Show Posts
Pages: [1] 2 3
1  Topics / Home Automation and Networked Objects / Re: Sparrow - a 2.4GHz prototyping node for a mesh network on: June 23, 2013, 03:58:46 pm
Im really interested, Let me know how I can help .
2  Topics / Home Automation and Networked Objects / Help choosing the right wireless module on: June 23, 2013, 03:19:55 pm
Hi All,

I'm very basic at electronics and wireless.

What I'm trying to do is , get my battery/solar PV voltages and current monitored remotely from another location on my home.

I've chosen the Raspberry Pi to store/make the data available all over the home/internet with Ethernet connection.

NRF24L01+ module with printed antenna is used to communicate the Ardino and the Raspberry pi which acts as a hub.

I went with the NRF24 at first place because they are very cheap than lets say xbee , at just 2$ it was great and cheap to learn .

So far I've succeeded passing the data from Arduino back to raspberry Pi however it works only with small distance (4M-5M) passing 1 wall or so.
I need to be able to pass this data through almost 3-4 walls of concrete and with distance of roughly 10-12M or less.

There is 2 other vareity of the NRF24 circuits available. one with a only SMA antenna.. and another with PA/LNA and SMA
http://www.ebay.com/itm/NRF24L01-PA-LNA-SMA-Antenna-Wireless-Transceiver-communication-module-2-4G-1100m-/310673096920?pt=LH_DefaultDomain_0&hash=item48558f40d8

costs about 12$

http://www.ebay.com/itm/Arduino-2-4G-NRF24L01-Wireless-Transceiver-Module-SMA-Antenna-Microcontroll-/200932672566?pt=LH_DefaultDomain_0&hash=item2ec8854436
costs about 7$


I want to know if PA/LNA is worth the extra 5$ or would the SMA antenna alone do the job for my requirement?

Is bigger antenna version required at both the ends or would it suffice to have the HUB use the wireless chip with bigger antenna and leave the sensors with the basic  NRF24L01+ without external antenna?

Let me know if this chip will do the job , or if i should consider other alternatives like xbee or RF12M










3  Using Arduino / Microcontrollers / Re: DS1307 Heats up on the soldered board on: March 27, 2013, 12:35:05 pm
I thought the ATMEGA has internal pullups on the SDA/SCL i could be wrong? . like i said I dont even have the ATmega inserted on the setup and it would still over heat..

It does, and if the Wire library is being used, it will enable them. It will probably even work this way, but the pullups are technically too weak. External pullups between 2.2K and 4.7K would be best. But either way, this will not cause overheating.

Four posts in you tell us about the voltage regulator. Have you measured its output?



Jack,

I do use the Wire library lol.. A software engineer cannot talk the I2C's,etc himself haha..
Yeah output it fine.. 5V exact.

Now I tried to just use the output from voltage regulator to the DS1307 VCC and GND and nothing else.. it doesnt heat up.
Im trying everything from scratch .


Jack, please look at the schematic, then tell me THIS WILL do the job.. I would wire all the things carefully on a larger solder board and try.
4  Using Arduino / Microcontrollers / Re: DS1307 Heats up on the soldered board on: March 27, 2013, 11:56:32 am
You are missing pullup resistors on SDA, SCL, I don't that will cause overheating tho.  Unless the uC is driving the pins high as regular digital outputs and not I2C/Wire outputs.
Any chance the devices are just being installed 180 degrees around? That would certainly make them warm.

I thought the ATMEGA has internal pullups on the SDA/SCL i could be wrong? . like i said I dont even have the ATmega inserted on the setup and it would still over heat..

No i think they are not 180 deg
5  Using Arduino / Microcontrollers / Re: DS1307 Heats up on the soldered board on: March 27, 2013, 11:54:26 am
Make sure Vbat is connected correctly, the + side is the "back" of the cell.  Remove all ICs, check for shorts with the DMM and then apply power and verify voltages at the socket pins.  Check all pins to be sure power or ground isn't shorted to one unexpectedly.  You should have quit after two.  smiley-wink

Vbat is correctly connected the cell.. , I do not have any ICs apart from the Ds1307, checked shorts, etc allready for many hours lol.

Please check my schematic and let me know if everything looks OKAY there, I can wire all up from the start again and see if that would fix.
6  Using Arduino / Microcontrollers / Re: DS1307 Heats up on the soldered board on: March 27, 2013, 11:49:38 am
I feel like something is wrong on the soldered board do you need photos ? I gave schematic on the above post.

When i connect the breadboard version to the computer using USB / 5v rail from the UNO board, it doesnt over heat.

Over heating happens ONLY when we use a wall wart (+12v) connected to my own voltage regulator which uses 7805 with 470uF and a 100uF capacitors ( with 2 104 ceramic capacitors )

could this be due to the voltage regulator?

Also note my ds1307 dont seem to be frying because when i use the breadboard version they are working.. I ve used like 3 of them haha hopefuly they are not all dead yet.



7  Using Arduino / Microcontrollers / Re: DS1307 Heats up on the soldered board on: March 27, 2013, 11:32:21 am
Lowest I have is about 560 Ohms will that do?
8  Using Arduino / Microcontrollers / Re: DS1307 Heats up on the soldered board on: March 27, 2013, 11:10:23 am
I removed the ATMEGA from the dip socket and still it overheats. I have swapped many DS1307s and it happens on all of them.
9  Using Arduino / Microcontrollers / DS1307 Heats up on the soldered board on: March 27, 2013, 11:07:32 am
Hi All

I have a simple light timer based on the ATmega328..

It has a push button to set time(just hour ), a small LED  and a DS1307 for RTC.

The problem now that we have is the DS1307 does over heat soon after connecting the circuit to the 5v..


I have attached the schematic. I have triple checked for all shorts,etc.. im stuck.

The DS1307 heats quickly A LOT.
10  Using Arduino / General Electronics / Re: how to reduce the electrical noise on: March 22, 2013, 05:57:20 pm
OK I have measured the voltage across my 12v wallwart lol it goes UPTO 35V during flickering.

I tried to replace my nokia phone charger and see what happens, it keeps its voltage stable..

I think the problem is my cheap crappy wallwart.. everyone agrees?

11  Using Arduino / General Electronics / Re: how to reduce the electrical noise on: March 22, 2013, 05:49:58 pm
I use a 7805 with 2x 470uF decoupling capacitors .. and I see more than 5V during the light flickers ..

Input is 12v from the wallwart which already has its own regulators. should i replace wallwart and try?

or should i change the voltage regulator IC to be something better than this?

12  Using Arduino / General Electronics / Re: how to reduce the electrical noise on: March 22, 2013, 05:44:02 pm
Hi MarkT,

Thanks for the answer,

To keep everything out of equation I disconnected all my PIRs and kept the arduino to the minimum.

I measured the voltage across the +5 and GND.. while the Flourascent light is flickering.

I saw voltage spikes upto 6 or 7 sometimes even more during this and hence the AtMega is restarting.. Is that possible?

Will atmega reboot when this happens?

I use the same wallwart to power the ULN2003 for  8 relays as well as the ATmega . will this cause Ground loop?

13  Using Arduino / General Electronics / Re: how to reduce the electrical noise on: March 19, 2013, 04:18:49 pm
Hi  MarkT,

Staircases are CFL lights  and yeah they are totally independent of the florescent

There are 6 of them and I have wired all of them to relay board which has 8 relays and an ULN2003.

I have ensured the digital wires and AC mains wire are separated out by few inches.


14  Using Arduino / General Electronics / Re: how to reduce the electrical noise on: March 19, 2013, 03:16:03 pm
I don't usually build a circuit with PSU rail caps less than 100uF.  Often, 470uF.

Now If i replace my 2 10uF with lets say 470uF, u think that would improve/help this ?
15  Using Arduino / General Electronics / Re: how to reduce the electrical noise on: March 19, 2013, 02:10:22 pm
I think a pull–up resistor between a pin and VCC would help.


Which pin and VCC ? sorry im very new to arduino land.
Pages: [1] 2 3