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241  Using Arduino / General Electronics / Re: Homebrew PCB - Puzzle - Laminator Running Backwards After Jam on: March 25, 2013, 03:47:38 pm
Well, I just took it apart and set a screwdriver under the main cog. As I started teh motor I levered it in the opposite direction and it started going forwards again. Turning off and on and it goes right way, so the problem is solved.

I still don't understand how it continues in the direction it last went. I thought any start method would bias the field in a particular direction, CW or CCW.

Every day is a school day.
242  Using Arduino / General Electronics / Re: Homebrew PCB - Puzzle - Laminator Running Backwards After Jam on: March 25, 2013, 03:40:13 pm
The strange thing, Mark, is that it now permanently runs in reverse. If you switch it off and start again it runs backwards. I totally get where you're coming from about forcing a start in a certain direction, but AFAIK a shaded pole start can't be reversed without physically rotating the armature 180 degrees.

I've worked with larger capacitor start machines int he past and built in reversing on oil pumps by using a DPDT relay to swap the capacitor connections, but nothing changed on this at all. It just jammed and started going the other way.

Very odd.
243  Using Arduino / General Electronics / Re: A question about Arduino VIN on: March 25, 2013, 03:36:34 pm
Vin is just the raw voltage applied, before it is regulated down to 5v and 3v3.

So, if you used a power adapter pf 9v into the DC Jack then you'd have that 9v appear at teh Vin pin.

You could also take your 9v directly to that pin, instead of using a barrel jack.
244  Using Arduino / General Electronics / Re: What's in your parts kit? on: March 25, 2013, 03:33:54 pm
Cheap and fun stuff:-

LCD Display (16x2, 16x4 or 120x4) (16x2 can be bought for about $2.50-$3.00)
74HC595 8 Bit Shift Registers (pennies/cents)
PCF8574 8 Bit I2C Expander (about $2 in singles, down to $0.65 each in larger quantities))
Matrix Keypad (membrane or phone style) (
nRF24L01+ 2.4Ghz Radio Modules (a couple would be about $5)
Bluetooth Module (about $8)
SD Card Module (about $2)
A couple of 328P-PU (about $5 each) - so he can breadboard/pcb his own Arduino for learning

Apologies if I've repeated anything others have already suggested.
245  Using Arduino / General Electronics / [SOLVED] Homebrew PCB - Puzzle - Laminator Running Backwards After Jam on: March 25, 2013, 07:24:10 am
I wasn't sure where else to put this and it is PCB making related...

I use a laminator for toner transfer and the process works well for prototyping or small quantity requirements.

Usually my copperclad goes through just fine but yesterday I had a jam. I pushed the board through in the same direction it was moving but then it reversed and came back out! Now the laminator rollers are running in reverse direction, from rear to front.

I've taken it apart and thought I'd find some kind of jumped cog somewhere but I can't see anything amiss.

Everything is 240V AC with a single phase motor driving the rollers. It looks like a couple of LEDs are driven just with diodes, for half wave rectification, and large value resistors.

I can't provide any imaged until back home but just wondered if anyone had ever come across anything similar?
246  Using Arduino / Audio / Re: PCM Sound Output for my Atmega2560 on: March 23, 2013, 09:43:54 pm
The library probably uses a specific timer for the output, so check which timers work on which pins.

I had the same issue with the SimpleSDAudio library when moving from the 328P to 1284P. Sound output is on different pins due to the timer differences between the chips. It works fine though when the correct pins are used for the output.
247  Using Arduino / General Electronics / Re: Can I share the SCK pin (13)? on: March 23, 2013, 08:46:36 pm
They should both be SPI devices and actually sharing SCK, MOSI and MISO. Each should be on a separate Slave Select pin. This is usually labelled CSN on the nRF (Chip Select Not, as it's Active Low). The nRF also needs another pin for CE. This controls whether teh nRF is in Transmit or Receive mode.

The libraries being used should take care of asserting/de-asserting the respective SS pins, but it's not guaranteed. If in doubt then manually set their SS pins before and after using each device, to be safe. Only one device should be active at a time and then that will be the one to respond to any SPI data sent by the Master (the Arduino).
248  Using Arduino / General Electronics / Re: What is best - or smallest sized wire I can use for LEDs on: March 23, 2013, 08:42:42 pm
22AWG shouldn't present any issues in short runs for 1-3 standard 20mA LEDs in parallel.
249  Community / Products and Services / Re: Cheap Fusion PCB Service(Color Free) !! on: March 23, 2013, 04:45:11 am
Just received another order back, bang on 15 days again.

This one was 100mm x 100mm panels with 8 up 48mm x 28mm PCBs panelised.

They tested each individual PCB and marked two on one panel + one on another panel as bad. That's three PCBs out of 80. They actually sent me those panels (with 13 good PCBs) PLUS the full 10 perfect panels, so I've ended up with 93 PCBs instead of 80.

Another order of 5 up tiny PCBs on 50mm x 50mm also arrived with a friend.

These guys are still impressing me. It's not very often nowadays you can be absolutely happy with a service so it's a refreshing change. :-)
250  Using Arduino / General Electronics / Re: Electric Circuit - Power Supply Issue on: March 23, 2013, 03:44:10 am
It sound like you have some short when your fan is switched off.

My guess is that your 9v battery is a PP3, in which case the reason you're not seeing the same overheating/melting issues with the 9v is nothing to do with the voltage but actually the batteries inability to supply high current.

I also suggest all grounds get commoned as you could also have a path back through other components. Strange things can happen when you forget to reconnect all your grounds together.

Without a drawing of what you actually have then your not going to get any further wit help.
251  Using Arduino / General Electronics / Re: Multiple parallel secondaries for higher current on: March 20, 2013, 06:21:05 am
1) Is it a single phase transformer?
2) DO you have 4 wires coming out of the transformer?
3) What colour are your wires?

In theory yes, you can, but you need to be very careful about what you are doing.

If you have 4 wires then colour coding may give you a clue.

What you need to do is find the correct polarity for those two windings as you want to connect them in phase and not out of phase. Connecting out of phase will be like applying two power supplies shorted together and you DO NOT want to do that.

I would advise you DO NOT continue unless you are a qualified electrician AND totally understand the safety precautions, hazards and risks associated.

If I was going to do this then I would look for wiring to indicate polarity of the windings.

I would then join two wires of the secondary together.

I would ONLY connect TWO wires, to leave me three ends, which I would ensure are all separated and safe for energising.

I WOULD NOT connect the other two wires yet.

I would then power up the primary and test the ouput of the secondary. I would be looking for stated voltage between each single wire and the connected two. Across the outer single wires I would be expecting to get double the voltage or zero, with zero being what I want.

IF I had double voltage then the secondaries are in series and I'd de-energise and alter my commoned connection.

IF I had zero between the OUTER wires then I'd go ahead and connect the remaining two wires to put the secondaries in Parallel as required.

252  Using Arduino / General Electronics / Re: LEDs, Resistors, and wiring question... on: March 20, 2013, 04:21:55 am
You don't need to run the LEDs at maximum current. Even dropping to 0.5 or 0.25 times will result in a very similar brightness level as the human eyes response to intensity is logarithmic.

It wouldd be advisable to learn how to use a transistor to switch higher loads from an Arduino output pin as you'll need this sooner or later.

However, in this case, you could just wire your LEDs in parallel and run each at less than 10mA to stay within the limits of the pin output. Running at 5mA each would be best, to give a maximum 20mA on the Arduino pin.
253  Using Arduino / Programming Questions / Re: Random switch case with delay on: March 20, 2013, 04:12:47 am
Set a variable as a timer record
Set timer to current millis()
Generate a random integer between 1 and the number of patterns
Do your Case statement to determine Which pattern to use
On each loop() check if the difference between current millis() and your timer is more than 10s
If greater than 10s then reset timer record and generate a new random number
254  Using Arduino / Programming Questions / Re: My program is great ? on: March 20, 2013, 04:07:44 am
Pointless, non-conforming, post of the week???
255  Using Arduino / Programming Questions / Re: Another ATMEGA328-PU Bootloader Problem on: March 20, 2013, 04:06:04 am
The non-P 328 has a different Signature to the P version.

This isn't present by default in boards.txt or averdude.conf.

You need to modify both files to add support for the non-P 328, in order to burn a bootloader and set fuses. Once you have a bootloader installed the you have to revert back to the standard 328P board in IDE to upload sketches over serial.

I believe that Nicks programmer sketch might support the non-P and save you needing to make the modifications. I haven't tried it personally but I think I saw in the code that it looked like it supported non-P 328.

I've successfully burnt bootloaders to non-P using Arduino ISP with the mods to boards.txt and averdude.conf
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