[Heated Bed Ideas & Questions]

Hello

I use peltier elements for some other applications.

It is important to know a couple of things about Peltier elements:

A single module will produce a temperature difference between its 2 sides that is limited (usually around 65°C). This implies that the temperature of the bed at room temp will be limited. The workaround is to stack several layers of elements...

this temperature difference limit also implies that you can't just add 2 aluminium plates on each sides of the elements.

The top plate will heat and the bottom plate will get colder. If you don't "actively remove the cold" from the bottom plate (eg: by warming it with ambiant air), the heating process will stall very quickly.

Another thing is that Peltier elements lifetime is dramatically shortened when driven with PWM. The elements junctions trend to break when subjected to pulses...

Then either you should keep the modules always at a constant full power voltage (which makes accurate temperature control complicated) or drive them with a stable variable linear power supply.

Gael

[Stepper Driver (Part USD1.0) broken. Where to get a new one?]

Hello all,

For information:

I had a look at the Pololu web site. It seems that the "A4983 Stepper Motor Driver Carrier" has been discontinued. The recommanded replacement is now the "A4988 Stepper Motor Driver Carrier".

It seems everyone here has a preference for tht A4983 based board. Why this?

The A4988 seems to have extra short circuit and over current protection.

 

Gael