Rendez-Vous part 3.
Of course it's not finished and the unit will be on the ground, making it more easy to play (have to hold my hands sidewards now).
DON'T MAKE COMMENTS ON MY BELLY! I invested a lot in that! ;)
A video:
Here are some pics of the setup:
I haven't tried Roelofs (roko's) idea yet: using two identical sensors to improve sensor output.
So calibrating is still a pain in the ...
I just have to ask you, what is that display you are using in your spectrum? I have been thinking about replacing the taperecorder with a display, but not yet found any small enough display that has the proper resolution (minimum 640x480).
I just have to ask you, what is that display you are using in your spectrum? I have been thinking about replacing the taperecorder with a display, but not yet found any small enough display that has the proper resolution (minimum 640x480).
The one I use I bought two years ago, so don't know which model that is.
Check eBay, and look for 3.5" tft display.
The one I use I bought two years ago, so don't know which model that is.
Check eBay, and look for 3.5" tft display.
Thank you, that is what I have been doing. Just problem with those I found so far is resolution. Thats why I asked about your model. But no problem. I continue looking. Very cool to see the new blue laser harp in action :)
Thank you, that is what I have been doing. Just problem with those I found so far is resolution. Thats why I asked about your model. But no problem. I continue looking. Very cool to see the new blue laser harp in action :)
I see, I have looked at that, found that first too. But Velesoft told me that resolution needs to be 640x480 or else you risk getting vertical lines skipped on the display. I guess however that there is no harm in just trying it. :)
I see, I have looked at that, found that first too. But Velesoft told me that resolution needs to be 640x480 or else you risk getting vertical lines skipped on the display. I guess however that there is no harm in just trying it. :)
You're right, but the display interlaces, so it's readable, but not so sharp.
I'll do all my development work on it! :o
I hope there is something on the market with higher resolution.
Yes, it is. And no real hurry for me. Wont be now I do that project. So I have time to look around. Can you please check your private messages Bvrstee, I sent you a message regarding that 128K ULA ;)
The laser-unit is 'finished', that means: all parts are ready and assembled.
Now I need to thoroughly test the set, hope to start with that tonight.
Calibration is still not the easiest to do: it's not enough to just work with two sensors, there is still some needed.
But the sensor circuit now only has one potmeter, so calibration is down to it's minimum.
I built in two voltmeters for the calibration process, which also makes the set look awesome!
The blue power led is used to show the sensor output ;)
Let's cut some hole in that case, and I'm ready to come over to Cambridge!
Video's later this evening!
The new sensor circuit:
The eyes of the beast:
Those happy blue numbers (reminds me of something, but I don't need 1.21GW to get this baby flying):
Nice. What is that light that seems to stream from below and up, everywhere you put your hand? additional laser beam? Anyway, at least on cam, it is very impressive.
Comments
This new circuit uses the TAOS TSL251 sensor, which has these benefits compared to a discrete photo transistor:
- More sensitive to human visible light
- Built in high impedance circuit and opamp, which rules out outside electro magnetic influence (the old photo transistor needed a shielded case to work properly)
- Stable output voltages, fast response, built in protections
- Less parts!
Here a closeup of the sensor:
The circuit works fine till now, but I need to test it with laser reflection of course.
For that I need to create some optical parts: a shaft to only allow the part of view to the sensor where the laser will be reflected, and not the surrounding light.
Only three weeks remaining!!!
This weekend I will attend a retrocomputer event in Holland.
I will use that time to finetune the laserharp software and musical elements.
It's no place to finish the laser assembly. Maybe I can do some of that on this friday before the retro event.
Would be nice to have a place to properly test the laserharp before Cambridge!
If I only had more time...
Does not really help with filtering out ambient light. Only to make light from a specific direction pass to the sensor.
Update: in your video I saw you use smoke machine, and you have to try to get the smoke to rise to be able to get it into the laser beams. An overhead pipe connected to smoke machine, with drilled hole (like that used in certain watering systems) could provide a smoke curtain that drifts down if you hang it above the lasers. Just another idea...
Thanks Johan.
Optical fibre cannot be used to my opinion.
The number and angles of the beams is flexible: some songs can be played with 8 beams, some with 10.
So the sensor must see the whole width of the area where my hands will touch the beams.
To way to reach that without letting more than needed ambient light onto the sensor, is to use a shaft:
The shaft will be coated inside with matt material, so ambient light does not reflect on the inner sides of the shaft and reach the sensor. Only the light I want to reach the sensor must be allowed.
Tomorrow I hope to get the complete system running again, with the new laser, new sensor and circuit, new TTL blanking safety circuit, and laptop with software etc.
There is no need for that.
You would have to read up on the physics of color, like why certain material lifts certain photons to a higher energy level, to find the material or layer of materials that will allow your blue laser to pass through and block out all other light in the spectrum of light.
However this might also be unnecessary as white light from the sun for example contains the full spectrum, and might allow ambient light to pass through.
It is probably easier to just calibrate the sensors to react to a specific intensity of light to make sure it reacts only to the lasers and not ambient light.
re : I have some reflection of the green laser though, checking what the cause of that is. :
this could be caused by wavelengths generated by the laser being outside the wavelength spec of the filter. Also the way certain filters are made limits them to working between or at specific angles.
Using glass optical fibre brings in many more complications ( and cost ) and using acrylic etc effects optical performance and path.
I have a filter that passes the blue and green spectrum, so maybe I will use that with the sensor to make it react better to the green and blue lasers and not to other environmental light sources.
I have asked others if it's common, and it is.
I also checked some pictures of RGB lasers with similar dichroic filters, and on those pictures it's clear all leak a bit.
An example - this is not my setup! - (you can see the green light reflected a bit):
That's my point.
are u talking about the light dots on the case at 45 degrees to the filter ?
Yes, it's about the same with my setup, allthough this picture is more clear.
Nice picture to show your rig. I thought you only used Blue and Green lasers, but I see now you are using RGB combination. How precisely can you control the reflection of the beams with that rig?
Games List 2016 - Games List 2015 - Games List 2014
It's not my setup ;) It's an example of green laser 'bleed' instead of the dichro mirror passing the green laser completely.
It's also nigh on impossible with standard deposition techniques to make a mirror 100% reflective for specific wavlengths. ( we spent over a year trying and at ?5k+ a run it's it's expensive r&d )
You can use a 'light absorbent material' to prevent stray light bouncing around in your case though.
I really like the color!!!
I added the galvoscanner to check if it all fits correctly, and it seems to be perfect!
Next (hopefully this evening) connecting it all up, testing the galvoscanner, testing the TTL blanking circuit, testing the sensor circuit, etc...
Video coming up!
Next: testing the TTL blanking safety circuit.
After that: testing the sensor.
And then it's just finising off!
Of course it's not finished and the unit will be on the ground, making it more easy to play (have to hold my hands sidewards now).
DON'T MAKE COMMENTS ON MY BELLY! I invested a lot in that! ;)
A video:
Here are some pics of the setup:
I haven't tried Roelofs (roko's) idea yet: using two identical sensors to improve sensor output.
So calibrating is still a pain in the ...
The one I use I bought two years ago, so don't know which model that is.
Check eBay, and look for 3.5" tft display.
Thank you, that is what I have been doing. Just problem with those I found so far is resolution. Thats why I asked about your model. But no problem. I continue looking. Very cool to see the new blue laser harp in action :)
When I search for 3.5" tft on eBay, I get offer like this at the first results:
http://www.ebay.nl/itm/3-5-Zoll-LCD-Monitor-TFT-Display-PKW-Auto-12V-Ruckparkhilfe-fur-Ruckfahrkamera-/271006918259?pt=Auto_TFT_Monitore&hash=item3f19456673
That's the same as mine.
I see, I have looked at that, found that first too. But Velesoft told me that resolution needs to be 640x480 or else you risk getting vertical lines skipped on the display. I guess however that there is no harm in just trying it. :)
You're right, but the display interlaces, so it's readable, but not so sharp.
I'll do all my development work on it! :o
I hope there is something on the market with higher resolution.
http://www.ebay.com/itm/200658705335?item=200658705335&pt=Car_Audio_Video&cmd=ViewItem&hash=item2eb830dbb7&vxp=mtr
Yes, it is. And no real hurry for me. Wont be now I do that project. So I have time to look around. Can you please check your private messages Bvrstee, I sent you a message regarding that 128K ULA ;)
Now I need to thoroughly test the set, hope to start with that tonight.
Calibration is still not the easiest to do: it's not enough to just work with two sensors, there is still some needed.
But the sensor circuit now only has one potmeter, so calibration is down to it's minimum.
I built in two voltmeters for the calibration process, which also makes the set look awesome!
The blue power led is used to show the sensor output ;)
Let's cut some hole in that case, and I'm ready to come over to Cambridge!
Video's later this evening!
The new sensor circuit:
The eyes of the beast:
Those happy blue numbers (reminds me of something, but I don't need 1.21GW to get this baby flying):
Ow, the numbers mean: 3.2-2.3 > 0; led is on! ;)
Click on the pic!