interfacing a CCS to a pic

[be80be]

It's probably the same stuff just not pure.

 

[large_ghostman]

It's probably the same stuff just not pure.

Dunno Burt, I would use for electronics but not high Vac or dangerous chemistry. With the Dow Corning stuff you know its going to do the job, that alone makes it worth the money at times.

 

[be80be]

Dunno Burt, I would use for electronics but not high Vac or dangerous chemistry. With the Dow Corning stuff you know its going to do the job, that alone makes it worth the money at times.

Your talking about holding a resistor not sealing deadly gas but I'm sure it would do that to after all it's only to keep the O ring from being cut because its dry.

 

[large_ghostman]

Your talking about holding a resistor not sealing deadly gas but I'm sure it would do that to after all it's only to keep the O ring from being cut because its dry.

In the distillation side there isnt any O Rings, you use ground glass joints. Normally depending on what your distilling I use conc sulphuric acid to grease the joint, or if I am pulling a vacuum I use the grease.

But for resistors and stuff, IF I can find some in the UK then it would be worth it. The Dow C stuff comes in a tube 1/2 empty, although you use very little, but a grease that was cheaper would make life easier. The down side is making sure your working clean and tidy. It IS a REAL mare to get that stuff off anything. Everybody thinks you just wipe it off............Yeah try it . You get left with a really stubborn film of it lol.

Then its out with the carcinogens to try and get rid of it!! Even holds up to 15% Hydrofluoric Acid! I havnt got access to anything stronger so cant test with 40%. But most things are eaten alive with 15%. We did have a demo at a University open day, they used 40% Hydrofluoric Acid. That stuff is really evil! Fluorine Chemistry is so interesting, but it is just too difficult to handle. The professor doing the demo's was absolutely fine with NaK, but you could see the nerves on his face with 40% Acid.

 

[be80be]

I see said the blind man

 

[large_ghostman]

I see said the blind man

A blind man stood in the middle of a supermarket, furiously swinging his dog around his head by the tail. A women came running upto him and said, " What the hell you doing with that dog!".

The blind man says " its ok, I am just having a look around " .

Way off topic sorry

 

[JonSea]

...going to call the module supplier on Monday to double check on the module specs and number of recommended lrds etc....

I wonder what the supplier had to say. Probably got confused with "number of recommended lrds, etc....."

I'd sure be surprised if he told MrDEB anything than to drive the input pin directly from a port pin.

 

[be80be]

Yep me too jon I been installing a lot of led lighting and they cut off in sets
Of 3 it using 12 volts with 3 resistor for
Each led they dont hardly get hot

 

[MrDEB]

The basic plan was changed but then back to the 3W leds. This project is for a guy in Florida and different scenarios came up. I suggested going with some led panels w/ 48leds per panel I found on Ebay but he wanted to go with the 3w single leds. I sent him a link about thermal runaway and use of a CCS module. His plan is to have the leds "twinkle" so basically on for 1 second then off for 1 second or there abouts.
I have circuit boards designed and ordered (yes I bread-boarded and tested each section of the project). There are 6 pcboards needed but have 10 total on order. Each board has 20 logic level mosfets controlled by a 18f4321 pic. Using a 10K pull down resistor on each gate. Utilizing the ADC to adjust the flash rate. Have a 4 position coded rotary switch to select which program user wants. The pic is mounted using a 40 pin socket. This way any programming changes can be made by just mailing the pics back to me. After I assemble all 10 boards, will test each one individually. Will send all 10 boards to Florida but only 1 pic. customer can then suggest code changes before I send the remaining 9 chips. Have a-lot of thought into this basically simple project. Hopefully haven't missed anything.
YES thermal runaway is an issue I have brought up several times but customer doesn't want to have to purchase 120 CCS modules. Can't blame him seeing how all the components so far are $360 plus boards. Using the 3W leds from **broken link removed**
he will need to hard wire a resistor per led / string etc.

 

[large_ghostman]

1 sec on, 1 sec off is flashing not what I would call a twinkle....... I am pretty sure you can find pre built panels to do this alot cheaper.

 

[MrDEB]

he wants 20 channels per board. Buying them you lose the versatility of customizing it to your desired needs.
ON/OFF for 1 second I was using as an example. Thinking of using the candle flicker code I put together that works pretty good but using a large led may not be so "twinkly".
Beside whats fun by buying already assemble.

 

[large_ghostman]

he wants 20 channels per board. Buying them you lose the versatility of customizing it to your desired needs.
ON/OFF for 1 second I was using as an example. Thinking of using the candle flicker code I put together that works pretty good but using a large led may not be so "twinkly".
Beside whats fun by buying already assemble.

But isnt that what your customer is doing? I might be missing something, these threads tend to change course quickly and confuse my pea sized brain.

 

[MrDEB]

I just offered my input and remember the customer is right.
I am just producing the boards and let the customer realize what he did was not the best decision.
I can only add my two cents and let he chips fall where they may.

 

[MrDEB]

I suggested to purchase lots of these instead of the 3 watt high powered leds
**broken link removed**

no where near the issue of thermal runaway.

 

[large_ghostman]

This is way beyond my understanding sorry, I dont think I can offer anything of value. I hope you get it sorted, sorry I cant help but I dont really understand alot of the project, so I dont have much to offer with this.

 

[large_ghostman]

None of my business Mr Deb, but a thought occurred to me. I dont know the rules over there, but here you need to be ROSh compliant and meet no end of regulations, you cant just sell something like this without meeting the rules. Be really careful, even in kit form this could land you in serious trouble if you get it wrong. Your rules might be different, but in the UK it isnt as easy to sell stuff like this as you think.

 

[JonSea]

I just

I just offered my input and remember the customer is right.
I am just producing the boards and let the customer realize what he did was not the best decision.
I can only add my two cents and let he chips fall where they may.

When you offered a solution, and then offered to do it for a fee, you represented yourself as an expert to the (obviously new here) poster. You really shouldn't laugh it off and say he made a poor decision. If if you just take his money for the boards, you can't say "Oh sorry, you made a bad choice" when it doesn't work as it should.

If things don't work, you better expect to eat the cost of the boards and all the parts plus anything else you charged him.

 

[MrDEB]

I have tested each code section and they all work as planned. I offered my input for the solution to control the 3W leds.
I don't feel I laughed it off. I have talked with the guy in Florida on several occasions and if the 3w leds don't work as planned then he will go with the 48 leds per panel. He understands that the leds may be short lived but hopefully will use adequate heat sinking.
He understands the 3w leds have a high risk of failing.

 

[large_ghostman]

I hope you have a watertight contract, Check for rules on lead free etc etc. Ultimately its your pom pom's in the wringer if it goes wrong, I am not being a moaner, but with doing anything commercial you got to dot the I's and cross the T's.

Jason from here did alot of background work before starting a business. Let the chips fall, is the kind of statement made by someone with sand in there eyes .

 

[JonSea]

Why do 3w LEDS have a high risk of failing?

The only reason I know they fail is when they get too hot. And why do they get too hot? Improper heat sinking.

As the "expert" in your dealings with the original poster, isn't it your duty to understand what heatsinking is required and to advise him of this??? Proper heatsinking isn't a mystery. If you can't provide proper heatsinking for a 3w LED and you expect it to be a problem ("there's a high risk of fsilure."), why not cut back to a one watt LED in the same package?