Zumspot & MMDVM Demo page


Some information on the Zumspot project & MMDVM demos.

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ZumSpot and MMDVM NEWS:

2017-05-31
Today I received the latest project from the MMDVM team.
It's called the Zumspot Libre Kit and is available from Bruce Given of MMDVM Fame.

Oh...you many be wondering just What is this device and What can it do.

This kit has a UHF tranceiver (10 mW) and a micoprocessor board soldered into a
carrier board with LEDs for status. The micro has a uUSB port that connects to a
Host computer (like a Raspberry Pi) running MMDVM_Host software.
This produces a UHF low-power Hotspot for Digital Voice modes D-Star, DMR, Fusion 
and P25. You can find some info on the kit at the  MMDVM Facebook Page.

This image is from the Facebook page and shows the components provided.
Zumspot Libre Kit
Quoting from a post on the FB page:

Kits comes with 
1. Carrier board
2. Modified 7021 Board with Correct TCXO 
3. Modified STM32F103 board so it will work with 
all USB interfaces.
4. 14 LEDS ( So you can use some colors twice ! )
7 Resistors
6. Bootloader preprogrammed on the STMF103 board
7. Antenna
Cost will be $85.00USD plus shipping
You just need basic thought hole soldering skills

p.s. the kit also comes with a ST-Link device for updating the micro's firmware. 


When assembled it will look like this (mine).
My complete Zumspot
(Right-click and View Image for full size)

It should only take about an hour to solder in the few components. You have twice
as many LEDs provided so you can decide on your choice of colors. 
(More about that later in my hints & notes)

The kit does include some Assembly Instructions (Rev 1.00 May-7-2017).
 Here are some of additional notes from my kit.
  Page 3.1, and page 4: Add jumper to RF7021SE board
  - There are two solder pads that are used as jumpers, bridge the gap on the
   jumper across from the "RXD" label. Circled on diagram page 4.
	 (Also as shown in picture below)
	 
3.2 Install LEDs.
  - The kit contains 7 bags with 2 LED's each. Easy to tell the color on the bags
	with the dot (Yellow, Blue, Green, Red) but the others are labled as
	"P" - Purple, "O" - Orange, and "M" - White (monochrome?)
	
  - Here is what I selected for the color layout:
	1. DMR    - White
	2. D-Star - Orange
	3. YSF    - Blue
	4. P-25   - Purple
	5. PTT    - Red
	6. COS    - Yellow
	7. PWR    - Green
	
- One other thing I added was a rubber pad below the RF board, and small ty-wraps
to hold the end in place. This takes some strain off the connectors.
Zumspot RF pad
		
The STM Micro is already programmed with MMDVM code so its ready to run.
Just connect the uUSB port to a Raspberry Pi with MMDVM_Host and you're away.
This unit will also support the Nextion display (shown on top of a Pi-3).


My final image shows the Zumspot in operation.

Zumspot in operation

Here are some comments about verifying the operation of Zumspot.
When you power on your RPi with the USB connected, the carrier board's PWR LED should light. 
The STM Micro board will light its Green Pwr LED as well. Since the STM has MMDVM 
code it will run that and display a blinking Red led. Blink rate about once per second.
When you start MMDVM_Host, on the RPi, it will connect to the Zumspot board and report like this:
YYYY-MM-DD HH:MM:SS MMDVM protocol version: 1, description: 
MMDVM_HS-ADF7021 20170414 (D-Star/DMR/YSF/P25) (Build: 20:42:31 May  5 2017)

This verifies the MMDVM_Host is talking to the STM Micro and shows the firmware version/date.
At this time the STM Red led should blink rapidly, about 2 times per second.
At idle, the carrier board only has the PWR led lit, but other led's will come on as it's
status changes. If you key your radio the COS led should light and the corresponding
Mode led should also light and stay lit for about 5 seconds after the Zumspot returns
to idle. This occurs even though you may have enabled only one mode.
When the Zumspot transmits, the PTT led comes on, and again the led for the active Mode.



So, if you're just starting out with Zumspot and have no previous experience with
MMDVM, then I recommend you research what others have posted about MMDVM projects.
In particular notes about the DVMega setups which would be nearly identical.
There are a number of SD card images that have been prepared which make it very close
to plug and play.  The only changes to files for the Zumspot compared to a DVMega is
the [Modem] section of MMDVM.ini, since this is an external USB device. 

[Modem]    
# ZumSpot on Pi3
Port=/dev/ttyACM0
TXInvert=1     
RXInvert=0

Good Luck, and Have Fun.
Any Questions should be posted on the MMDVM Yahoo Group.

 


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© 2017 VE1AIC NET  June-2017

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