DIY Thermal LPM for under $50

[TTerbo]

o ok. will the reading still be acurate it will just take idk 30 seconds to read the output?

 

[MarioMaster]

Right, there is no point in adding a capacitor.

 

[lasersbee]

o ok. will the reading still be acurate it will just take idk 30 seconds to read the output?

Maybe longer....


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

 

[Benm]

EDIT: the idea of the resistor is not totally to discard, but only if the resistor is part of the reading head, and if we know the reflective factor of the head .....

It is all about assumptions really. Assuming any measuring device absorbs 100% of incoming radiation is a big step, but not unreasonable unless you have information that proves otherwise.

My idea with the whole concept of using resistors as heating sources was to build something with about 10% accuracy. If you want to go further than that 10%, there are many problems to consider, even the accuracy of your voltage meter if you want to go towards 1% or so.

I still believe a 10% accurate power meter is a valuable asset to anyone experimenting with lasers though... especially since it will show a more-pwer-reads-more-response for tuning systems, regardless of actual accuracy.

 

[kiyoukan]

Now this is something i was looking for.
I too have very many 40mm techs, i read or heard from the voices in my head you can cut them somehow and make them smaller and then re-solder a few points and re attach the wire is this true?
If so we could make 10mm tech or smaller right?

 

[TTerbo]

i hope so please try it

 

[kiyoukan]

I am not going to try until 1. i am am dieing to know a rough power of my new 445nm laser or have some sort of conformation of what i must do in order to make what i have work best.

 

[MarioMaster]

That does work for creating smaller tecs for cooling purposes but the main point here is to get a tec with small junctions and therefore high junction count.

By chopping up a large tec you're still stuck with the large junctions. The TECs are only $15 on mouser...

 

[kiyoukan]

ahh okay, i know their not that much but when you got 9 40mm tech just sitting around you wish you had something to do with them.
So their is no reason to make them smaller like leas surface area to heat up aka quicker readings?

 

[Bionic-Badger]

Think of each of the junctions as a "sensor" that helps you read the data. The higher the density of these sensors, the faster (better?) the reading you can get from them. The higher junction count also increases the cost of the TEC, so getting a smaller one may suit you just based on price alone.

You can buy small Peltier units with all different specifications at Marlow Industries.

 

[Benm]

I suppose chopping one up won't really work, keep the large tec's to do what they were intended for - make a tec cooled labby some day

 

[TTerbo]

i am stillging to start myLPM of with the 40x40mm so i dont mind if it takes a wile to read but will it still be as acurate??
cheers

 

[Bionic-Badger]

i am stillging to start myLPM of with the 40x40mm so i dont mind if it takes a wile to read but will it still be as acurate??
cheers

Well, if you can calibrate it and ensure it's in thermal equilibrium, it should be accurate. It may not be linear though.

 

[HIMNL9]

Now this is something i was looking for.
I too have very many 40mm techs, i read or heard from the voices in my head you can cut them somehow and make them smaller and then re-solder a few points and re attach the wire is this true?
If so we could make 10mm tech or smaller right?

Only if you have a sure way for cut two layers of ceramic without shatter or crack it in any way, and without crack in the process any of the junctions .....

Ceramic plates are bad beasts for work on them .....

 

[TTerbo]

i have finished the case for my LPM(lol) now i am about to etch my board but could you please email me the attachment for the eagle cadsoft layout of that design i will pm you my email. i need it so i can print it out etc. cheers

 

[Things]

Cutting up a TEC will not be easy, infact it will be extremely hard. The ceramic will just shatter. Not to mention you can't really solder to the junctions themselves.