MMDVM board for Arduino Due

To build a multimode digital repeater, G4KLX have developped a complete software called MMDVM (Multimode Digital Voice Modem). It is compatible of main digital modes (to date, C4FM, DSTAR and DMR).

This board interfac on one side transmitter and receiver and, on the second hand the Arduino Due. A computer (such as a Raspberry Pi for example) is connect via USB to the Arduino. This provide a complete controler for numerical repeater.

 

I design this PCB, like some other OM, with components in conventional sizes (DIL integrated circuit, resistors quarter-Watt, …). There is still a quite small component that is the TCXO . To eliminate an CMS component, I chose to install a HCMOS TCXO directly compatible of 3.3V expected voltage of the Arduino. The selected reference is the FOX924B-12 with an announced stability of +/- 2.5 ppm.

I replaced the bulky components (in TO220 housings) with equivalent components in TO92 case. The tests are to be carried out. However, even the largest components can be positioned, as I left the possibility of mounting one or the other versions. The board plugs directly on Arduino Due.

MMDVM board top view with TO220 componentsMMDVM board top view with its components TO92MMDVM board side view, connectors DIN 6 pins MMDVM board side view,with direct connector for receiver and transmiterMMDVM board without componentsMMDVM below the board

In PDF format : MMDVM F5UII v1.1

Here is the BOM

Pos	Component	Value	Précision	Case
1	C1	10µF		D4R2,54_ELKO
2	C2	10µF		D4R2,54_ELKO
3	C3	10nF	10%	3X5R2,54
4	C4	47µF		D4R2,54_ELKO
5	C5	47µF		D4R2,54_ELKO
6	C6	10nF	10%	3X5R2,54
7	C7	10nF	10%	3X5R2,54
8	C8	10µF		D4R2,54_ELKO
9	C9	47µF		D4R2,54_ELKO
10	C10	1nF	5%	3X5R2,54
11	C11	1nF		3X5R2,54
12	C12	470pF		3X5R2,54
13	C13	39nF	5%	3X5R2,54
14	C14	10nF	10%	3X5R2,54
15	C15	100nF		3X5R2,54
16	C16	47µF		D4R2,54_ELKO
17	C17	39nF	5%	3X5R2,54
18	C18	1nF	5%	3X5R2,54
19	C19	100nF		3X5R2,54
20	C20	47µF		D4R2,54_ELKO
21	C22	22nF		3X5R2,54
22	C29	100nF		3X5R2,54
23	C-RX1	Receiver Mini Din		DIN6POL-MINI
24	C-TX1	Transmitter Min Din		DIN6POL-MINI
25	D1	SQUELCH		LED_3mm_vert
26	D2	PTT		LED_3mm_vert
27	D3	POWER		LED_3mm_jaune
28	IC1	LF33CV		TO220
29	IC2	MCP6002-I/P		DIL8
30	IC3	MCP6002-I/P		DIL8
31	IC4	LP2950ACZ3,3		TO92
32	J1	RX TX		Stiftleiste_1x06_G_2,54
33	JP3	GND		Stiftleiste_1x02_G_2,54
34	JP4	5V		Stiftleiste_1x02_G_2,54
35	JP5	TEST		Stiftleiste_1x02_G_2,54
36	JP6	TEST		Stiftleiste_1x02_G_2,54
37	Q1	2N7000		TO92
38	Q2	IRL530NPBF		TO220
39	Q3	2N7000		TO92
40	R1	330		0204_MET
41	R3	4,7K	1%	0204_MET
42	R4	5,1K	1%	0204_MET
43	R5	22K	1%	0204_MET
44	R7	4,7K	1%	0204_MET
45	R8	4,7K	1%	0204_MET
46	R10	220		0204_MET
47	R11	220		0204_MET
48	R12	220		0204_MET
49	R13	10K		0204_MET
50	R14	330		0204_MET
51	R15	47K		0204_MET
52	R16	1M		0204_MET
53	R17	47K		0204_MET
54	R18	5,1K	1%	0204_MET
55	R21	22K	1%	0204_MET
56	R22	4,7K	1%	0204_MET
57	R23	22K	1%	0204_MET
58	R30	100K		0204_MET
59	R98	10K		VISHAY_64W
60	R99	100K		VISHAY_64W
61	TCXO1	12MHz (FOX924B-12)	2,5ppm	CFPX-104
62	X49	POWER		Stiftleiste_1x08_G_2,54
63	X50	A0 A7		Stiftleiste_1x08_G_2,54
64	X51	A8..DAC1		Stiftleiste_1x08_G_2,54

In order to make your copy of the electronic card, you will find here all production files and drilling of the card in standard format Gerber: MMDVM F5UII licensee CC by-nc-sa

Concerning transceivers, I will test the operation with two TM451E Kenwood (transmitter, receiver). This model has an “wide spectral” audio output. Indeed, for the digital radio protocols, you must use the audio output once used in packet radio (AX25) in 9600 baud.

The tests will follow on my blog, in the MMDVM category … Your comments are welcome below.

Here is the board mounted, tested and functional.

 

 

---

If you would be interested to participate in a possible future new grouped order (MMDVM board), leave your email below to be reported!

Email :

Leave this field empty if you're human: