[sdiy] Monitoring my Dotcom system's supply voltages

[Jean-Pierre Desrochers]

> this thread begs the question: why?
> I'd say get a good power supply and trust it.  no?

Simple reason:
Anything goes wrong (voltage dropping because of any shorts) with the normal 
Supply lines
---> I'll see what VCC line is in trouble (panel led OFF) and fix it faster.
I will also set the threshold to around 0.10v below a normal supply line.
Ex: Lower than +14.90v on the +15VDC line will shut the led OFF on the 
+15VDC led panel.
JP


----- Original Message ----- 
From: "Giorgio" <dancemachine at gmail.com>
To: "nicolas" <nicolas3141 at yahoo.com.au>
Cc: "Synth DIY" <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, September 13, 2012 11:30 PM
Subject: Re: [sdiy] Monitoring my Dotcom system's supply voltages


> this thread begs the question: why?
> I'd say get a good power supply and trust it.  no?
>
>
>
> On Sep 13, 2012, at 8:10 PM, nicolas <nicolas3141 at yahoo.com.au> wrote:
>
>> Simple comparators will show you overall sag, but a bigger problem in a 
>> synth is noise, spikes, hum, transient glitches, etc.  So some way of 
>> detecting any small AC component on those lines would be very useful, 
>> which could be low freq hum or audio crosstalk or hi freq digital 
>> crosstalk or broad spectrum noise or RF interference.  And also a way of 
>> capturing very brief excursions (+ve and -ve) and latching an LED for a 
>> few seconds so that you can see it, in case you are getting transient 
>> spikes or dropouts.  Something that could do all that reliably and simply 
>> would be useful thing to have :)
>>
>> Nicolas
>>
>> ________________________________
>> From: Stewart Pye <stewpye at optusnet.com.au>
>> To: Synth DIY <synth-diy at dropmix.xs4all.nl>
>> Sent: Thursday, 13 September 2012 8:17 AM
>> Subject: Re: [sdiy] Monitoring my Dotcom system's supply voltages
>>
>> If you use a pic you'd still have to divide down the input voltages. I'd 
>> probably just use a single voltage reference and a quad comparator. You'd 
>> have to put a voltage divider on all the inputs you are measuring, but 
>> the voltage reference can be used for all inputs if the voltage divider 
>> for the negative voltage is an inverting amplifier. That's only 6 or 7 
>> resistors (plus the LED current limit resistors) 1 voltage ref, 1 op amp 
>> 1 quad comparator. You may even be able to get away with using a quad op 
>> amp for the comparators + op amp.
>>
>> Alternatively use two voltage references, or invert the positive one with 
>> an op amp.
>>
>> Regards,
>> Stewart.
>>
>>
>>
>> On 9/13/2012 1:35 AM, Jean-Pierre Desrochers wrote:
>>> Good point André,
>>>
>>> I've been browsing around lots of analog solutions
>>> so far ending with voltage refernces + voltage comparators
>>> + a bunch of passive components..
>>> I'm starting to think of a digital solution (!!)
>>> Just a simple Microchip PIC with analog inputs
>>> could do all the voltage checks, hysteresis and
>>> leds driving for my 3 voltages, and that in one chip.
>>> The -15v will even be monitorable with some tweekings..
>>> I already have a +5v to supply it without
>>> disturbing my +/-15v lines with digital spikes..
>>> Hmmm, the only problem with micros is futur repairs (in the next xx 
>>> years)..
>>> Much easier to replace analog parts than programmed PIC's.
>>> I'm still doing some searchs..
>>> JP
>>>
>>>
>>>   On Wed 12/09/12 11:55 , Andre Majorel aym-htnys at teaser.fr sent:
>>>> On 2012-09-12 09:13 -0400, Jean-Pierre Desrochers wrote:
>>>>
>>>>> Here what I found by chance:
>>>>> http://www.reuk.co.uk/TL431-Battery-Voltage-Monitor.htm
>>>> This thread on sci.electronics.components may be of interest :
>>>>
>>>> http://groups.google.com/forum/?fromgroups#!topic/sci.electroni
>>>> cs.components/uDYcuMy4RYQ
>>>> What I got out of it is that using a TL431 with less than 3 µF
>>>> between anode and cathode is asking for trouble.
>>>>
>>>> -- André Majorel 
>>>> http://www.teaser.fr/~amajorel/_______________________________________________
>>>> Synth-diy mailing list
>>>> S
>>>> ynth-diy at dropmix.xs4all.nlhttp://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>>>
>>>>
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