[GreenKeys] USB interface to ASR Mod 33 Teletype

Sun Jul 29 14:02:21 EDT 2018

Hi John,

I recently built a few of Eric Volpe's boards (from Heepy.net) and have
been writing scripts with which to run my machines from Raspberry Pi. Not
having tried any of the others, I'd highly recommend it. If you're familiar
with writing software for Android to utilize its Linux underpinnings and
drive a serial interface via USB, then I wager you have the skills to
program something to communicate with any of these interfaces. It's
certainly much easier to connect it up to something like a Raspberry Pi or
the like, but it sounds like you might already have a lot of the custom
legwork required to go from an Android device. This being said, I have
utilized my Android phone via USB to both tether my cellular connection to
my Raspberry Pi to provide internet for my teletypes and to SSH into my
Raspberry Pi for control. It's effectively running TCP/IP over USB. Not all
phones support this out of the box, though.

I've very much liked Eric's design. It's versatile and has served me well.
It requires an external power supply, so as long as that's doable, it works
out great. John Nagle has a newer board based on USB rather than RS-232
that uses some clever engineering to power the current loop only using the
5V supplied by USB. That wouldn't work being driven straight from an
Android phone, though. You'd have to pass through something that could
supply the power needed to drive the loop. I haven't yet gotten my hands on
one of these, but I hope to have one soon.

https://github.com/John-Nagle/ttyloopdriver

I have been planning to do a manufactured run of Eric's design for
GreenKeys. However, since I'm preparing for another fair at which to run my
machines in September and then moving into a temporary home while our new
one is being built shortly after, among a dozen other things, I highly
doubt I'll find the time to make it happen until next year.

--Jordan

On Sun, Jul 29, 2018, 6:52 AM john at toebes.com <john at toebes.com> wrote:

> You know, I didn’t get a chance to check the interface before it got sent
> off to Wayne for some needed TLC.
>
> I’m not afraid of building on a proto board, I have plenty of the Adafruit
> proto boards to populate, but I figured I would check with the list for
> advice first.
>
> Thanks!
>
> Sent from my iPad
>
> On Jul 29, 2018, at 8:17 AM, Steve Garrison <steve.n4tty at gmail.com> wrote:
>
> John, I would have to still agree with Dave, but if you could get it to
> work I would think #4 might be your best bet.  Although I have zero
> experience with #2 or #3.  Others with experience with 2 & 3 please chime
> in.
>
> Eric hasn't made any of the #4 board in a good while now so you'll have to
> find someone that would be will to let go of one.  Plus the board was
> designed to use a current loop, so you would have to take that into account
> as well.
>
> And is your ASR 33 setup for current loop?
>
> Steve G./N4TTY
> Sent from my iPhone
>
> On Jul 29, 2018, at 7:31 AM, <john at toebes.com> <john at toebes.com> wrote:
>
> I wouldn’t worry about software for Andriod.. We have that covered, our
> robotics team drives their robots over USB using custom software.  As it
> turns out, WiFi while interesting is not an option as we are not allowed to
> have any WiFi devices at competitions where we would be showing off the
> Teletype.
>
>
>
>    - John
>
>
>
> *From:* Dave Wade <dave.g4ugm at gmail.com>
> *Sent:* Sunday, July 29, 2018 4:24 AM
> *To:* john at toebes.com; greenkeys at mailman.qth.net
> *Subject:* RE: [GreenKeys] USB interface to ASR Mod 33 Teletype
>
>
>
> John,
>
>
>
> I am not sure any of these will work with an Android Phone. The USB on
> Android Phone or Tablet is usually a device port for connecting it phone.
> You can get an OTG cable but then you need software that has Android
> drivers for the serial interface you are using. What software were you
> going to use on the phone to drive the Model 33? My preference would be for
> an ESP8266 board so I could connect vi WiFi but it would need a TTL to
> Current Loop…
>
>
>
> Dave
>
> G4UGM
>
>
>
> *From:* greenkeys-bounces at mailman.qth.net <
> greenkeys-bounces at mailman.qth.net> *On Behalf Of *john at toebes.com
> *Sent:* 29 July 2018 04:22
> *To:* greenkeys at mailman.qth.net
> *Subject:* [GreenKeys] USB interface to ASR Mod 33 Teletype
>
>
>
> Hi All,
>
>   I’m looking at the best way to connect an Android Phone (USB) to a ASR
> Mod 33 teletype.  To the best of my knowledge, I have found 4 possible
> interface circuits:
>
>
>
>    1. http://aetherltd.com/connectingusb.html Connects a Silicon
>    Laboratories CP2102-EB to a second Teletype to RS-232 board (Designed for
>    Teletype Model 15 with Baudot)
>    2. https://trmm.net/Boost_converter uses a Teensy with the Adafruit
>    DC/DC Boost circuit (last update 15-Aug-2013)
>    3. http://avitech.com.au/?page_id=318 is a USB Powered Current Loop
>    Interface (last updated in27-Dec-2014)
>    4. http://heepy.net/images/8/8b/Usbtty-instructions.pdf  /
>    http://heepy.net/index.php/USB-teletype USB Serial Teletype Loop
>    Adapter posted to Greenkeys April 2016
>
>
>
> I’m interested in finding out from people which (if any) people are using
> and what is the most resilient (or if there are other solutions I should
> look at).
>
> Thanks!
>
>    - John
>
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