RASP timer


the programmable timer for m-audio microtrack series


Designed to fit the m-audio microtrack recorder, the RASP timer is a programmable circuit board that mimics the keypress of the standard keyboard of this recorder. Two buttons are emulated: ON/OFF and RECORD.
A rather simple modification of the recorder is required to use this timer (four wires have to be soldered to the recorder's switches, and two to the battery ends). The pin-out of the required connector is described in the RASP tech sheets.

Starting from September 2008 all timer board are delivered with the v.3.0 firmware. This firmware has some new power-saving features, and some simplified programming options. Current boards ARE NOT compatible with the older programming software running on the PC.
And the new programming software IS NOT compatible with the older boards.

The configuration software (firmware v.3.0) offers:
CYCLIC RECORDING (record for xx minutes and pause for yy minutes) with xx & yy from 3 to 999 minutes.
SCHEDULED RECORDING, with up to 24 user-defined time slots of recording in a day
MAX POWER SAVING, delivers a total de-powering of the recorder to maximize battery duration. (see manual for details)
SLEEP function, to skip the number of days you want in your schedule
MIDNIGHT RESET, that resets your recorder at midnight, cutting the power for a few seconds
and more features...

DOWNLOAD the PROGRAMMING SOFTWARE for timer boards of the 3.0 series.

Preparing your recorder


As stated, the RASPtimer acts as a keypress on the recorder, doing as you are there when you are not.
Four wires have to be soldered to the recorder in order to have it ready to fit the timer.
The four wires are those related to the ON/OFF switch, the RECORD button, the BATTERY contacts.
The standard battery in the recorder has to be removed, and external power feed has to be provided. In our deployments, and during development, we used four NiMH 1,2VDC recharcheable batteries, or several more batteries with a 5V ultra-low-drop low-quiescent-current voltage regulator.
This "battery change" is needed as the standard power feed via USB port triggers the recorder ON all the time, and results in a continous 250mA power consumption.

The timer board pin-out


Looking at the timer board as shown in the picture at the top of this page, the user has three ports at the bottom.
Starting from LEFT: 

the first 6 pins belong to the recorder's connector. 
Pin 1: (square soldering): goes to POWER switch Pin 2: (now on round solderings): GND for power switch Pin 3: RECORD SWITCH Pin 4: RECORD SWITCH Pin 5: +5VDC BATTERY Pin 6: GND for BATTERY
notes:
Double check that the connector coming from the recorder has GROUND on pin 2.
Consider that pin 2 and pin 6 (both GROUND) could converge in a single wire and could get ground from anywhere you like on the recorder.

the second 5 pins belong to serial interface (I/O) of the board.
Pin1: TX - goes to pin 3 of a 9pin DB9 female Pin2: RX - goes to pin 2 Pin3: must be shortened to Pin5 of this very same pin-out Pin4: GND - goes to pin 5 of the DB9 Pin5: as above must be shortened to Pin3 of this very same pin-out
notes: Pins 3 and 5 shortened tell the board that a serial connection is going to be attempted. Serial interface on the computer must be set to 9600N81 9600baud, no parity, 8 bit, 1 stop.

the third 2 pins belong to power feed of the system
Pin1 is POSITIVE Pin2 is GND - NEGATIVE 
notes:
never exceed 5.0VDC