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1  Using Arduino / Project Guidance / Re: Key fob jammer for my Volkswagen car on: Today at 08:45:49 am
Hi, can you talk to your car dealer, see if it is possible to disable the RF system with a switch inside the car.

So at night you turn off the rf system, lock the car with the key.

In the morning unlock the car with the key then turn on RF system.

Tom...... smiley

Simple, pressure the dealer to pressure the manufacturer to fix a security problem that they have in THEIR system.

2  Using Arduino / General Electronics / Re: Warm water on: Today at 08:28:52 am
Hi, you can now get, horror, instant cappuccino. Sacrilege.
A powder with all the ingedients.

Not like a real cappuccino...

Tom.....I wouldn't mind one now, but it sleepy bo's bo's time..... smiley
3  Using Arduino / Motors, Mechanics, and Power / Re: Design review: H-bridge on: Today at 06:52:09 am
Hi, why U8 and U10 drains connected together by a cap, then they don't go anywhere.
Same U9 and U11.

Tom..... smiley

Have you built this, does it work, i would protoboard this section by section, looks like a circuit proposal built from a datasheets.
4  Using Arduino / Motors, Mechanics, and Power / Re: DC motor positioning with external absolute encoder on: Today at 06:25:26 am
Hi,

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png or pdf?

Also what speed is your motor and does it have a gearbox?

Tom...... smiley
5  Using Arduino / Project Guidance / Re: how to set a frequency using a push button on: Today at 04:20:27 am
Hi, like setting a car cruise control.

Tom..... smiley
6  Using Arduino / Programming Questions / Re: Oscillating the direction of a motor based upon state of two switches on: September 30, 2014, 08:30:48 am
Hi,

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png or pdf?

Also are you using a motor, if so why do you have the servo library loaded.

Are you using a motor shield or a H-Bridge driver if you are using motors?

What exactly is your project not doing or doing wrong?

Tom...... smiley
7  Using Arduino / Project Guidance / Re: Measure signal produced by pH-transmitter on: September 30, 2014, 07:34:47 am
Hi, can you tell us the make and model of the transmitter.

Have you got it powered?
If not you may need to supply loop power of 24Vdc to get it to work, BUT before trying anything, GET the manual and check how it should be connected.

Have you tried measuring the voltage across the resistor with a DMM and the arduino disconnected?

Tom...... smiley
8  Using Arduino / General Electronics / Re: Avantages of proper bench power supply vs. alternatives? on: September 29, 2014, 05:38:00 am
Hi, look at this link.

http://www.practicalmachinist.com/vb/general/ot-hot-wire-foam-cutter-controlling-output-power-supply-question-277384/

Read about using constant current supply instead of constant voltage, it protects your wire and gives better heat regulation.

Tom...... smiley

PS, this site looks good for this topic.
9  Using Arduino / General Electronics / Re: Avantages of proper bench power supply vs. alternatives? on: September 29, 2014, 05:16:43 am
Hi, before you do anything.
What is the load, the wire cutter will consume energy, how much?

Current limit is essential, if you can get it, IT PROTECTS THINGS, even though some might think they are annoying.

Quote
And current limiting can be annoying on workbench power supplies,



Tom................... smiley
10  Using Arduino / General Electronics / Re: Breadboard voltages on: September 29, 2014, 04:26:20 am
Hi, I wouldn't go over 24V.
100V or higher would be dangerous for the op and the connections are not permanent or locked in.
If a live  wire popped out, not good.

Tom.... smiley
11  Using Arduino / Project Guidance / Re: Is it possible to make a color sensor out of an RGB led and phototransistor? on: September 29, 2014, 03:13:44 am
Hi, you would have to check the spectral response of the phototransistor.
This is to see if it is sensitive enough to the range of colours you want to detect.
Also the spectral output of the RGB LED to see if its output levels are equal or adequate.


If not you may have to do a calibration run to match and compensate for the differences, the same goes for the LDR.


Tom.... smiley
12  Using Arduino / General Electronics / Re: 3 phase SSR vs single SSR for controlling 240v appliances on: September 27, 2014, 03:33:01 am
Hi, if your hot water heater a decent one, there should be a circuit or connection diagram on it somewhere.
Even on the inspection cover.
If not google the make and model and see what you are working with.

If you cannot see how the thermostat works then I would leave it alone until I knew what I was working with.

Sorry but advising about this unit without knowing its layout is courting disaster.

Tom...... smiley
13  Using Arduino / General Electronics / Re: Darlington Array with Bipolar Stepper Motor on: September 27, 2014, 03:14:06 am
Hi,

http://www.nmbtc.com/pdf/motors/PM42S-048-HHC8.pdf

is your motor, the prefix is the manufacturer.

Tom...... smiley
14  Using Arduino / General Electronics / Re: Problems with various power supplies / ground loops? on: September 27, 2014, 03:08:37 am
Hi, we need a proper full circuit diagram, you must have one to get this far, if not then STOP and draw one.
A a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png or pdf?
The block diagram you have posted tells us nothing about your project is connected.

I agree with Boardburner2, check the voltages around the 7805 and if it is getting to warm, it sounds like current limit due to thermal shutdown.

Tom....... smiley
15  Using Arduino / General Electronics / Re: current leak from an input pin on: September 27, 2014, 02:54:20 am
Hi, what application do  you have that needs to consider the current going to an input that is in the uA range.?


Tom...... smiley
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