schematics, source code and kit availableTellyMate

A Serial to TV adapter

A simple 'TV Out' module
  • PAL or NTSC Composite Video
  • 38x25 characters
  • Black and White
  • 300 to 57k6 baud (8n1)
  • Optional Autobauding
  • Simple Graphics
  • Double width / height text
  • VT52 + H19 control codes

More pictures...

This adapter takes serial data and displays it on your TV.

There are currently two different TellyMate variants that are ready to buy:

Batsocks TellyMate Shield

TellyMate Shield

Batsocks TellyMate Tiny TTL

TellyMate Tiny TTL

These variants use exactly the same firmware and have identical output circuitry.

If you'd like to make your own, then schematics, source code and pre-compiled .hex files are available for download.



It has a wide range of uses, from a simple debugging tool, all the way to a games console display (erm - possibly).

We use ours as a debugging/logging tool - it's often displayed on our computer monitor as Picture-in-picture whilst we're writing/debugging code.

Because of it's autobauding capability, the TellyMate will happily take its data from sources with non-standard baud rates. That means it can receive data from internally clocked AVRs. Even tiny AVRs without a serial module can be easily programmed to output suitable serial signals. A sample program for a Tiny13 is available to download.

A (very) simple skiing game (T13 + a few buttons) is in the pipeline available for download (Many thanks, Keith!).


Baud Rate

The baud rate is selected by jumper (see the User Guide).

When configured to "autobaud", a power-up or reset will cause the TellyMate to look at the first few bit-transitions in the serial data it receives to determine the baud rate.


The format of the output signal (PAL or NTSC) is determined by a jumper (see the User Guide).

Control Sequences

The TellyMate is easily controlled by a mixture of VT52 and H19 (heathkit/zenith 19) control sequences. Details of these are given in the User Guide

Source Material

All the Source Material is released under a simple FreeBSD style licence. See the code for details.
A couple of (optional) circuits for RS232 signal translation are shown on the schematic.
These resources are available for downloading, below.

Please feel free to make your own version (that's the point of making the source materials available!), but do not use the TellyMate trademark without an explicit license. See the 'About Us' page for details.

How does it work?

An in-depth article covering the design is available in our Read Me section.


circuit schematics

Version Date File Size
1.5 2012-02-05 (PDF file) sch_tm_15.pdf 60.5 kB
1.4 2009-06-20 (PDF file) sch_tm_14.pdf 57.8 kB
1.3 2009-05-20 (PDF file) sch_tm_13.pdf 50.5 kB
1.2 2009-03-17 (PDF file) sch_tm_12.pdf 48.3 kB
1.1 2009-02-25 (PDF file) sch_tm_11.pdf 43.1 kB
1.0 2009-02-06 (PDF file) sch_tm_10.pdf 41.2 kB

firmware (source + hex)

Version Date File Size
1.1.02 2012-02-05 (ZIP archive) 122.9 kB
1.1.00 2010-03-09 (ZIP archive) 122.1 kB
1.0.14 2009-09-05 (ZIP archive) 110.2 kB
1.0.11 2009-06-25 (ZIP archive) 79.5 kB
1.0.10 2009-06-20 (ZIP archive) 79.1 kB
1.0.9 2009-06-09 (ZIP archive) 58.9 kB
1.0.8 2009-05-20 (ZIP archive) 58.4 kB
1.0.7 2009-03-23 (ZIP archive) 57.8 kB
1.0.6 2009-03-10 (ZIP archive) 58.0 kB
1.0.4 2009-02-25 (ZIP archive) 56.5 kB
1.0.1 2009-02-12 (ZIP archive) 47.0 kB
1.0.0 2009-02-06 (ZIP archive) 44.9 kB

example client code

Version Date File Size
1.1.0 2009-03-06 (ZIP archive) 9.5 kB
1.0.0 2009-02-20 (ZIP archive) 9.3 kB

example client code (skiing)

Version Date File Size
1.0 2009-03-13 (ZIP archive) 12.1 kB