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Here we go again, trying a blog (again). This is a place for putting small updates to project and things. I have sections on my webpage for projects too but I like to think they are for big updates. Here I will post things I do.

Dial Phone

Projects Posted on 2016-03-31 09:32:58

Many weeks and 1 dead RePhone later….

I have part of a working phone. I did at one point have it all working, with only the RePhone power supply to do. Then It all went wrong and I fried the RePhone. Finally got another one. Now the ringer doesn’t work.

To recap:
Dialling works (for 7 digit numbers)
Receiving calls works
Hanging up works

RePhone not powered from main battery
ringing coils won’t work

I do have the schematics so far.

One think that might be a problem is the transistor to power the boost converter. I really don’t get this but some people use mosfet’s instead might be different some how.

For now I’m going to try and get the RePhone on the main battery power (by feeding it 3.4V not 7.2 this time!) then try and work on this ringing problem.



Mobile phone

Projects Posted on 2016-01-25 21:53:06

So a while (long while) I back the Seeed studio RePhone on kick-starter and it arrived a few weeks back. So I decided to try and put it in an old dial phone. Just imagine it as a mobile you can carry around with you!

Wasn’t impressed with the documentation and instructions on their wiki. Tells you how to install the drivers then kinda just leaves you. Had to do poking in the library header files to find out what i could make it do. Also it does seam to be lacking in functions. There is no check connection or signal strength.

That all said when you find out what you can do it’s really easy. I used the arduino IDE and got it calling in no time.

After finding sparkfuns tutorial where they converted a dial phone to a different GSM board I could get the ringer and dial working.

the mic and speaker where much hard as again the spec on the RePhone is almost nothing. And the SoC that powers it is even more closed. But hey after a lot of playing with large resistors in case I popped something, it finally works :).

That is the current set up. You can make and receive calls. Oh and the bell sound amazing.

Next I want to get it on proto board and try and get it into the phone. then maybe get a PCB made for it.

I do intend on putting the circuits and stuff up so you can see the interesting goo that makes it work. (intend being the word of the moment, you know me and writing).



NOAA weather satellites

Projects Posted on 2015-08-09 10:42:35

A friend showed my this on Hackaday about how to pick up the weather fax signals from NOAA(National Oceanic and Atmospheric Administration) and with a quick bit of research I found you could do it with simple hardware.

Got myself a TV tuner that uses the R820T/R820T2. Then made an antenna out of scrapes I could find at work.

Not the best built antenna around but it looked cool (I do love the look of this antenna type). I tried it inside at first which pretty much failed, the roof at work has metal bits everywhere so scrambled most of the signal.

Not to be discouraged (more the opposite I was so hyper about picking up satellites) we planed to try again the next day, this time outside. Also with the second attempt I did some more reading so I could tweak to the antenna a bit, replace the doggy link to my SDR (TV tuner) and do some proper tracking of the satellites. As it turns out the car park at work is aligned north-south with little building in the way so was perfect location.

Now extremely hyper and having to wait half the day for the pass (think kid on Christmas eve but worse). We assembled outside, setup and wasn’t long till the tones and clicks where heard and the amazing image to the UK started coming though.

WOW it was fantastic, I mean this is about as real time as it gets. Straight from space!

(The Country lines are added my the program)

The data that you can get out of the image converter (WXtoImg) was really good, on the IR image you can mouse over the country and see the temperature. Very interesting to see the top of the clouds are -40degrees ish.

So without saying I’m defiantly trying more RF stuff in the future. (already planing how to pick the higher resolution image).

How I didn’t hear about this before I’m not sure, the NOAA satellites have been there for a long time (1998).

Better get some more data…



KSP rockets

Projects Posted on 2015-06-27 21:42:35

KSP (Kerbal Space Program) //// is awesome! Building, flying and blowing up space craft (mainly blowing up). I was googling around when I came across some amazing blueprints by ZeroFoxWereGiven. And my first thought turned to *That’s perfect for lasering*. Ben Showed me the great KVV mod (Kronal Vessel Viewer) and which you can get flat images of you rockets. With a bit of tweeking with the settings you can get a strong outline.

KVV I used(all just a guide, have a tweak to see if you can get it better):

general settings:

orthographic true

shadow 0

file quality max

Colour adjust:

black 0.0

white 0.33

gamma 0.75

edge detection:

normal power 1.5

depth power 1.5

select offset view to show it staged and stuff. (revert to go back)

Then use the screen shot button to make an image. (saves it in your KSP folder/screenshots).

That’s the KSP bit done.

Now to make it a vector for lasering. I’ve been using inkscape and gimp for this but use what you want. I have been thinking of trying a python version to make it more automated.

There are 2 main steps:

1. creating the etch pattern.

2. creating the outer cut line.

Etch Pattern

Creating the etch pattern is easy. Load the image into inkscape, select Path -> Trace bitmap. Put it in edge detection mode and put 0.250-0.350 in it’s threshold field, again tweaking is required to get the best result (use update to get a preview). Now you may need to select invert depending on the background colour. Click ok and your done, just center it to you page and set the colour to engrave for you laser.

Cut Line

The out line longer. A outline of a combined vector would be nice in inkscape, but for now we will use gimp to help. Import the original image to gimp, use the fuzzy select tool and click near the edge of the rocket. This selected the outside of it. Using the fill tool with fill whole section selected, fill the background white. To fill the rocket do Select -> Invert to select the rocket area, then with the same fill settings fill it black. Export it from gimp (new file better) and go back to inkscape.

In inkscape import that file and Path -> Trace bitmap it, this time we are using brightness cutoff (edge detection creates 2 lines which is bad for cutting). Set the threshold high about 1.00, again inverting may be need. Ok that, then set the colour to cut on your laser. Align to page center like the etch pattern. Now optionally you can use the Path -> Outset tool to move the cut away from the etch. I think 2 Outsets gives a nice finish. But remember to make sure the cut and etch are aligned after out-setting.

Boom we are done. Feed that file to your laser and your done. Lovely rockets to play with or hang on a wall (Playing so much more fun, I pretend).

Next to experiment with is staging

making it stay together in one piece then pull apart as you stage.



Laser upgrade

Projects Posted on 2015-06-15 11:35:51

I’ve been busy in my shed adding new stuff and throwing out a lot of things.

This means I finally got around to put the laser exhaust though a hole in the wall (now I don’t have to open the window each time “yeah”). This being great and all I did cause some problems. Like the lost of air flow. 🙁

As it was getting very smoky when cutting wood and unbearable when cutting acrylic.

I’ve had a small 3 phase Frequency inverter hanging around but never had any motors to run it on. Till now! pulled the capacitor out of the single phase extractor (single phase motor are just 3 phase ones with a capacitor) and bingo a nice motor to put on it.

Firing up the inverter to 50Hz all works fine then for the real test how fast will it go till it starts slipping.

Winding it up I got it to 95Hz before it started slipping and slowing down and wow much more air flow. You can feel it sucking though the front vent. It does make lots more noise but it’s variable so I can turn it back down again.

After test cutting some acrylic the smell was still bad but not nearly as bad as before. (I’m sure lased acrylic is very bad for you).

Lots of laser fun to come.

Pictures:

Tom