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46  Using Arduino / Microcontrollers / good source for ribbon cables w/connectors? on: December 23, 2012, 11:06:30 pm
Anyone know a good source for ribbon cable type connectors?
I'm looking for a 16 pin single row, as well as a few others that I can find on ebay, but id rather get something sooner than 4-5 weeks
47  Using Arduino / General Electronics / sound like a burnt chip? on: December 23, 2012, 09:47:56 pm
I hand soldered a 328tqfp and I'm afraid I have burnt it, I took a while to solder it, the first attempt with hot air it didn't line up so I jad to heat the whole chip to move it, it was working for a day and now only works when I apply pressure to the chip, I metered out all the pins and they all have continuity, it just gets me because it works for a while, I left and came back to do some more programming and now this, id just swap it out but I wonder if anything else could cause this? I have proper decoupling ( 0805 .1uf cap under the ic) as well as a 10uf electrolytic <1in away so I don't think its that
Unfortunetly the only output I can see without my oscope is the lcd, but if I press reset and wait a sec then press down on the ic its not one sec into the program
It won't program unless I press down either : /
48  Using Arduino / Programming Questions / Re: calculating error, quickest way on: December 23, 2012, 09:10:24 pm
To keep it simple for now what I'm gonna try and do is that for when the frequency is <2700 scroll by frequency since there will be no error, >2700 start scrolling by OCR1A then update the frequency so it appears the frequency is being scrolled thru yet its still accurate although jumping around
49  Using Arduino / General Electronics / Re: Variable Voltage Regulator on: December 23, 2012, 08:31:38 pm
You can use pwm , a npn transistor and a low pass filter to directly get0-10v
50  Using Arduino / Programming Questions / Re: calculating error, quickest way on: December 23, 2012, 02:31:02 pm
Now that is an interesting idea, also would allow me to get those higher frequencies with a litle more accuracy
51  Using Arduino / General Electronics / Re: Automatic Switching to Battery on Power Failure on: December 23, 2012, 02:28:23 pm
Oh wow missed that, thought it was 12v battery,
52  Using Arduino / General Electronics / Re: Automatic Switching to Battery on Power Failure on: December 23, 2012, 10:23:05 am
Charging sla's aren't that bad, they are pretty robust(I toture them often with electrically abusive experiments), probably the most effecient way would be a mosfet, a regular diode would only be worth it at low currents, a germanium diode is better but still has current limitations(as well as heat)
Basically for that size battery you will want to charge it @.3-1amp constant current untill it reaches close to 13.8, then you have it constant voltage @13.8
Easiest way is to use a lm317 although @1amp you will need a heatsink
53  Using Arduino / Programming Questions / Re: calculating error, quickest way on: December 23, 2012, 02:36:56 am
How much did that board cost? Lol I already spent 70$ on this, and I'm finally just in the final proggramming phase working on the gui,
but unless someone can figure out that formula perhaps after a certain frequency I will just have it directly change the OCR1A number and display the frequency
54  Using Arduino / Programming Questions / Re: calculating error, quickest way on: December 22, 2012, 11:10:25 pm
Yeah I wish I thought of tnat before I finished the pcb, also my budget is kinda small but anyway, how could I apply dithering ? I can't find a decent source of the actual process and how to apply it to my thing
55  Using Arduino / Programming Questions / Re: calculating error, quickest way on: December 22, 2012, 06:40:12 pm
That's an interesting idea however it will not match the actual output because the error appears to change logarithmically(as in a graph of error vs frequency) tho I'm sure there is a linear equation because I believe when I graphed the difference between errors its linear, I just can't figure it out
56  Using Arduino / Project Guidance / Re: Interfacing TDS/EC Tester/Meter on: December 22, 2012, 06:34:36 pm
Even if you found which traces the output was on, how would you get that info? And the actual number is in the processor, the only info outside it is the i/o to the lcd
57  Using Arduino / Programming Questions / Re: calculating error, quickest way on: December 22, 2012, 01:43:51 pm
Well the problem is its not typed in but in/decremented with a rotary encoder, so for lower frequencies it just goes one at a time, at higher it would need to in/decre,ent by larger values, problem is that value changes, that's why I'm looking for a formula basically that mimics the curve of the error, I'm sure its simple I'm just not too well versed in math lol
58  Using Arduino / Programming Questions / Re: calculating error, quickest way on: December 22, 2012, 11:15:16 am
I know lol, but my gui doesn't know that, I would like it to automatically know
Like where normally I change by one instead I change to the next valid number
59  Using Arduino / Programming Questions / Re: How do I get the 3d byte of a word? on: December 22, 2012, 01:00:22 am
Add
Unsigned long 3dbyte =
Before that and youl be fine
60  Using Arduino / Programming Questions / Re: calculating error, quickest way on: December 22, 2012, 12:57:56 am
I'm using this to change the OCR1A value to get the desired freq
OCR1A = (8000000/freq)-1
So say I want 247khz the ocra would be 31 and the actual freq is 258064, so quite an errror, I could just jump by ocra values at a certain point where the error gets large but idk if there's an easier way
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