Steve2381
Senior Member
Hello all
OK, Starting a new thread on this one.
I work in special effects. Mainly Pyrotechnics, but quite frankly... anything and everything gets built.
It's always last minute, and the deadline is usually yesterday. You have to think outside the box in this field.
I need to design some pcbs that will be as 'multi-function' as possible.
Their use? Anything... and I mean anything. Usually basic timing setup's, or some kind of logic control.
Example... few weeks back, got asked to build a 'Banksy' style picture frame for the MTV awards in Bilbao, Spain..... here it is in action...
All that work for literally seconds in action! We bought a commercial A3 shredder.... threw away 99.4% of it and simply had the paper shredder mechanism with all its safety's removed/cheated. Then a push button operated an 8m2 to time it half way down.
Build a frame with some crap timber from Wickes. Then I took it to Spain!
This week.... 5x 6m flames to fire out of the UK tour War of the Worlds tripod. Love my job!!
Anyway... I digress.
This board ideally wants to be as small as I can get it. I am going to have 08m2, 18m2 and a 40x2 versions.
Lets start with an 08m2.
Supply is nearly always a clean 24v DC.
Input pins will be selectable with jumpers for either 10k multi-turn pots, or as direct signal inputs.
How best to achieve this? My inputs could be any voltage >9v and <30v, so I am thinking of using SOT223 5v regulators as buffers. Will that be OK?
Other option is opto-isolators, but then I need to work out how to use those with varying supplies.
Outputs usually switch SSR's, and they don't need to be on board, but I need to switch in the positive. So I am thinking of switching a BC848 SMD transistor (npn BC548 in SMD) which in turn, switches a MJD127 (pnp TIP127 in SMD).
Basically, SMD versions of what I usually use for my stripboard builds.
5v SOT223 regulator on the input. Breakout header for I2C if I need it.
Header for programming. Jumper to disable the serial input pin and make it useable.
But... not having much SMD knowledge, I am spending forever on Google and Farnell working out what is what.
I have an SMD workstation, and been having a practice.... seems OK.
Is there any hard and fast rules for SMD. There are SO many parts. I am using Diptrace, but the library is really hard to find parts in.
I am basically going down the route of 1206 sized capacitors and resistors for starters, as I don't know any different.
Any pointers.... gratefully received.
OK, Starting a new thread on this one.
I work in special effects. Mainly Pyrotechnics, but quite frankly... anything and everything gets built.
It's always last minute, and the deadline is usually yesterday. You have to think outside the box in this field.
I need to design some pcbs that will be as 'multi-function' as possible.
Their use? Anything... and I mean anything. Usually basic timing setup's, or some kind of logic control.
Example... few weeks back, got asked to build a 'Banksy' style picture frame for the MTV awards in Bilbao, Spain..... here it is in action...
All that work for literally seconds in action! We bought a commercial A3 shredder.... threw away 99.4% of it and simply had the paper shredder mechanism with all its safety's removed/cheated. Then a push button operated an 8m2 to time it half way down.
Build a frame with some crap timber from Wickes. Then I took it to Spain!
This week.... 5x 6m flames to fire out of the UK tour War of the Worlds tripod. Love my job!!
Anyway... I digress.
This board ideally wants to be as small as I can get it. I am going to have 08m2, 18m2 and a 40x2 versions.
Lets start with an 08m2.
Supply is nearly always a clean 24v DC.
Input pins will be selectable with jumpers for either 10k multi-turn pots, or as direct signal inputs.
How best to achieve this? My inputs could be any voltage >9v and <30v, so I am thinking of using SOT223 5v regulators as buffers. Will that be OK?
Other option is opto-isolators, but then I need to work out how to use those with varying supplies.
Outputs usually switch SSR's, and they don't need to be on board, but I need to switch in the positive. So I am thinking of switching a BC848 SMD transistor (npn BC548 in SMD) which in turn, switches a MJD127 (pnp TIP127 in SMD).
Basically, SMD versions of what I usually use for my stripboard builds.
5v SOT223 regulator on the input. Breakout header for I2C if I need it.
Header for programming. Jumper to disable the serial input pin and make it useable.
But... not having much SMD knowledge, I am spending forever on Google and Farnell working out what is what.
I have an SMD workstation, and been having a practice.... seems OK.
Is there any hard and fast rules for SMD. There are SO many parts. I am using Diptrace, but the library is really hard to find parts in.
I am basically going down the route of 1206 sized capacitors and resistors for starters, as I don't know any different.
Any pointers.... gratefully received.