Power supply bus - voltage dilemma

[midnight (Darrin)]

Rowland, I'm a big fan of putting MKT or tantalum capacitors on power supplies to help in rejecting supply noise. This noise could come from the power source if it is a switchmode or possibly even back fed from the devices themselves.

Also, I use LEDs to provide me with a visual indication of whether a supply is healthy or not and found that I needed upwards of 2k Ohm to reduce the brightness of the led for a dark sky adapted eye. you'll be very suprised how bright an LED is with the typical 15-20mA current often quoted in various literature. 5mA would be sufficient for dark/outside applications.

Please see attached my post re noise rejection on a smps I used for a Canon DSLR.

http://www.iceinspace.com.au/forum/s...423#post932423

A power box is certainly worth the effort and tidies things up nicely and Brendan has some good pointers.

Darrin...

[rcheshire (Rowland)]

Thanks Darren. Appreciate the feedback. This is becoming more complex than I would prefer and yet to design and make the PCB. Thnk it will be worthwhile and easier to handle the current demands and waterproof. Not sure how the SMPS noise will affect camera operation, it at all. Same applies to the logic board/Arduino. The last time I used the SMPS it was powering a TEC switching a MOSFET. I think the switching introduced noise which really upset the Arduino. Staying away from PWM on the good advice of other members, so hopefuly, no problem. Most plugin supplies are SMPS in any case. Some are smoother than others, I guess...

Rowland.

[Scorpius51 (John)]

Use of Ferrite sleeves/cores on your leads will help suppress switching noise.

[rcheshire (Rowland)]

Thanks John.