http://www.qprox.com/products/qt102.php I found that circuit then found more info on here about another circuit.. I can't figure out by reading the pdf exactly how to make it a simple on/off switch. Im not sure how to cancel out the count down completely..? Could anyone help me. or maybe draw a diagram for me? It's pretty simple Im sure, I just can not figure it out completely..
this has been covered a million times. http://forums.bit-tech.net/showthread.php?t=100148&highlight=qtouch
awesome thanks for pointing me. but i read over that thread it doesnt even cover this specific chip as far as I could see at all? or did I miss something you read? or maybe you missed what i wrote? EDIT: I just reread that topic again. And aside form one person posting a diagram of the qt113 in constant on mode, then having issue's with it. now one has covered anything on the chip i asked about. The control is for in my car. To control a multiple number of parts As I plan to have multiple switches like these. Also plan to use others such as a few momentary high's and a couple the can be used to hold a high for as long as my finger is in proximity.. but for now getting this circuit figured out is my primary objective.
sorry, didn't realize there were different models. to cancel the countdown, i think the data sheet is showing to just ground the time pin. i guess i'm not sure what your question is.
well that is it. but is it as simple as groundingt he timing pin. from what ir ead it is more then that. I jsut cant figure out what else is needed.
ya, that is pretty much the worst data sheet ever. if you don't need the time function on the chip, why not just use the qt100? edit: its pretty complicated. you have to ground the time pin. then you have to pulse the SNS pin thru resistor Rm. figure 3.8 and table 3.6 in the data sheet tell you how to do it. in the table, you want to reference the first row. i'd go with a different chip, as stated above.
This was something I was trying to figure out for a while too, I still have not implemented it yet (It is going to switch a 12v line to leds/cathodes). It should be as simple as using a QTxxx ic that has a high output e.g. the QT118H, wiring it so that it works in toggle mode like a flip-flop and hooking the output to the base of an NPN transistor. I was going to use a TIP132 Darlington mosfet for this. EDIT Just read your post in the other thread, the QT wouldn't directly be able to switch the relay, you'd have to implement the mosfet as above and have that switch the relay. What are you using it for? You might be able to forget about the relay and just use a mosfet.
TIP132 isn't a mosfet, it's a bipolar so would work fine on a 5V signal (with a suitable base resistor). Though its 12A rating is gross overkill for the relay application, with most relays any little bipolar with gain over 100 would be OK with base resistor 2.2k minimum. The way I read it, the basic active-high on/off switch circuit would be Shout up if you spot an error. R1 & C1 are estimates, may need adjusting depending on the sensor, etc. With the TIP120/121/122 power darlingtons as Q1 you don't need R3, there's a suitable resistor chain to ground in the package.
i'm assuming you're talking about the qt102 for that IC. And i think with R2 (Rm on the datasheet) tied to ground like that, it would just do an auto-turn off every 15 minutes, unless i'm reading section 3.5 of the data sheet wrong. i gotta go right now, so i'll take a better look later.
i think i have it figured out. just need to transer it off paper to on here. Which I hope to do soon. hopefully be able to get it up tomorrow.
here is what i came up with this is active hi. Now if you took the from "out" pin 1, and and ran it plus its resistor to VDD instead of VSS you would get active low. This set up allows me to touch the sensor and activate the trigger. then touch again after 2000hrs if i want, and tunr it back off. not i need to find a relay i can run off this to control higher amp 12vdc lines.. the LED I have in the Sense pad is backwards i think i dont remember. But It is ther ebecause it will be behind the sense pad so when I activate the device a light comes on to tell me. thoughts? Now I need to figure out all the values I need for my resistos etc..
I'm struggling to reconcile Fig 2.1 (active high output, 15 minute auto switch-off) with Table 3.2. The figure shows pin#6 (Vt) to ground (Vss), which the table says gives infinite delay to switch off, so I see a contradiction by Quantum. I based my circuit for "active-high, no auto switch-off" on the tables 3.1, 3.2 and 3.4, but it's turned out identical to the "active high output, 15 minute auto switch-off" Fig 2.1 example. The E102 Evaluation board link setting tables seem to agree with the datasheet tables and my circuit. Rm (my R2) tied to ground gives a x1 multiplier to the delay, and better sensitivity than the x24 setting. It doesn't affect the 'infinite' setting but would turn a 15-minute delay to 6 hours if R2 were tied to +5V (Vdd). 'Suck it & see' seems to be the best approach.
