Machdyne AF

Overview

Machdyne AF is an open-source project for a PNP autofeeder system¹.

The autofeeder design is a closed-loop system that uses an infrared LED and phototransistor array² to precisely detect the tape position. The tape is moved forward using a geared DC motor and a sprocket. The cover tape is partially separated and advanced with the tape.

The autofeeders can be chained together with 4 wires and communicate with the system controller using the I2C protocol.

The system uses two custom printed circuit board designs. An autofeeder controller PCB (Essen) includes the tape detection and motor driver circuitry for each autofeeder. A system controller PCB (Koch) provides power and allows a chain of feeders to communicate with the OpenPnP software over a USB-C port.

Autofeeder 3D parts (AF1)

Model	Image	Description
af		The autofeeder body guides the tape and holds the Essen PCB in place
af_sprocket		The sprocket advances the tape
af_motor_lock		The motor lock holds the motor in place
af_blade		The blade partially peels the clear film from the top of the tape to the side
af_led_block		The LED block holds the LED in place
af_lid		The lid closes the autofeeder and guides the tape

Bill of Materials

Part	Quantity	Description	Example P/N
Worm gear motor	1	Right-angle N20 DC 12V 16 RPM	JGY-N20
LED	1	3mm 940nm 1.3Vf Infrared LED	DY-FIR204C
M3 bolt 12mm + nut	1	for blade	-
M3 screw 20mm countersunk	1	for LED block	-
M3 bolt 20mm countersunk + nut	3	for lid	-
M3 bolt 25mm	1	to connect LED block to rail
M3 T3 nut	1	to connect LED block to rail

You will also need dupont jumper wires to connect the motor and LED to Essen.

Assembly Instructions

Cut, strip and solder one end of the jumper wires to the motor leads and each lead of the LED. Press the LED into the LED block, and run the wires through the large LED block hole.

Attach the blade using an M3 bolt and nut.

Press the sprocket onto the motor axle. Press the motor into the motor cavity.

Run the LED wires through the rear autofeeder hole and connect to Essen LED_A and LED_K. Connect the motor wires to Essen MOT1 and MOT2.

Push the PCB onto the PCB notches so that it locks into place.

Attach the LED block using the screw.

Place the motor lock on top of the motor.

Attach the lid.

Connect Essen to Koch or other Essens using a 4-pin female-female 2.54mm dupont cable.

Attach the LED block to a 2020 rail with an M3 bolt and T-nut.

The assembled autofeeder (without lid):

Autofeeder controller PCB (Essen)

Also see the firmware and usage instructions.

Pinout (Rear)

9  7  5  3  1
10 8  6  4  2

Pin	Signal	Notes
9/10	12V	System power input
7/8	GND	Ground
5/6	SDA	I2C data
3/4	SCL	I2C clock
2	TRIGGER	Optional external tape advance signal
1	SWDIO	MCU SWD signal for firmware updates / serial debugging output

Pinout (Top)

Pin	Signal	Notes
1	MOT1	Motor driver output #1
2	GND	Ground
3	MOT2	Motor driver output #2
4	GND	Ground
5	ELED_A	External (IR) LED anode
6	ELED_K	External (IR) LED cathode

The motor driver can drive one bidirectional motor or two unidirectional motors.

System controller PCB (Koch)

Also see the firmware and usage instructions.

Pinout

1 2 3 4

Pin	Signal	Notes
1	12V	System power output (2.5mm positive tip)
2	GND	System ground
3	SDA	I2C data
4	SCL	I2C clock

Funding

This project is being partially funded through the NGI0 Entrust Fund, a fund established by NLnet with financial support from the European Commission's Next Generation Internet programme.

License

This project is released under the CERN-OHL-P license.

Footnotes

1. This project is still under development and is not yet suitable for use in production. ↩

2. While the PCB has an array of six phototransistors, the firmware is currently using only one. ↩