Good afternoon.  Got my Arduino up and running last night.  Didn't have any components to toy with so I wrote a variety of LED blinking test runs (random numbers to generate blinking speed etc etc).

It seemed all of them turned out to be around 4000 bytes which was half of the 8k chip that came with the Arduino.

No matter what I did to try to slim down the code it always came out to that size.  Is the compiler doing work for me to keep the file size down and leaves out comments and such so you can maximize the chip?

All of a sudden the 8k doesn't seem like a lot (well, it isn't ) when the basic LED test app takes up half the chip.

I really need to dig in and play around more but so far I love it and can't wait to try messing around with the many projects floating around in my head.

Take care!

This is quite the old project: http://www.tlb.org/scooter.html

But this guy built his own Segway clone using a few big motors, some batteries, a gyro and some C code.

I was wondering if this could be done with the Arduino with some cheap components and sensors?  

I don't have a Arduino yet (coming soon!) but I wouldn't mind trying to produce a very simple version of this.  Even if I could just find the cheapest gyro out there and see if I can appropriately read values from it and try to drive a small motor based on data from the gyro.

Looking forward to getting my Arduino kit, I've got a million ideas in my head; just a matter of implementing them!

Take care!

Problem solved.

It turned out that the relay needed more power to trigger than the Arduino could provide...  Also, my transistor needed to be adjusted for more power (I had some on hand).

So I replaced the load on the relay with a 9V battery and swapper out the transistor and it's working like a charm.

After getting a better understanding of relays after much Googling I have connected the relay in such a way so the "normally closed" works, I can create a circuit with the 12V DC power supply and the pump and it works.  So I re-created the circuit using "normally open"  (I now know how the common pin works).

However, I still can't get the transistor switch to send off enough juice to cause the relay to activate and closing the circuit so the pump gets turned on.

Could it be the resistor I'm using?

Twice while testing the circuit with the transistor (I didn't have a resistor in place) the USB port on my Mac shut itself off because it was drawing too much power.

Any thoughts?

I've been looking at it too long tonight so I'll continue tomorrow with the transistor problem and see what I end up with...

Would still appreciate any thoughts if anything can see where I'm going wrong here...

Thanks!

Good evening,

I know there have been a few threads on this board in regards to using a relay but I've been scratching my head and trying to get this circuit working for a while and I've given up....

What I'm working with:
- Arduino
- 12v1A pump
- 12v1A  SPDT relay (side 1 has the image of the coil on the diagram)
Here's an image:
- A NPN switching transistor

It's very simple, turning digital pin 2 on will turn the pump on.  

So I need help making sure my connections are right and I don't fry my board...

I'll do my best to express how I think the circuit should be, any corrections would be appreciated!

Arduino Pin 2 --> 1k resistor --> transistor base
Arduino ground --> transistor emitter
Transistor collector --> relay (side 1)
Arduino ground --> relay (side 1)

12v DC power supply + --> relay (side 2)
Pump power + --> relay (side 2)

12v DC power supply ground --> Pump ground


I guess I'm not sure where to connect the "common" 5th pin on the relay.

Obviously it's incorrect and I don't think I'm understanding the relay correctly.  I understand a small current across the coils will close the connection on the other side to create a separate circuit for the 12V DC power supply going to the pump but it's just not working out as planned.

Is it possible to trigger the relay directly from the Arduino without the transistor?

Thanks for any replies!  It's very much appreciated.  This is for an Arduino demo I'm doing next week so I'm hoping to have this circuit figured out by the weekend and running....

A transistor should do the job.  

You cannot "get" 12V off of the arduino, it is not a power supply and requires a power source to operate.  What will you be powering the arduino with?  You could attempt to power your pump with whatever you power your arduino with, make sure it has enough power for both.

Well the Arduino will be powered via USB since I'll be sending it commands over the serial port.

For the pumps I think I'll be using a 12V wall wort.

Only one pump will be operating at a time so I think I should be in good shape.  The pumps are shipping today I believe so I will hopefully get them shortly so I can begin playing around in time to get it polished up for the talk.

Good morning,

I'm going to be doing an Arduino presentation at the Orlando Ruby Users Group (demo'ing RAD http://rad.rubyforge.org) and I would like to do a simple BarMonkey project.

Using the first pump on the list here: http://www.sciplus.com/category.cfm/subsection/18/category/176

It's my understanding that using a transistor, I can use a digital out to control the transistor like a switch to turn power on/off from the pump.  I'll be writing some Ruby to send off commands to the Arduino over serial to tell it which pin and for how long.  This will result in a nice little drink dispensing system controlled by the Arduino.

Is my logic on controlling the pump with a transistor correct?  

Also, can I get 12VDC 1A off of the Arduino or will I need to power the pumps with another power source and drop a diode in my circuit so I don't end up messing up my Arduino.

Any suggestions or tweaks are very welcomed.

Thanks for any comments!

After seeing the analog gauge clock project on Makezine.com last week I got inspired and hit up my local surplus electronics shop and bought 4 really cool and very solid metal gauges made by Weston.  Each gauge is for a different measurement but they seem to be very solid and there's no reason why they shouldn't function correctly.

1 gauge measures between 0 and 1 amps; how would I easily control this?  I figure I'll be using the PWM pins like the other maker but what would be the best method to control that amperage?

The other gauges are for various measurements so I'll be doing a lot of experimenting to see how to appropriately get the pins on these gauges moving.

Any tips or suggestions would be greatly appreciated, once I get home I'll be getting the measurements that the gauges are meant to display and will do some further googling.

The goal is for a nice clock, I plan on mounting in a nice wooden enclosure.  

I like the RTC approach simply because it's less hassle.  If you don't want to drop $15, you can get the DS1307 in a DIP package for $4 from Digikey (of course, then you still need the battery, the crystal, etc).  You don't even have to convert the values from the RTC -- they are BCD just like the 74141 expects, but you do have to mask off the AM/PM bits, clock enable, etc.

My project is going to use four large LED-based 7 segment displays, but the clock functionality is kind of a side thing.

I like the RTC approach as well since it is only $15 and it would then mean I have a very accurate clock that I can move and not worry about resetting the time.  Plus it will save me room for other logic (I might interface temperature and any other sensors I can find to generate information to display).

Plus this will most likely sit on my desk at work and I might put it away when I leave the office.  So plugging it in each morning and have it automatically set the time will be great.

Thanks for the code as well up top!  That will definitely come in handy.

I've thought about getting this to drive a Nixie tube clock that I plan on building and using the Arduino to control the tubes.

I liked the idea of the RTC, that way when I power the clock I will automatically have  the time.  Just wondering if it's worth the $15 or if I should just get some push buttons to increment the hour/minutes and set it every time.

I do think though using the RTC breakout board from Sparkfun would save me a lot of code when I can just pull the values from the RTC, convert to binary and send off to the 74141 IC that is driving the Nixie.

Good morning,

I recently snagged the following touch screen from a surplus electronics shop.  With 5 wires I figured it shouldn't be too difficult to interface with an Arduino.  Does anyone have any insight to how I should be monitoring these wires to figure out how exactly the interface works and how I could determine X/Y cords to where it's being touched?

The surplus shop had literally dozens of these still wrapped in packing paper.  If they're able to be easily interfaced I might just snag them all and sell to other hobbyists on eBay or by some other means.

Details:
Microtouch R2.0
209A-93-A2293R
13-4261-00-01

Wire colors:
Orange, White, Green, Yellow, Black




Find higher res shots here...
http://www.flickr.com/photos/mdweezer/1287759205/
http://www.flickr.com/photos/mdweezer/1287757297/

Hello.

I'm looking to build a Nixie Clock with 4 tubes I've got.  They'll be mounted on top of my enclosure (it will be a wood top and base with acrylic on all sides.  On the front I would like to have an analog second hand which will rotate a full 360deg every 60 seconds.

Should I just buy a small clock kit and use that or would it be worth finding a small motor to interface with my Arduino to accomplish this task?

I was curious if I ripped a small motor that cell phones use to virbrate, just determining how I would control speed to make it accruate.

I have some intentions to build a Nixie Tube clock with the Arduino.  I'll be running 9V to a DC step up converter to get around 170V.  When all of that is interfaced and grounds are correct, will the Arduino have any difficulties with it?

I certainly don't want to fry my board and I'm definitely not a EE major; just bored and teaching myself some new tricks.

Thanks!

Browsing my local electronics shop (aisles and aisles of thousands of components and scrap from anything you could ever imagine!), I stumbled upon a box of Nixie tubes.  I've seen many project clocks using the tubes but was wondering if anyone has done anything with Arduino and a Nixie tube?

Looking around it appears they require a massive powersource.  I bought one ($3 each) to see if I could just mess with it but I haven't taken a dive into anything yet.  I miight scour google some more to find what exactly I need to do to power it and how to make the gorgeous digits glow.

There is a circuit diagram here http://www.arduino.cc/playground/uploads/Learning/solenoid_driver.pdf that should would work for driving your pump without a relay. The pump motor replaces solenoid L1 in that diagram. The suggested components including the TIP102 transistor should be fine for your app if the pump only draws 1 amp.


If you are more comfortable using a relay you can either select one that can operate on 5v at less than 40ma or use the circuit above but replace the pump with the

Excellent!  Thank you very much.  That diagram is perfect.

My only concern (not so much a concern but unfamiliarity) is with the power.  I need to determine how I'm going to get my 12V 1A power for the pumps.  I'm 80% I have a wallwort power supply I can use but if anyone has any suggestion for a smaller battery or something that would be fantastic.  

Would there be any alternatives to make this solution more portable?  Can you get 12v1A from a USB port if you step it up or would that not be worth the trouble?

Again, thanks for the schematic, that makes a lot of sense and I should easily be able to find the proper transistor (the only reason why I had a relay in the equation was so I could handle the 12V1A, I didn't want to overheat the transistor in case I didn't have an appropriate one).

Thanks again!