SSTVCAM

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The Argent Data Systems SSTVCAM module is a self-contained slow-scan television encoder with an integrated digital camera.

PDF Data Sheet

SSTVCAM with camera


Features

  • Scottie 1, Scottie 2, Robot 36 and Robot 72 modes
  • Manual trigger or automatic timed operation
  • 8 frames of non-volatile image storage
  • Character encoder for Scottie modes
  • 60 degree FOV with standard lens
  • 75 mA current draw while transmitting, 3.5 mA idle

Hardware Description

The SSTVCAM board measures 1.5" by 1.28" (38mm by 35mm) and is 0.85" (22mm) high with the camera installed. It weighs approximately 1/3 ounce (9 grams.) At a minimum, the board requires a power supply and connection to the transmitter's microphone input.

Pinouts

Pin Function
PWR Power input - 5 to 12 volts DC
GND Ground
GND3 Ground
SEND Sends or stores a frame
RETR Selects memory retrieve mode
STOR Selects memory store mode
MODE1 Selects SSTV format
MODE2 Selects SSTV format
PTT Open collector push-to-talk output
OUT Audio output
RXD Serial data input (LVTTL) - 3.3v max
TXD Serial data output (LVTTL)
SEL1 Selects memory slot or timer interval
SEL2 Selects memory slot or timer interval
GND2 Ground
SEL3 Selects memory slot or timer interval

Note that while the unit will function with a 12 volt input, higher input voltages may generate excessive heat at the voltage regulator when the camera is operating. A supply voltage of 9 volts or less is recommended.

The GND, RX, TX, and 3.3V pads across the bottom of the board are provided for remote connection of the camera module. Cable length should be kept to not more than a few inches.

Solder Jumpers

Jumper Function
HT Selects handheld PTT mode
SJ1 Increases audio output level
SJ2 Increases audio output level
SSTVCAM schematic

Operation

SSTVCAM sample capture

All of the digital inputs on the SSTVCAM are active low - grounding a pin sets it 'on'. The SSTV format to be used is selected by the MODE1 and MODE2 inputs, as follows:

MODE1 MODE2 Format
Off Off Robot 36
On Off Robot 72
Off On Scottie 2
On On Scottie 1

If STOR and RETR are off, pressing button S1 or momentarily grounding the SEND line triggers an immediate transmission in the selected mode. If STOR is on, a frame will be saved to the memory slot selected by SEL1-SEL3. If RETR is on, a previously saved frame will be sent from the selected memory slot. If both STOR and RETR are on, the unit will operate in self-timed mode, sending frames automatically with a delay between each frame specified by SEL1-SEL3, as follows:

SEL1 SEL2 SEL3 Delay
Off Off Off 0 seconds
On Off Off 10 seconds
Off On Off 30 seconds
On On Off 60 seconds
Off Off On 120 seconds
On Off On 300 seconds
Off On On 600 seconds
On On On 1200 seconds

Character Generator

A 1-line character generator occupies the top of the frame in Scottie mode. By default, this line displays the SSTVCAM version and a frame sequence number. The contents of the line can be changed by sending serial data to the unit through the RXD line at 4800 baud with LVTTL (0 to 3.3v) signal levels. Sending a carriage return or linefeed moves the cursor to the start of the line.

Starting with firmware version 1.2, sending an end-of-text (control-C) signal causes the SSTVCAM to save the current line of text to non-volatile memory.