[time-nuts] TASS Computer-Controlled Switch System

Tom Van Baak tvb at LeapSecond.com
Wed Sep 30 05:23:47 UTC 2015


John,

Thanks for making this available. I can only imagine the amount of work that went into it. Having used many of the same HP RF GPIB switches as you over the years to do multi-device routing and timing, the TASS geometry is very clever; several steps above what HP did. The decision to use the Arduino shield form-factor is spot on. I suppose we are all now imagining multiple layers of Time & Frequency shields.

The first person to put a sub-ns PICTIC II on a shield gets a special prize.

A year ago I thought this was just a T&F project but I see you neatly evolved it to a generic ham tool as well. Hopefully that community will help make this a success.

One question -- because of cable or load changes do you see any noise or disturbance on the first or second reading after you change the switches? Also, what's the rated lifetime of the switches?

Thanks,
/tvb


----- Original Message ----- 
From: "John Ackermann N8UR" <jra at febo.com>
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>; <volt-nuts at febo.com>
Sent: Sunday, September 27, 2015 7:19 AM
Subject: [time-nuts] TASS Computer-Controlled Switch System


> Every so often, I hijack the list to do some shameless self-promotion 
> when I think it would be of interest to the 'nuts community.
> 
> I've spent the last several months developing a computer-controlled 
> relay switch system.  The impetus was failure of the old HP 59307A GPIB 
> switches in my PPS measurement system and discovery that replacement 
> relays are unobtainium.  The only similar remote switches I could find 
> cost >$1K, which seemed a bit rich.  So, I decided to roll my own.
> 
> We ended up with an 8 port switch board controlled by an Arduino.  I 
> think it will have lots of T&F applications as well as usefulness in ham 
> shacks.  Like virtually everything I do, it ended up as a TAPR kit.
> 
> There's an introductory video at https://youtu.be/P-TUM2dOi4c
> 
> The relay board kit is $119 and we have a shield for the Arduino Mega 
> 2560 that can control 4 relay boards and costs $19.  The software is 
> open source.The boards are now available from TAPR at
> http://tapr.org/kits_tass.html
> 
> (BTW, I contribute my designs to TAPR and don't have any financial 
> interest in sales.)
> 
> Special thanks to time-nuts Bob Camp and Tom Holmes for a lot of 
> engineering assistance.
> 
> Here's the TAPR product announcement:
> 
> "
> Now Available: The TASS Computer-Controlled Switch System
> 
> The TASS (Totally Awesome Switch System) is a general purpose 8 port 
> DC-150 MHz relay-based switch. The hardware is designed to be very 
> generic, with an inexpensive processor such as an Arduino providing the 
> system logic. Control is via USB, with ethernet and other interfaces 
> also available.
> 
> The TASS can be configured several ways, and multiple boards can be 
> combined to create large switching systems. The TASS has many uses, from 
> switching signal sources on a test bench or in a laboratory, to 
> selecting receive antennas and filters in a ham or SWL station.
> 
> The TASS system has two boards:
> 
> *  The TASS-R relay board, which does the mechanics of signal switching 
> and provides a very simple 10-pin interface.
> 
> *  The TASS-SHIELD board for use with an Arduino Mega 2560 
> microcontroller. The TASS-SHIELD allows up to four TASS-R boards to be 
> controlled simultaneously.
> 
> Both boards are available now from TAPR as kits.  They use through-hole 
> parts and don't require any special assembly techniques.
> 
> The final component is open source software for the Arduino that acts as 
> an interface between a host computer or other input system, and the 
> switching hardware.  The software is available for download from TAPR.
> 
> 
> An introductory video is available at
> https://youtu.be/P-TUM2dOi4c
> or from TAPR at
> http://tapr.org/~n8ur/TASS/TASS_Intro_26Sep15.mp4
> 
> Software and documentation can be downloaded from
> http://tapr.org/~n8ur/TASS.
> 
> You may order the TASS-R and TASS-SHIELD boards by visiting
> http://tapr.org/kits_tass.html
> "
> 
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