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166  Using Arduino / Project Guidance / Re: NRF24L01 can not be initialized on: August 19, 2012, 09:05:50 am

When both were running I scanned with my phone for available Bluetooth Devices but nothing was found.

The nRF24L01 is not a bluetooth device.
167  Using Arduino / Project Guidance / Re: Searching for cheap complex wireless solution on: August 11, 2012, 05:55:38 am
RF24L01 modules are cheap. Take a look at this: But I think the library doesn't works with the attiny.
168  Using Arduino / Sensors / Re: DHT11 Sensor code issue on: July 15, 2012, 08:27:28 am
I just installed Arduino 1.0.1 and it didn't come with the DHT library. You can find it on the Arduino playground.
169  Using Arduino / Project Guidance / Re: Question about servo's and servo controllers. on: July 12, 2012, 03:58:08 pm
The Dagu quadbot uses only 2 DOF legs, so 8 servos in total. Absolutely no problem to control 8 servos with an Arduino Uno. Just make sure your battery is strong enough to power 8 servos.
170  Using Arduino / Motors, Mechanics, and Power / Re: TLE5206 5A Motordriver (Final Status) on: June 25, 2012, 02:22:21 pm
Do you really need the LM338T? Or are you using it because your power source has a to high voltage for the motor?
I need a 3A dc motor controller for an old RC car and was thinking about using the TLE5206.
171  Using Arduino / General Electronics / Re: Simplest/Slowest/Cheapest/(50meter range) to Interface to Arduino? on: June 22, 2012, 05:02:23 pm
I have a bunch of nRF24L01 modules, the small cheap ones don't have a range of 50 meters. More like 25-30 meters, with a clear line of sight. I have a couple of the more expensive (20$) version with amp and preamp. I've done some testing with those, it involved using my car... I can control my robot from 1,2km distance  smiley-twist
172  Using Arduino / Sensors / Re: NewPing (Ultrasonic) Library for HC-SR04, SRF05 and SRF06 sensors - v1.3 on: June 17, 2012, 09:50:46 am
Has anyone used this library in an obstacle avoiding robot sketch? I have a simple obstacle avoiding sketch that uses an old ultrasonic library, it works. But I wanted to try it with this library. Can I use "Distance = srf06.ping_cm();" in a sketch without the pingtimer/pingspeed code? Or do I have to use the "pingTimer" and "pingSpeed" like in the example? This makes it much harder to use in a sketch. I tried writing a function that returns the distance but I can't get it to work (I'm not much of a programmer).
173  Using Arduino / Project Guidance / Re: noob 1307 RTC issue help please on: June 16, 2012, 04:48:05 am
SDA and SCL on an Arduino Mega are on pin 20 and 21, they are not on the same pins as a Duemilanove or Uno.
174  Topics / Robotics / Re: Why can't hexapods walk faster? on: June 14, 2012, 03:39:27 pm
Buy the fastest servos and write efficient code. You need to find the most optimal "walking gait" for your hexapod depending on mechanical construction/servos. I'm quite sure the hexapod in the video can walk a lot faster then is shown in the video.
175  Using Arduino / Motors, Mechanics, and Power / Re: Newbie needs help with servo project on: June 14, 2012, 02:37:35 pm
Are you sure that you can position a winch servo like you can with a standard servo?
176  Using Arduino / General Electronics / Re: Is there any cheap component shop? on: June 07, 2012, 02:18:33 pm
I'm in Belgium and the big wholesalers like RS and Farnell only sell to companies over here. So I buy most of my stuff from Chinese Ebay sellers and Tayda electronics in Thailand. Cheap but you need to have some patience.
177  Using Arduino / General Electronics / Re: My first PCB design with ATmega328P-PU, will this work? on: June 07, 2012, 01:28:52 pm
Your comments are very welcome. I did not expect to get such a long and good explanation. I have a degree in electrical engineering and learned the basics of electronics in school 15 years ago. My career took a different path, I now work for an engineering company as a safety advisor.

Yesterday evening I soldered an LM2576 and the necessary components to a PCB and did some testing. I first attached a couple of leds, and measured almost exactly 5V powering it from my 25A lab power supply with only 7,2V. I then started attaching some 2W resistors till I got 2,5 amps out of the regulator. The voltage dropped a bit to 4,89V, which is still acceptable. So the cheap China inductor is up to the job smiley I did not expect anything else as I did a lot of googling before I bought them. I found several people that have used the same inductors from ebay with the LM2576 regulator. The LM2576 can be found very cheaply, I paid 0.58$ a piece.

As for the board: I've decided to ditch the ICSP header as I will never use it. I don't have a programmer to connect to it. I only need the ftdi header to upload sketches and use the serial monitor. I've already bootloaded a couple of ATmega328's on my breadboard, which was very easy.  I've also decided to leave out the led on pin 13 and the small inductor as it might cause more issues then do any good. I've added a ground plane to the top of the board and made most traces a lot wider, especially the VCC and AVCC connections. I've attached 100nF caps to both those pins. I'm going to leave all the big caps on the board. From experience I've seen that they are helpful when you power a lot of servos.
178  Using Arduino / General Electronics / Re: My first PCB design with ATmega328P-PU, will this work? on: June 05, 2012, 02:26:37 pm
Thanks for all the comments, much appreciated.

I've changed my design to a 2 layer PCB, was very easy in Eagle. Moved most of the traces to the top layer (red), so now the bottom (blue) is mostly ground. Made room for lots of caps, I'll do some testing with the board to see if it's necessary to put them all on. I have lots of electrolytic caps from decent brands, I'll will use the highest rated voltage ones that I have (35-50V) Those should be good enough. I only need to order the small 100µH inductor that's connected to the ATmega328P, all other parts I have. I'll have the board made by Seeedstudio (24.9$ + 8.1$ shipping for 10pcs).

179  Using Arduino / General Electronics / Re: My first PCB design with ATmega328P-PU, will this work? on: June 04, 2012, 02:25:05 pm
Going to a dual layer board might be a good idea. Just need to find out how to make vias in Eagle.
What kind of caps are low ESR and are available in 1000µF? I thought that only electrolytic caps are available in that size? I know these are high ESR and not the best suited for this application. I hope to power 12 small servos from the board for a quadpod (4 leg / 3 dof) or hexapod (6 leg / 2 dof).

This video shows 48 servos (I have the same servos) driven by a 3A 5V regulator, it's an LM2676 on an Mega1280 based board. I have the same board that I use in another robot.  I thought why not make my own... 
180  Using Arduino / General Electronics / Re: My first PCB design with ATmega328P-PU, will this work? on: June 04, 2012, 01:22:24 pm
Thanks for all the comments. The board is single sided, I'm planning to have it made at Seedstudio or Iteadstudio. I'm going to reposition the regulator and retrace connections. I just had another look at the datasheet and can see my mistake. I bought 10 inductors on Ebay rated at 5A 100µH so they should be strong enough. I'm aware that servos are noisy things that's the reason for the big caps, the regulator needs a 1000µF cap on the output according to the datasheet. I'll add a diode across R1. Designing this board has been a big learning experience. I've spent hours reading datasheets and watching Eagle tutorials on Youtube smiley
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