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by PLCGuy
Wed Nov 20, 2013 1:28 pm
Forum: Gaming
Topic: Possible to make a game that requires a lot of data
Replies: 11
Views: 1939

Re: Possible to make a game that requires a lot of data

As others have pointed out, a Pi could handle this. You're not talking about a lot of data, actually, by any modern definition at least as far as I can tell from your description. What I don't understand is: Unless this is specifically an electronics project, or unless you specifically want the TV b...
by PLCGuy
Sat Nov 09, 2013 9:25 pm
Forum: Networking and servers
Topic: Wifi dropping (using Edimax EW-7811UN)
Replies: 16
Views: 31668

Re: Wifi dropping (using Edimax EW-7811UN)

Firstly, let me say that I really don't know what I am talking about. ...but from your log, it looks to me simply like your wireless is dropping as was mine, and the OP's. I think the total lack of an antenna (on my adapter at least) makes it really vulnerable to noise and signal loss. What I think ...
by PLCGuy
Wed Oct 09, 2013 10:48 am
Forum: Python
Topic: Speedometer for my Electric Car Project
Replies: 2
Views: 1500

Re: Speedometer for my Electric Car Project

Just for the sake of completeness, I feel compelled to point out that GPS isn't how a car would typically measure speed. It won't work if you are indoors, or under a bridge, in a tunnel, etc...when the GPS signal fails. I also suspect this approach will be a little laggy. Ok, I actually think it wil...
by PLCGuy
Wed Oct 09, 2013 10:35 am
Forum: Networking and servers
Topic: Wifi dropping (using Edimax EW-7811UN)
Replies: 16
Views: 31668

Re: Wifi dropping (using Edimax EW-7811UN)

After a bit of fussing I have a setup a crontab with the following: Using sudo crontab -e : */5 * * * * /usr/local/bin/testwifi.sh 2> /var/log/testwifi.log Then the actual script called testwifi.sh echo '/usr/local/bin/testwifi.sh log' TESTIP=192.168.1.1 ping -c4 ${TESTIP} > /dev/null if [ $? != 0 ]...
by PLCGuy
Tue Oct 08, 2013 11:42 pm
Forum: Networking and servers
Topic: Wifi dropping (using Edimax EW-7811UN)
Replies: 16
Views: 31668

Re: Wifi dropping (using Edimax EW-7811UN)

Ok, found a previous thread that seems to cover it nicely here: http://www.raspberrypi.org/phpBB3/viewtopic.php?t=54001&p=413095 ...they suggest writing some python code to check and restart. I found another site where the author did it all with bash scripts and cron. I've opted to try the cron appr...
by PLCGuy
Tue Oct 08, 2013 10:10 pm
Forum: Networking and servers
Topic: Wifi dropping (using Edimax EW-7811UN)
Replies: 16
Views: 31668

Re: Wifi dropping (using Edimax EW-7811UN)

Full disclaimer: I don't know anything about what I am about to say, but I am trying to solve a similar problem. From my log file (Which looks similar to yours, except I don't use DHCP) it seems to me that the problem isn't so much the wireless going down, which sucks, it's that it won't ever come b...
by PLCGuy
Mon Oct 07, 2013 2:03 am
Forum: Beginners
Topic: Carnaval automation, replacing a plc
Replies: 2
Views: 759

Re: Carnaval automation, replacing a plc

My two cents, as someone with an awful lot of PLC experience, is you're better off learning the PLC basics if you already own the hardware and keep it in the PLC world. It's just easier to do, the PLC is purpose built for this type of task, includes features to make sure things work as expected (wat...
by PLCGuy
Sun Aug 25, 2013 12:01 am
Forum: Beginners
Topic: GPIO Thru Connector?
Replies: 1
Views: 432

GPIO Thru Connector?

Hi, I guess I want to have my cake and eat it to: I'd like to be able to stack an Adafruit LCD plate on my RPi, but also be able to run a ribbon cable out of it. I have already attached a regular height 26 pin connector to the LCD plate, so it's too late for me to make it possible for a cable to con...
by PLCGuy
Fri Aug 16, 2013 6:53 pm
Forum: Beginners
Topic: Critique Please: 1st RPi Circuit
Replies: 10
Views: 1870

Re: Critique Please: 1st RPi Circuit

Another way of switching your oven, would be to look into using A Opto isolator switching a Power Triac, ,( AC solid state switch ) This will give you total isolation between your Pi low voltage and Mains 120v Ac , Also no relay Contact bounce or spark noise I considered it. I decided against it fo...
by PLCGuy
Fri Aug 16, 2013 12:22 am
Forum: Beginners
Topic: Critique Please: 1st RPi Circuit
Replies: 10
Views: 1870

Re: Critique Please: 1st RPi Circuit

First stick to using a purpose built power adapter I am - I'm just going to be removing it from it's case and direct wiring a cable to it, rather than plugging it into the wall. I need both 120VAC and 5VDC inside my enclosure, so I don't want to run two power cables from the wall. Don't connect the...
by PLCGuy
Thu Aug 15, 2013 2:53 pm
Forum: Beginners
Topic: Critique Please: 1st RPi Circuit
Replies: 10
Views: 1870

Re: Critique Please: 1st RPi Circuit

The capacitor should go between 5V and 0V so it sits charged to supply voltage. The idea is that it will supply a little extra kick when the load is energised. Ah - I got it, when you said keep it close to the coil, I thought it was there to give that extra kick to the coil itself. I understand now...
by PLCGuy
Thu Aug 15, 2013 1:28 pm
Forum: Beginners
Topic: Critique Please: 1st RPi Circuit
Replies: 10
Views: 1870

Re: Critique Please: 1st RPi Circuit

Everyone thank you for your replies - I really appreciate it. Some specific responses, and a new schematic are attached... I am enamoured by your diligent use of the classic black-on white colour scheme. Your congruent main AC busbars are also appealing and de rigeur. Unfortunately, I don't feel I w...
by PLCGuy
Wed Aug 14, 2013 5:47 pm
Forum: Beginners
Topic: Critique Please: 1st RPi Circuit
Replies: 10
Views: 1870

Critique Please: 1st RPi Circuit

Hi - Before I blow up or burn down something, I'm hoping to get feedback on my first RPi circuit. This isn't built yet, I don't have the RPi yet (on its way!), so I could be completely wrong and not know it. I'm building a sous vide cooking controller. A common project I know, but this seemed like a...
by PLCGuy
Tue Aug 13, 2013 11:08 pm
Forum: Beginners
Topic: Extra Pullup for DS18B20? Why?
Replies: 5
Views: 1983

Re: Extra Pullup for DS18B20? Why?

...actually wait a minute, the ds18b20 talks the Dallas protocol, which I think is done bit-banged on GPIO 4 in the tutorial...?

So the 4.7k won't be in addition to the I2C pullup, it's doing the same work as the I2C pullup but on the 1-wire Dallas network, not the I2C network.

Do I have that right?
by PLCGuy
Tue Aug 13, 2013 4:18 pm
Forum: Beginners
Topic: Extra Pullup for DS18B20? Why?
Replies: 5
Views: 1983

Re: Extra Pullup for DS18B20? Why?

The 4k7 resistors are just acting as pullups in the tutorials. If you fit it, then it will be in parallel with the 1k8 resistor on the RasPi giving you an effective resistance of approx 1k3. ...but that's where it's confusing: The tutorials are specifically for connecting the DS18B20 to RPIs, and a...
by PLCGuy
Tue Aug 13, 2013 1:37 pm
Forum: Beginners
Topic: Extra Pullup for DS18B20? Why?
Replies: 5
Views: 1983

Extra Pullup for DS18B20? Why?

Hi, After some reading it's my understanding that the RPi has an existing 1.8k pullup resister internally for the I2C comms. I've purchased an RPI along with the adafruit LCD+Keypad kit (which is basically the GPIO expander). The tutorials show that I should be connecting the GPIO expander with no p...
by PLCGuy
Tue Aug 13, 2013 1:32 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C / Connecting while On?
Replies: 2
Views: 647

Re: I2C / Connecting while On?

Thanks for the response - sorry if this is a super dumb question, but will I be hand-rolling the sequence stuff? Or does that RPi take care of that for me (I think I'm expecting the IO to show up as files or something? Again, I haven't even got my hands on the RPi yet...)
by PLCGuy
Tue Aug 13, 2013 1:30 pm
Forum: Beginners
Topic: Build an Embedded Power Supply?
Replies: 6
Views: 2277

Re: Build an Embedded Power Supply?

btidey wrote:YSearch eBay for 5V industrial power module.
Magic!

It's still looking like it will make more sense for me to cannibalize a USB adapter, but at least now I'm seeing the options I expected - I found lots of 5V 1A power modules in the $4-10 range. So that makes sense...

Thanks for the steer.
by PLCGuy
Sun Aug 11, 2013 1:44 am
Forum: Beginners
Topic: Build an Embedded Power Supply?
Replies: 6
Views: 2277

Re: Build an Embedded Power Supply?

The price difference is because you are going to buy one of each component and assemble it yourself, with each component having been marked up to make a profit at each step of the "supply chain" Makes sense..I just would have assumed that someone would also sell PCB mount or open frame [email protected] power ...
by PLCGuy
Sat Aug 10, 2013 3:48 pm
Forum: Beginners
Topic: Build an Embedded Power Supply?
Replies: 6
Views: 2277

Build an Embedded Power Supply?

Hi, As part of a RPi project, I'm going to be switching 120VAC - probably with an SSR or mechanical relay. Since I'm switching 120VAC and thus need a 120VAC feed into my project enclosure, I'm thinking that ALSO having a separate wallwart/USB 5V supply makes no sense. I figured building a simple 5V ...
by PLCGuy
Sat Aug 10, 2013 3:35 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C / Connecting while On?
Replies: 2
Views: 647

I2C / Connecting while On?

Hi, I'm planning a RPi project (don't actually even have it yet) and I'm wondering about the I2C interface - specifically, does I2C or the RPi allow you to make I2C connections while powered on? In other words, could I hot-swap I2C sensors? Are there precautions I should take (isolate the I2C perhap...
by PLCGuy
Sat Aug 10, 2013 3:31 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Electricity?
Replies: 28
Views: 3877

Re: Electricity?

Current is the amount of electrons that pass a certain point in a circuit per unit of time....This is because electrons are attracted to protons and therefore they 'desire' to move around the circuit. Ahhhh! I think I understand now... So current is just the amount of electrons, not the speed; corr...

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