3D Printed Prox Switch Dropper for Mr. Bullet Feeder

NEWER DESIGN now available.    • Optical Sensor for MrBulletFeeder  


A 3D printed part for the Mr. BulletFeeder to use a proximity sensor.

Fusion3D file here: (this is NOT the file you upload to the 3D printing service)
https://a360.co/2QWP0DL

Download .stl file here: https://drive.google.com/file/d/1E1bP...

Upload the .stl file to here for printing: https://print.all3dp.com Use mm for measure and Multi-Jet Fusion as the process. Currently $23.

NOTE: You will have to clean the threads for the sensor with an M18 X 1.0 tap. If you have to drill the hole any, use a 17mm drill. You might can use a 21/32 which is slightly smaller, but the plastic material should work with that.

Rough sketch of electrical hookup https://drive.google.com/file/d/15NnV...

By request I've added a 9mm version. Here's the .stl file
https://drive.google.com/file/d/1VlzQ...

************* UPDATE (17 Jul 2022) *************
Here is the part with the 3D printed threads for the sensor. This is a .3mf file which is a newer, improved version of the .stl files.
https://drive.google.com/file/d/1qoSl...
*****************************************************

Uploading and connections will be the same for the 9mm as for .223
FAIR WARNING: I have not ordered the 9mm version so I can't say with 100% certainty that it will work. But there's very little different, so it should be OK. Price as of 01/20 is $30 which includes black and polish.

Prox Sensor https://www.amazon.com/URBEST-Detecti...

Relay https://www.amazon.com/PACK-AMP-Water...

Use 1/4" push female connectors on the relay

Connect the two Mr. BulletFeeder wires to 30 & 87a on the relay. They should already have the 1/4" connectors from where they were connected to the trip switch on the feeder tube. Doesn't matter which wire to which tab.

Connect the +12 Wall-Wart to 86 on the relay and BROWN on the prox sensor. You can crimp them together in a 1/4" push-on connector.

Connect the -12 Wall-Wart to BLUE on the sensor. Use butt-splicer or solder and shrink wrap.

Connect the BLACK sensor to 85 on the relay with 1/4 tab.

The wires are small, so you may need to solder them to the push-on tabs.

The wall-wart can be 9–12 VDC. The prox sensor will work with less than 9, but I doubt the relay coil would reliably work below 9 or so. If you only had a 6 VDC power cube, give it a try before buying something else. It takes very little current to operate the sensor and relay, so very small power cubes will work.