Portable Warning Flasher

I had some self contained 12v LED flasher units left over from an earlier project. They had a 4 wire interface,  12v+ (red), 12v- (black), flash select (yellow) and sync(white).  This model uses one of those self contained flasher units to create a portable battery powered LED warning flasher.  It uses the +/- 12v and flash select wires.    Provision was made for recessed mounting of 32x5mm cup magnets  to allow for magnetic mounting as an option.  Magnets fit into recesses on the slide lid.   The slide lid can be secured via use of an M3 cap head screw.

Power is provided by a single, removable, 18650 battery attached to a DC boost module that increases the 3.7v input to 13v to operate the flasher.   Run time will vary by battery capacity.   The typical 18650 batteries I used were generally capable of 1 - 2 hours of operation of these bright, 12 LED, flashers.

In the operating circuit, a protection board sits between the battery & DC boost circuit.  I did this in case I used an unprotected 18650 battery.  The protection board will disconnect the battery if voltage drops to 2.4v.  If the protection is triggered, or the protection board is in an undefined state, the board needs to be reset.  Although such a reset is usually done by applying a charging voltage to the board output terminals,  I found that  jumpering the protection board negative output terminal to the battery negative terminal would reset the board.   The blue push button accomplishes that using output from the switch on the negative battery lead.  Power must be “on” for the reset to work.

The yellow button jumpers the yellow lead on the flasher to the negative side of the DC boost output terminals, where the flasher black lead is attached. A less than one second contact triggers a change in flasher pattern to the next pattern in the list.

I recommend setting the output on the MT3608 DC boost prior to assembly.   Use a 3.7 ~ 4.2 volt input while setting the board to a 13v output.

I used servo tape to secure the batttery protection board and MT3608 circuit board.  8mm M4 cap head screws were used to secure the flasher module and 8mm M3 flat head screws were used to attach the cup magnets.   

I included a “battery wedge” model.   It can be used to help keep the battery in position in the event the flasher is dropped.

 The 12v flasher used was one of these:  https://www.amazon.com/dp/B09DL6PYNX

The MT3608 DC boost board was one of these:  https://www.amazon.com/dp/B089JYBF25

The battery protection circuit used was this one:  https://www.amazon.com/dp/B093V3D4GB

Battery terminals used were 14mm spring contacts.  An alternative could be 12mm AA spring contacts like these: https://www.amazon.com/10Pairs-Battery-Negative-Positive-Conversion/dp/B09DSQL56P

Push buttons were momentary NO 7mm buttons like these: https://www.amazon.com/dp/B07YDHP3HS

The on/off switch used was one of these:  https://www.amazon.com/dp/B087PYW9BS

Magnets used were 32x5mm cup magnets like these:  https://www.amazon.com/dp/B0D77R1RJG

Fusion 360 source & .STEP files are included in addition to .STL files.