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1  General Category / General Discussion / Re: Electronics Stores in Austin - Seguin Texas? on: April 25, 2013, 03:55:13 pm
Thanks for the info and offer. I don"t think I'll go up to Round Rock this time. I'll only have a couple of hours in Austin before the flight, but maybe next time.
2  General Category / General Discussion / Electronics Stores in Austin - Seguin Texas? on: April 23, 2013, 08:39:25 pm
I'm not sure where to post this. I will be in Seguin TX (flying to Austin) for a few days and with all the high tech in the Austin area, I'm wondering if there are any cool electronics / hacker / maker stores in the area. Please share your secret sources if you have any.

I tried a web search and didn't find much that looks promising, other than Fry's, Radio Shack, Best Buy etc. Nothing against Fry's & the Shack, but we've got those here. I'm hoping there's a funky old Ham radio store or something like  American Science & Surplus ( in the area.

Steve from Illinois
3  General Category / General Discussion / Re: Arduino Due (released Oct 22, 2012) Compatibility on: October 01, 2012, 03:33:56 pm
I think it's a safe bet all of the "Arduino" commands ( will be supported; they will just run a lot faster. However, just as with the existing boards, Arduino functionality can be enhanced or improved by using low level programming and direct register read/write.
4  Using Arduino / Project Guidance / Re: Max7456 on: October 01, 2012, 03:26:33 pm
I'm not sure what you are asking for...

Are you having a problem with the MAX7456?

Are you looking for help to connect an Arduino to the MAX7456?

Are you looking for help writing code to communicate with the MAX7456?

If you really have no programming experience, then I suggest going through some tutorials on programming and Arduino first. You will need to control pins and communicate over SPI. You will probably want to communicate over serial because you can't see what's going on when the code is running in and Arduino, so it is helpful to put print statements in the code at various points and watch using the serial monitor, so you can track the logic of the code and see internal variables.

5  Using Arduino / Project Guidance / Re: Arduino to control existing PWM board? on: September 20, 2012, 05:25:20 pm
Yes, that is correct. There are cases where it might not be true, but that is very rare.

And please ask noob questions here before blowing anything up smiley trust me on that!
6  Using Arduino / Project Guidance / Re: wireless connection to a pc and smart phone on: September 20, 2012, 05:20:47 pm
Bluetooth from the phone won't go that far. A Class 1 Bluetooth dongle on the PC will (probably). You could make a bluetooth "repeater" that is located near the phone which then sends/receives data over a higher power network.

The higher power radio network could be the Open RF, Zigbee or any of a number of NRF24... transceivers..

WiFi may work, but when I asked about a non-internet connected WiFi network I didn't get any help. I'm quite certain it could be done with a PC / router, but I can't find an example of doing it with Arduino (or other small controller) and a WiFi shield. If anyone knows how to do it please let me know, either here or in my thread (,122566.msg921870.html#msg921870 to avoid hijacking this.
7  Using Arduino / Project Guidance / Re: Hot water line flusher on: September 20, 2012, 04:55:40 pm
I don't see how a recirculation pump is less environmentally friendly than dumping water down the drain.

Put insulation on your hot water pipes. It makes a big difference.

Recirc pumps are typically low power. They can be on a timer. There can be a trigger, so when you want hot water you push a button and it will start running. Of course it still need a minute or so, but push the button when you go in and when you're ready to wash your hands it will be there.

I don't see anything technically wrong with your proposal. Just make sure there are no leaks, the valve is normally closed and there is kill switch.
8  Using Arduino / Project Guidance / Re: Arduino to control existing PWM board? on: September 20, 2012, 04:35:25 pm
The ground of the motor controller and the ground of the Arduino should be connected together.
9  Using Arduino / Project Guidance / Re: Bluetooth-Android weather sensor on: September 20, 2012, 04:32:23 pm
I see, that is difficult. If I understand you can type the data in to the app or you can get this plug-in that works with the Kestrel. I only see three possibilities to automate it.

1. Write your own plugin. Somebody wrote the Kestrel plugin. Can they write (or give you enough info to write) a generic plugin that will work with an Arduino?

2. Make the Arduino look like a bluetooth keyboard to enter the data in text.

3. Hack / Crack the Kestrel interface and make the Arduino interface the same. Unfortunately this requires having a Kestrel and some bluetooth tools. Maybe someone will crack it.
10  Using Arduino / Project Guidance / Re: Uno, signal conditioning and an optical sensor on: September 20, 2012, 02:12:45 pm
QA probably means the pin. Often in electronics outputs are labeled 'Qx' (Qa, Qb, Qc etc.)
11  Using Arduino / Project Guidance / Re: Bluetooth-Android weather sensor on: September 20, 2012, 02:11:04 pm
It MIGHT be possible to simulate a bluetooth keyboard (see also HID - human interface device), so the Arduino reads the sensor values and the "types" the data on a keyboard.

As Pylon said, I doubt you will be able to get into the source code for the commercial app. Does it have the ability to interface to real sensors? If so you might be able to use the Arduino to simulate the regular inputs.

You can write your own app, which takes the data from the Arduino and performs the same calculations or use a lookup table to get the desired results. I am just starting down the path to writing Android apps, so I can't give any good advice, but here are a couple of tutorials I am looking to for guidance.
12  Using Arduino / Project Guidance / Re: Uno, signal conditioning and an optical sensor on: September 20, 2012, 01:56:48 pm
V = I * R it's not just a good idea, it the law. Ohm's Law.

You don't even need a divider. A 200 ohm resistor to ground will convert the current to a voltage from 0.03 to 3.2V.
13  Using Arduino / Project Guidance / Re: Arduino to control existing PWM board? on: September 20, 2012, 01:51:05 pm
Yes, a 10K digital pot should be able to replace the manual pot. That would be the easiest solution.

A relay can replace the on-off switch, but I would keep an emergency override switch in case the Arduino starts doing something you didn't intend. Always have a kill switch in automated equipment.
14  Using Arduino / Project Guidance / Re: How much can the Arduino cope with? on: September 20, 2012, 01:46:10 pm
6000 rev / min = 100 rev / second

100 revs / sec * 10 pulses / rev = 1000 pulses / second or 1mS between pulses.

You can't do it with millis() because at 4000-6000 RPM it will always read 0 or 1 millisecond since the last pulse time. micros() will work better. Alternatively you can measure the time for 100 pulses or count the number of pulses in 100mS (for example).

1 mS is enough time to read the state of three pins and check the time, but it depends on what you are doing with the information and how long it takes to process it. If the application can monitor speed for a period of time, and then do something with it (while not monitoring speed) then it should not be a problem. If you have to monitor speed continuously, then it depends on what else the system is doing.
15  Using Arduino / Project Guidance / Re: Radio Feasible method of communication for this? on: September 17, 2012, 09:48:10 am
A GSM shield can send a text message to your phone. You will need a SIM card / mobile account; last time I looked pre-paid cards were less than $50. You can send a lot of text messages before you need to re-fill the card.

The IOIO with a Class 1 bluetooth dongle MIGHT be able to get that far, but it will mostly depend on your phone's transmission power and antenna.

You can use a Zigbee or one of the many other RF links to a "repeater" near the phone which connects via bluetooth.

I am looking for a simple way to use the WiFi in my phone, but have been unsuccessful so far. If you find something, please post it.
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