Give an Old TV a Rerun

Get date, time and other info:  Luis Bruno

Parts

• SX video module (SparkFun Electronics #DEV-00749; $35.95)
• Board of Education (USB) - Full Kit (Parallax #28803; $99.95)
• 9V battery (local; $3)

Steps

1. Plug the SX Video Display Module into the Board of Education (BOE) carrier board’s breadboard.

2. Connect three BOE kit jumper wires between the SX Video Display Module’s +5 GND, and Serial pins and the BOE header’s Vdd, Vss, P0.

• SX Video Display +5 -> BOE Vdd
• SX Video Display GND -> BOE Vss
• SX Video Display Serial -> BOE P0

3. Plug the BASIC Stamp 2 module into the BOE.

4. Attach the BOE to your PC and download your program into the BASIC Stamp 2 module. You can find two sample programs inside the SX Video Display Module datasheet published by Hitt Consulting.

5. Attach the A/V RCA cables to the video and audio signal inputs (J2 & J1) of the A/V transmitter kit. Connect the other ends of the cables to your SX Video Display Module. The module’s yellow RCA jack is for video output and the white RCA jack is for audio output.

6. Plug a 9V battery into the BOE.

7. Tune your TV to UHF Channel 21.

8. If necessary, adjust trimmer capacitor CV1 and/or trimmer potentiometer RV2 on the A/V transmitter kit for improving the picture quality. Likewise, you can adjust the sound quality by tweaking the core of the high frequency transformer L4.

9. Your analog TV should now be receiving audio and video signals from the SX Video Display Module with the content supplied by a programmed running on the BASIC Stamp 2 module on the BOE.

10. Try your hand at porting some old BASIC games to the Parallax BASIC Stamp 2 module. See:

ATARI Archives

Sinclair ZX81 FAQ

Amstrad PLC ZX Spectrum Documents

Note:
The SX Video Display Module is capable of displaying 6 lines of text that can contain 16 characters per line. Each character is 8 pixels wide and 8 pixels high. There are several graphic characters that can be used for programming simple games.

Communication with the module from the BASIC Stamp is set for 4800 baud. This translates into approximately 480 characters per second. Therefore, an entire screen’s worth of characters (i.e., 96 characters) will take 1/5 of a second for display.

Character data from the BASIC Stamp is sent as standard ASCII codes (e.g., SEROUT Sout,Baud,[“PopSci”]).

Pixel data (1/4 character size) can be turned on and off with the serial commands “plot” and “unplot,” respectively. For example, SEROUT Sout,Baud,[PlotXY].

The SX Video Display Module character set includes 224 characters and 44 1/4 “pixel” graphics. An audio source capable of 255 tones is also available.

H2Whoa! The TV transmitter kit is designed to work wirelessly, but such use violates FCC regulations. We hacked it instead to create a wired solution that is less likely to cause harmful interference.