1st time on DCG Project

Dichromated Gelatin.
Zeta
Posts: 42
Joined: Wed Jan 10, 2018 9:30 am

Re: 1st time on DCG Project

Post by Zeta » Tue Feb 13, 2018 10:52 am

I already replace the power supply to 5v 10A 50w and power it direct to the controller let it warm up 1 hour pass it's hot (+-40C I think) (heatsinked) but still nothing. Then I take analog readings
pin9-pin14 = 0.23v
pin9-pin4 = 3.8v
pin9-pin5 = 0.02v
pin9-pin6 = 3.88v
pin9-pin7 = 0v
pin9-pin12 = 0v
pin9-pin15 = 0.23v
try connecting pin 1 to 11 to enable the interlock!
Is it ok to use paper clip? Or how should I do that.

pluto
Posts: 97
Joined: Fri Feb 05, 2016 2:06 am

Re: 1st time on DCG Project

Post by pluto » Tue Feb 13, 2018 1:17 pm

Zeta wrote:I already replace the power supply to 5v 10A 50w and power it direct to the controller let it warm up 1 hour pass it's hot (+-40C I think) (heatsinked) but still nothing. Then I take analog readings
pin9-pin14 = 0.23v
pin9-pin4 = 3.8v
pin9-pin5 = 0.02v
pin9-pin6 = 3.88v
pin9-pin7 = 0v
pin9-pin12 = 0v
pin9-pin15 = 0.23v
try connecting pin 1 to 11 to enable the interlock!
Is it ok to use paper clip? Or how should I do that.
Ideally you would use a cable like this: https://guideimg.alibaba.com/images/sho ... 13280.jpeg

But just find something that will hold for a few minutes.

Pin 14 (Power Monitor Output) at 0.23V of 5V (or 3.8V?) should mean 2.3 to 3mW power output.

By the way, the fact that you're getting 3.8v instead of 5v as your TTL high is slightly concerning... I would check that your PSU can supply 5v under load.

It doesn't seem right to me that your controller is getting that hot either :/ Somebody who has owned one of these lasers might be able to step in here.

You didn't get the reading from pin 13 -- this is an important one because it'll tell us what the controller is set to output.

Divide your reading by 5 then multiply by 50 to get the setpoint value.

Hard to get a good reading when you're getting 3.8v instead of the stated 5v... It seems to me that you should be getting 5V when taking readings from the controller -- this might be a big deal.

Zeta
Posts: 42
Joined: Wed Jan 10, 2018 9:30 am

Re: 1st time on DCG Project

Post by Zeta » Mon Feb 19, 2018 11:27 am

I think I will buy a new one from sam's laser.
And how thick should my emulsion be?

pluto
Posts: 97
Joined: Fri Feb 05, 2016 2:06 am

Re: 1st time on DCG Project

Post by pluto » Mon Feb 19, 2018 1:25 pm

Zeta wrote:I think I will buy a new one from sam's laser.
And how thick should my emulsion be?
When starting, don't worry about that. Just heat your glass plate and emulsion to 40c to start and veil coat. You don't really even need to spin it to get a decent result.

Once you get a hologram, then you can start tightening up your process.

Zeta
Posts: 42
Joined: Wed Jan 10, 2018 9:30 am

Re: 1st time on DCG Project

Post by Zeta » Mon Feb 19, 2018 3:06 pm

Has anyone ever tried silkscreen technique for coatings?

pluto
Posts: 97
Joined: Fri Feb 05, 2016 2:06 am

Re: 1st time on DCG Project

Post by pluto » Mon Feb 19, 2018 4:28 pm

Zeta wrote:Has anyone ever tried silkscreen technique for coatings?
Zeta, please try this if you can.

I'm very interested in alternate coating techniques, as coating plates is currently one of the most tedious and unreliable parts of holography for me.

Some form of spray-coating would be great as well. If the gelatin could be atomized and sprayed onto glass in very thin layers anyway, not sure if this is possible.

A thread about novel coating methods would be great :)

Steven
Posts: 37
Joined: Sat Jan 31, 2015 8:14 pm
Location: Cornwall, UK

Re: 1st time on DCG Project

Post by Steven » Tue Feb 20, 2018 12:33 am

pluto wrote:coating plates is currently one of the most tedious and unreliable parts of holography for me.

A thread about novel coating methods would be great :)
I totally agree.

Coating is the most difficult, soul destroying and frustrating part of DCG.

I find that casting (mould coating) to be consistent, but I'm having problems with the dreaded bubbles since returning to holography.
I'm getting less than 50% success rate at the moment due to bubbles, but I've not had problems with the gelatin pealing off the glass.

Steven.
Success through failure - the amateur DCG holographer's path to enlightenment.

Steven
Posts: 37
Joined: Sat Jan 31, 2015 8:14 pm
Location: Cornwall, UK

Re: 1st time on DCG Project

Post by Steven » Tue Feb 20, 2018 1:06 am

Zeta wrote:I think I will buy a new one from sam's laser.
And how thick should my emulsion be?
You are measuring the output of your power supply off load - laser not connected.

I also suspect that the power supply you are using has a remote voltage sense capability.
The way you have it connected at the moment, it is sensing the voltage at it's output terminals, rather than at the laser analogue controller.

Remote voltage sensing will ensure that you have +5 Volts at the analogue controller - it takes care of any voltage drop on the cable.

Please refer to your instruction manual that came with the power supply for correct wiring.
If you don't have a manual/instructions, do a google search using make and model number of the supply.

If you refer to the manual on the laser (link posted above by admin_jsfisher) you will see that you don't need anything connected
to the 15 pin D connector to enable the laser. You just need the two pins of the Autostart Function connector shorted out, which you did.

The fact that the yellow/amber LED is illuminated on the laser head tells you that the laser (pump diode) is on!
You are just not getting a full +5 Volts on the analogue controller.

Steven.
Success through failure - the amateur DCG holographer's path to enlightenment.

Zeta
Posts: 42
Joined: Wed Jan 10, 2018 9:30 am

Re: 1st time on DCG Project

Post by Zeta » Tue Mar 06, 2018 11:20 pm

Hello

I have done a lot of veil coating but the result was vary, what a good coating should look like?
I got dim transparent yellow, super transparent yellow(no picture), cloudy crystal.
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S__24870964.jpg (479.54 KiB) Viewed 4159 times
About laser I increase output from power supply to 7v and now pin 4 is 5v but still nothing.

pluto
Posts: 97
Joined: Fri Feb 05, 2016 2:06 am

Re: 1st time on DCG Project

Post by pluto » Wed Mar 07, 2018 1:51 am

Zeta wrote: About laser I increase output from power supply to 7v and now pin 4 is 5v but still nothing.
You should have found an appropriate power supply. The voltage only drops from 7V to 5V under load. There will be times, even if brief, that this load disappears. Then you get 7V pumping into this precision laser driver -- not good. I don't even trust the mains voltage going into my laser power supplies. I highly recommend using a voltage regulator and surge protector to power your laser systems. Small price to pay for peace of mind!

I suggest you chalk this up to experience and just buy a complete laser system.

If you're willing to pay shipping both ways, I wouldn't mind trying to get it working. If it works, I ship it back, but otherwise I keep it for evil experiments :)

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