GCA124 FREDI

By Peter Giling

LocoNet® is a trademark of Digitrax, Inc.

Description

Olaf Funke designed a nice FREDI for Fremo.

It is a professional set-up, in a way that the design is based on the use of many smd components.

These components are undoubtly perfect for the job, but for the home hobbyist very difficult to put together.

At least, that was my opinion.

So, now with the permission of Olaf, I redesigned the unit using only one SMD component.

A small other difference is the fact that I aborted the possibility of installing a normal potentiometer.

So only the modern incremental switch as used in many central units like Intellibox and CSI/II is possible.

Any questions about this FREDI, please contact peter@phgiling.net .

I'll be very happy to help you out.

This hand held throttle is very well supported in Rocrail.

For a small fee Fred Jansen is prepared to program an Atmega8L for you.

The schematic	mgv124-sch.pdf
The PCB design	mgv124-pcb.pdf

Qty	Reference	Description	order nr
2	R1,R2	12 E
3	R4,R6,R32	47 K
1	R5	100 K
1	R7	2K2
3	R8,R9,R12	470 E
1	R10	4K7
1	R11	10 M	see assembling info
1	R13	68 E
1	R31	82 K
1	C1	ELCO 22 uF 25 V radial
5	C4,C5,C10,C11,C13	100 nF
1	C6	47 pF
1	C7	ELCO 10 uF 25V radial
1	C12	1 nF
2	C2,C3	15 pF
1	C8	10 nF
2	Led1,Led2	LED 3mm green
1	Led3	LED 3mm red
3	D1,D2,D3	DIODE BAT85
1	T2	BC337-40
1	IC1	ATMEGA8L8
1	IC1 socket	Dil-28 small
1	IC2	LF 33cv 3,3 V regulator TO220	Reichelt LF33CV
1	J1	Connector SMD RJ12 6PC	Conrad 741513
1	S2	Encoder EC11 with push switch	Darisus EC11E15244
6	S3,S4,S5,S6,S7,S8	Tact switch PC horizontal	Darisus DTS65N
1	Q2	CRYSTAL 7,3728Mhz
1	ICSP1	header 2×3	Conrad 742499
1	Box	Housing	Reichelt SP 2090 SW
4	self tapping screws	2,9 x 6	Reichelt SBL 2965
1	knob
1	bolt M3 x 8
1	nut M3

For the fimware, I have to refer to the original FREDI site.

A few remarks have to be made to help you being succesfull with the production of this FredI.

Fix the empty PCB with screws in it's future housing, and use it to drill the exact positions of the pushbuttons, SW2 and leds.

Use the pcb as a mould for holes of pushbuttons, leds and SW2.

All other parts can be mounted after that.

The pushbuttons and leds are mounted at the backside of the PCB.

Please take care not to use the center hole of the leds, because that one is only a drilling mould.

After a serious check, connect the pcb , without IC1, to LocoNet. Check if 3,3 volt is correct between pt 7 and 8 in IC1 socket.

As far as my experience has gone, R11 can be omitted.

Should you have any misfunctioning, the resistor might help.

If you can not find it there, contact Peter.

For setting up a Fredi in Rocrail look at: setting up a loconet slotserver
Let the Interface ID in the loc setup empty: LocDialog Interface Tab
Fill in the LC IID and the DP IID in the : Rocrail general Tab
Fill in the IID of the Command Station that controls the locs (LC IID) : Loconet Interface Tab
Check the: Use mode column for dispatch
Tell the desired loc to dispatch, look at : Throttles