MS20 LM324 Question

Tinhorn

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SmoothBore/Arch:

<font color="Red">On the matter of the Quad Op Amp LM324 low power replacement</font>

Hamiltoe (Posted on: 3:34 pm on Mar. 8, 2002)
If you want to use a 9 volt battery and also have extended battery life, you can replace the quad op-amp (LM324) to a cmos version (LMC660 or LPC660 or TS27M4AIN) that is pin for pin compatible and will significantly reduce battery consumption. I think the cost for the cmos chips are around 2 to 4 dollars from mouser or radioshack. The RS part numbers for the LMC660 is 900-6330 and the LPC660 (mil spec/cold weather version is 900-6331).

Brian (Posted on: 10:37 pm on Aug. 18, 2001)
You might check into the micro power op amp from Holtec. The HT9274. It is a pin for pin replacement for the LM324.

<font color="Red">MS20 Schematic</font> (for experimenting with Gain)

I drew up this schematic on the MS20 some months ago, if you can read my Turkey Scratching.  Looks like R13 (1.5M) might set the Gain of that stage.  I left the Drawing LARGE for better readability.  If you can't resize it, let me know

http://www.nightowl.net/~tinhorn/MS20sch.jpg

Also, SmoothBore,  I did some experimenting with taping off the Fresnel Lens and adjusting Sensitiviy Range on the MS20,  GunDocc did the same thing on the Lamson PIR.  You might do a Search and see the reports on these tests, if you're interested.

Tinhorn
 



gizz

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Nice Info Tinhorn. I'd like to modify my MS20 setups for low power use and will look into these options. I was contemplating whether to swap out the MS20 with the Lamson but hate to "break it if it ain't broke" if you know what I mean. I get very good results with the MS20 so extending the battery life may be the way to go.
 

SmoothBore

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Good work guys!
I had a couple of op-amps in mind but your suggestions bear investigation.  Maybe I can obtain a sample or two to do some testing.  I mean hey Arch seems to be pretty good at that! .

FYI, It is difficult to mailorder electronic parts for a reasonable price in my neck of the woods (Shipping is usually double the cost of the components).  So instead of building my own low power PIR, I was just checking to see if could easily upgrade (ie tinker) with the readily available MS20.
 

jayber

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Would the the Holtec HT9274 be compatible with 6V use?  I saw mention of 9V and just wanted to make sure.
 

Brian

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The HT9274 is s 5.5 volt max chip but it is pin for pin compatible.

I can email you the specs on the chip.
 

Tinhorn

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The IC gets it's power from the internal 5v regulator circuit so the input volts can be from 6 to 24 VDC........

I am def interested in making the MS20 more efficient (and adjusting the gain)  I'll have to try it too,  if somebody tries it, be sure and let us know the results!

Donka

Tinhorn
 

Tinhorn

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On the Last Order from Mouser, I purchased one of the PIN for PIN IC's mentioned above and did some testing this Morning,  Here are the Results and general info:

Tinhorn


<font face="courier new">
MS20 Power Current Comparison: (April 29, 2002)

Original IC (LM 324) VS Pin for Pin Replacement Low-Power IC
Op Amp # NJU7024D (Mouser # 513-NJU7024D,  $1.36)

Battery Volts (6v lantern)      5.88 volts


Current:       Idle              LED
 (error, not 64 but 36% reduction)
 Orig IC    1.66 ma's        13.90 ma's   ~64% reduction in Current
 LP   IC    1.07 ma's        17.21 ma's Repacement IC has greater GAIN

I only tested the range at 35' (inside the house, couldn't see the TEST LED outside) and expect the range to be at least as far as the Original IC, maybe even farther, unfortunatly, since the New IC seems to have greater gain (based on the Increase in current when driving an LED)


Battery Life (based on only PIR current)
AA battery, Alkaline,  Battery Ampacity = 2000 ma's

1.66ma's = 50 days or  7 weeks or 1.7 Months
1.07ma's = 78 days or 11 weeks or 2.6 Months


Pin for Pin Comparison of Voltages:

                Original IC                    Replacement IC
Pin       Idle (V)       Tripped(V)        Idle(V)          Tripped (V)

1         4.41            4.31              4.46             4.35
2         2.50            2.50              2.50             2.50
3         2.51            2.51              2.50             2.50
4         5.86            5.79              5.89             5.80
5          N/R            2.09               N/R             2.04
6          N/R            2.57               N/R             2.50
7        ~2.55           Bounced           ~2.51            Bounced

8           0             4.49               0               5.20
9          N/R            2.18               N/R             2.17
10         2.30           Bounced            2.30            Bounced
11           0               0                 0                0
12           0             3.99                0              4.90
13         1.35            1.35              1.34             1.34
14           0             4.52                0              5.75

</font>

N/R means PIR did Not Reset (stayed triggered with meter connected to this pin)
 

Archilochus

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Hi Tinhorn,
One of the STM parts should get you a better reduction in current.
The part you listed has a per amp consumption of 150uA
(150uA x 4 amps = 0.6mA)

The STM parts have a per amp current of about 10uA - they have a really low power model at about 2uA / amp - but I'm not sure of the pinout.
NOTE: Use the TS27"L"04 - it has lower consumption than the "M" series.  It's the part I use in my home-brew detectors.

<<<<EDIT>>>>

BTW... I noticed you show ~5.8 volts at pin #4 (++power) - I thought the circuit had a *5* volt regulator???

<<<<End Edit>>>>

Archilochus

(Edited by Archilochus at 12:13 pm on April 29, 2002)
 

Tinhorn

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Hi Arch,

Just got back from a week of getting skunked Turkey Hunting......

You're right about the MS20 having a built-in 5v reg, it uses one of the IC's op-amps as part of the regulated circuit and a "pass" transistor for the 5v output.  The manufacturer apparently has pin 4 connected to the raw voltage, which was 24vdc when functioning as a flood light.  After the Mods for the camera, pin 4 goes to raw battery volts.  I didn't notice this and will have to see about connecting Pin 4 to the regulated +5 volts on some of those IC's with a max voltage rating of 5.5 volts.  I'll try to do this soon.  I don't know what the Vcc rating is on the chip I got from Mouser, it's a wonder I didn't let the smoke out.  I experimented with a weak 6v lantern battery.....

Thanx for the Info on the other IC.  I was disappointed that the current was only about a 3rd less with this replacement IC

( I made a mistake above when I said the amperage was reduced by 64%,   it's really 36%)

The next time I make an order, I'll try to get one of those IC's, but it may be a while......

Tinhorn
 


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