OK guys, yesterday I got my shielded signal cable, so I could install the new board (Monday I scavenged some silicone for waterproofing), on the one end of the signal cable I have about 3-4cm of jumper wire, and on the other end about 5-6cm, and I shortened the signal cable to 48cm vs the old system of only jumper wires @83cm. AND I tied the shielding wire to the gate, dunno if that was necessary? No spurious firings yet, but, the reed switch is buggered, the switch sticks... if you open the gate slowly and gently it doesn't go off, then with the gate open, you flick the reed with your finger, THEN it goes off, so I'm waiting for my hall switch, and then I'm waiting for transportation. Please have a look at the datasheet for this hall switch tell me if it looks OK, plz

 

I'd say the main concern here is that your circuit is working through a 9V battery, while the hall effect sensor accepts a maximum of 5.5V, other than that, the other thing would be to make sure that the sensor does not consume too much current.

 

I noticed the 5.5v limit, and thought to run it through AUX 3x 1400mAh AA battery pack, and the amperage are

Supply Current IDD
Average: typical 5uA; max 10 uA
Awake: typical 1.2mA; max 2 mA
Sleep: typical 2uA; max 8 uA

Now how do I know what awake and sleep conditions are?

edit this is Vdd = 3V, with 3.6V would it be that much different --- would it be higher or lower ratings with the sightly higher Vdd? I'd guess higher I=V/R and V is higher?

 

@MrChips the example circuit in the pdf I posted asks for a 50k pull-up resistor, would that be maximum current draining component? Will this circuit work with a 1M1 pull-up resistor (the biggest I have). Or does the pull-up only activate when Vout activates (that's what I would guess). And do you have a clue about the particulars of a hall switch, what is awake and what is sleep? Your input would be well appreciated

 

That Hall sensor comes out of sleep mode 0.1% of the time. It wakes up for 75μs and then goes back into low power mode for 75ms.
Average current drain is 5μA.

Again, your maximum current draining component will be the pull-up resistor, same as when using a reed switch.

If your supply voltage is 5V

1MΩ resistor will draw 5μA
100kΩ will draw 50μA
50kΩ will draw 100μA

 

That Hall sensor comes out of sleep mode 0.1% of the time. It wakes up for 75μs and then goes back into low power mode for 75ms.
Average current drain is 5μA.

Again, your maximum current draining component will be the pull-up resistor, same as when using a reed switch.

If your supply voltage is 5V

1MΩ resistor will draw 5μA
100kΩ will draw 50μA
50kΩ will draw 100μA

@MrChips: Will it work with a 1M pull-up, whats the cons? The pros being longer battery life...

1400mAh = 1 400 000 uAh
1 400 000/100 = 14 000h => 583 days => 1.6 years for 50kohm

Is that right? Why NOT use a 1M? Will it affect the sensitivity of the hall switch?

 

@cmartinez DO you think my calculations are correct? 'cause then I'm using the 50k, it IS the recommended value on the datasheet...

 

Having to replace alkaline batteries once a year is not unreasonable.

 

the 1400mAh is rechargeable, so recharging once a year is definitely not unreasonable, dunno what the mAh is on non rechargeable AA's?

 

I can get 2600mAh normal alkaline AA's might go with them... but my rechargeables would work fine

 

@MrChips @cmartinez THE question: should the black line be there or not? ie Should I connect ground of the buzzer board's live/grounded wires to the ground of the hall switch's psu (3x 1400mAh NiMh batteries) My guess is I should, guidance will be appreciated, and remembering the previous advice, I should swop C_0.1uF with B_3.6V so its closer to the SIP3 hall switch?

 

ofcourse I can put the 0.1uF next to the UH8104 like this



@MrChips: have I learned anything yet? The 0.1uF is next to the SIP3, didn't see it at first but now it looks obvious ;-)

 

@MrChips the board you designed doesn't work anymore, not even shorting the signal cable or shorting on the jumper cable side does nothing, My hall effect switch produces 4.5V high, might that have damaged something? Oh and I tested the buzzer by manually inducing 9v into the wires, and that checks out, it works. Might I borrow some of your genius please?