Highly Liquid Forum facebook twitter google plus rss feed
  #1  
Old 10-21-2011, 05:01 PM
InactiveX InactiveX is offline
Junior Member
 
Join Date: Oct 2011
Posts: 4
Default Alternative Method To Disable Power-Off

I was having some trouble getting my MIDISpeak working in a Speak & Read that I bought. I couldn't initiate the MIDISpeak because the keys wouldn't respond properly. Realising that the key lines 1 and 3 were causing the problem, I disconnected them. This, however, resulted in the S&R powering down after a few minutes (the power save feature). So I deduced that 1 and 3 control the MIDISpeak's disabling of the automatic power down.

After poking around in vain for suitable pins to connect lines 1 and 3 to, I decided to try something else.

I built a circuit that would disable the power down itself, without lines 1 and 3 needing to be connected. An astable was constructed using a 555 timer, which controlled an LED. The LED was set to flash for five seconds every minute or so.

Whilst poking around earlier, I had realised that pins 3 & 4 on the keypad connector in my S&R would simulate a "#/Module Select" keypress. This was a key that, if pressed, would not interfere with the MIDISpeak's operation. Knowing this, I placed a light-dependent resistor across pins 3 & 4.

The LED was placed next to the LDR, and shrouded in black tubing to prevent light getting in. This formed a vactrol, used to simulate the # keypress when the LED is lit every minute or so.

The Speak & Read stays on and all the buttons work. Everything is powered by the S&R's batteries.

I can now rock out on my S&R all night long.

(Well, for longer than 4 minutes, anyway. )
Reply With Quote
  #2  
Old 10-26-2011, 04:31 PM
John's Avatar
John John is offline
Moderator
 
Join Date: Jan 2009
Posts: 3,007
Default

Hi InactiveX, welcome and thank you for this contribution.
Reply With Quote
  #3  
Old 12-13-2011, 09:43 AM
InactiveX InactiveX is offline
Junior Member
 
Join Date: Oct 2011
Posts: 4
Default

Cheers John!

Here's a diagram of the circuit:



R1 = 68K
R2 = 680K
C1 = 100μF
C2 = 0.01μF

As described above, the LED should be placed next to a light-dependent resistor. The two pins on the LDR should be connected to pins on the Speak to simulate the keypress (this will vary between versions - you will have to poke around to find a keypress that is suitable and doesn't interfere with operation).

It is fine to use the standard Speak battery power (6V) to power the circuit.

Last edited by InactiveX; 12-13-2011 at 10:06 AM.
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 04:53 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.