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Old 16th Jul 2017, 12:30 am   #16
Oldcodger
Octode
 
Join Date: Oct 2014
Location: West Midlands, UK.
Posts: 1,109
Default Re: UV Dry Film PCB technique - experiences to date.

Been playing and it's taken more than 30 mins, which forum software does not like.
Found that by playing with set colours, it's possible to invert in Express PCB. DESIGN- then on main menu- select VIEW, OPTIONS/COLOURS. Set tracks & corners ( top layer) to white, and ignore all others. Use colour show options to get rid of green and yellow , and you're left with an inverted design. Copy ( PRTSysRq) to Photodraw, paste, check size ( resize) and paste to the size of print medium you're using. It's possible in the print options to change this/size of printed sheet.
The board is for a 12v SMPSU /4W drive at +/- 1V from car supply. Betsy is being dragged into the 20th century, but as she's got a chipped key system, and Swimbo loves to loose keys, I've decided to change over to a remote system for Swimbo to open doors/boot etc, BEFORE Swimbo locks us out by either loosing my key or locking keys in car. (AGAIN).
Simple idea- car 12v nominal is sent to a 7805 to drop 12v nominal to 5v, then sent to a 5-12v mini SWPSU to get back to 12v . System is set to operate ONLY when ignition is off, as power is sensed by a relay and supply to
remote unit shut off when ignition is on. In truth- I've had a prototype of this running on a bit of vero board, but I've noticed a lot of green on the board, and as I've decided to put it on PCB, with some form of moisture protection, I decided to put in the only on when ignition off option, to protect against any in motion voltage spikes.
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Last edited by Oldcodger; 16th Jul 2017 at 12:43 am.
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