I have assembled a circuit of the work-in-progress "Interactive Frequency Reader" and weighted it: about 90 grams without the CAT cable to the FT-817.
This weight includes the circuitry, the 16x2 LCD and the 4x4 matrix keyboard.
Must not forget to add the enclosure weight too!
The assembled circuit confirms that the hardware design has reached a stable version, as well as basic firmware functions. Now I have to think of a user friendly, menu driven?, interface.
08 January 2011
05 January 2011
Macro for cameraphone from viewfinder lens
I have come across an article on Hack a Day about building and adding a macro lens to a cameraphone at almost no cost. It requires a lens from the laser head of a DVD reader, and according to published pictures and tutorials, we are talking about a very small part.
While looking inside the 35mm camera (see previous post), I gained access to some lenses and ... guess what? There's one that can be used as a macro extension for a cameraphone!
It is the viewfinder lens, the one where the photographer was looking into before the digital camera era. It is larger than the DVD laser head, so it is easier to handle and mount on an adapter (to be constructed).
This addition works by reducing the minimum distance at which the camera can focus, so that you can get closer to the subject and in fact capture more details.
Let's see how my 3.2 Mp F2.8 auto focus cameraphone behaved when holding the macro lens in front of it.
The sample was a 2 €cent coin at sunset, that you can see here side by side to the lens:
(picture shot without the macro lens, obviously)
Let's hold the lens in front of the camera and get an interesting detail (click on pictures to see them 1:1):
Or, zooming in at full resolution on the focused area:
If I had shot at the same distance but without the macro lens, this would have been the result:
As last, with and without the macro lens side by side:
Now I have to figure out a way to hold the lens in front of the camera.
While looking inside the 35mm camera (see previous post), I gained access to some lenses and ... guess what? There's one that can be used as a macro extension for a cameraphone!
It is the viewfinder lens, the one where the photographer was looking into before the digital camera era. It is larger than the DVD laser head, so it is easier to handle and mount on an adapter (to be constructed).
This addition works by reducing the minimum distance at which the camera can focus, so that you can get closer to the subject and in fact capture more details.
Let's see how my 3.2 Mp F2.8 auto focus cameraphone behaved when holding the macro lens in front of it.
The sample was a 2 €cent coin at sunset, that you can see here side by side to the lens:
(picture shot without the macro lens, obviously)Let's hold the lens in front of the camera and get an interesting detail (click on pictures to see them 1:1):
Or, zooming in at full resolution on the focused area:
If I had shot at the same distance but without the macro lens, this would have been the result:
As last, with and without the macro lens side by side:
Now I have to figure out a way to hold the lens in front of the camera.
04 January 2011
What is inside a 35mm point&shoot camera
After few days in the hands of my daughter, a point and shoot 35mm camera plastic has started to break apart... time to put it aside and start opening it up.
It was a Minolta Riva Zoom Pico with a motorized 35-60mm zoom lens and autofocus. It did allow me to experiment with photography, and it took good pictures.
Anyway, I never opened up a photocamera, so I was curious to see what was inside.
I was surprised to find "enough" electronics, all mounted on a flexible PCB fit between the inner body and the outer shield. The electrolytic capacitor of the flash (220 uF, 300 V) was fit inside the film roll cylinder: a very smart arrangment. Everything was a tight fit and I bet it was hand assembled back in 1994 or so. What else can be taken off and recycled? Here's a list:
The zoom objective has many wires making it almost impossible to control it from the outside (zoom, focus and shutter), so it is stuck in the "rest" position.
Lenses can be used to experiment with light.. maybe one of the small biconvex lenses from the autofocus could focus the Sun and set something on fire?!
Last but not least, around the camera body there are some metallic springy contacts that could become a Morse key.
It was a Minolta Riva Zoom Pico with a motorized 35-60mm zoom lens and autofocus. It did allow me to experiment with photography, and it took good pictures.
Anyway, I never opened up a photocamera, so I was curious to see what was inside.
I was surprised to find "enough" electronics, all mounted on a flexible PCB fit between the inner body and the outer shield. The electrolytic capacitor of the flash (220 uF, 300 V) was fit inside the film roll cylinder: a very smart arrangment. Everything was a tight fit and I bet it was hand assembled back in 1994 or so. What else can be taken off and recycled? Here's a list:
- flash strobe with circuitry
- small screws
- whitworth 1/4" nut (plastic)
- small plastic gears
- DC stepper motor
- lenses
- (zoom) objective
- photoresistor
- IR LED
- 200 pixel sensor from the autofocus
The zoom objective has many wires making it almost impossible to control it from the outside (zoom, focus and shutter), so it is stuck in the "rest" position.
Lenses can be used to experiment with light.. maybe one of the small biconvex lenses from the autofocus could focus the Sun and set something on fire?!
Last but not least, around the camera body there are some metallic springy contacts that could become a Morse key.
27 December 2010
LCD and contrast (HD44780)
I want to issue a word of caution about the contrast pin wiring on HD44780 compatible liquid crystal displays.
All my diagrams show the contrast pin going directly to ground: that's how my display works. Any voltage level higher than that makes the contrast too light and display unreadable.
Other displays need an intermediate voltage, so you better check out how yours works before soldering it in place! The datasheet might be a good starting point.
These displays will be used on my FT-817 Frequency Reader and Interactive Frequency Reader projects, so I will have to be careful too. ;-)
All my diagrams show the contrast pin going directly to ground: that's how my display works. Any voltage level higher than that makes the contrast too light and display unreadable.
Other displays need an intermediate voltage, so you better check out how yours works before soldering it in place! The datasheet might be a good starting point.
These displays will be used on my FT-817 Frequency Reader and Interactive Frequency Reader projects, so I will have to be careful too. ;-)
10 December 2010
Cellphone remote control, just an idea
A very close family member has asked me how it would be possible to switch on (electric) heating in a remote location. Through a phone call, of course, I replied. Requirements are pretty simple: I would have to close a relay, maybe open it back.
The location has a landline, but I have not found useful references online on how to interface with it (is that considered a pre-Internet era technology?!). So, let's go mobile.
Take a cellphone that allows to customize the ring tone depending on the caller:
Next, build some simple hardware to detect those two tones and throw them into a simple set/reset system that drives the relay. Or make it with a microcontroller. The latter solution would allow some feedback on the relay state if the cellphone can be configured to auto-answer a call: let the circuit emit two different sounds depending on the relay state (or Morse code!). Maybe don't let it beep forever, so neighbors won't get annoyed.
Note that this "interface" can be arranged without harming a cellphone, because the audio coupling can occur over the air (yes, the location is quiet and empty).
Let me look for some sound recognition sample code for AVRs... :-)
The location has a landline, but I have not found useful references online on how to interface with it (is that considered a pre-Internet era technology?!). So, let's go mobile.
Take a cellphone that allows to customize the ring tone depending on the caller:
- associate a fixed tone sound to one calling number: this will be the "ON" triggering event;
- associate a different fixed tone sound to another calling number as "OFF" triggering event;
- associate a third, no-sound, ringtone to all other numbers (default).
Next, build some simple hardware to detect those two tones and throw them into a simple set/reset system that drives the relay. Or make it with a microcontroller. The latter solution would allow some feedback on the relay state if the cellphone can be configured to auto-answer a call: let the circuit emit two different sounds depending on the relay state (or Morse code!). Maybe don't let it beep forever, so neighbors won't get annoyed.
Note that this "interface" can be arranged without harming a cellphone, because the audio coupling can occur over the air (yes, the location is quiet and empty).
Let me look for some sound recognition sample code for AVRs... :-)
29 November 2010
The Joule-Doh night light
What do you get if you take a joule-thief and put it inside a play-doh can? A yellow "Joule-Doh" light! (or a "Play-Thief" one?!)
Recently I have re-engineered my homebuilt joule-thief after a too heavy shake that broke one wire. It was a good chance to let my older daughter choose for a new container, and a new color.
An empty play-doh can laying around was chosen as the new night light. The lid holds just right a 1xAA container and a small SPST slide-switch. Wires hold up the LED.
The 5mm while LED gives a quite directional light beam, but the transparentish can allows the light to be diffused around.
The Joule-Doh night light generates enough brightness in a dark 4x5m room so that you can walk around without hitting abandoned toys and tuck your child(ren) up.
For those not familiar with the "Joule thief", it is an oscillating circuit that allows to light a LED out of a 1.5V battery (be it AA, AAA or button). It usually works down to 0.8V, so it is a very good way to drain all the juice from those batteries that won't work anymore in normal toys. This one has been running already for 5 nights off the same "officially discharged" AA battery.
Recently I have re-engineered my homebuilt joule-thief after a too heavy shake that broke one wire. It was a good chance to let my older daughter choose for a new container, and a new color.
An empty play-doh can laying around was chosen as the new night light. The lid holds just right a 1xAA container and a small SPST slide-switch. Wires hold up the LED.
The 5mm while LED gives a quite directional light beam, but the transparentish can allows the light to be diffused around.
The Joule-Doh night light generates enough brightness in a dark 4x5m room so that you can walk around without hitting abandoned toys and tuck your child(ren) up.For those not familiar with the "Joule thief", it is an oscillating circuit that allows to light a LED out of a 1.5V battery (be it AA, AAA or button). It usually works down to 0.8V, so it is a very good way to drain all the juice from those batteries that won't work anymore in normal toys. This one has been running already for 5 nights off the same "officially discharged" AA battery.
12 November 2010
TTL oscillator as NE602 external source
There are lazy moments in everyone's life when you want to drive the NE602 LO input with a TTL-generated signal. I had asked on the qrp-tech forum few months ago and got helpful replies.
NE602 datasheet reccommends a 200 to 300 mV p-p drive from an external LO.
An application note shows this arrangment with a resistive divider for a TTL signal: 510 and 30 ohm, fed through a 0.1uF capacitor. This results in 277 mVpp for a 0-5V square signal.
Simple, isn't it?
Since I ignore the output switng of the canned oscillator I intend to use, I will try with a 1k multiturn trimmer and tune for an acceptable level.
NE602 datasheet reccommends a 200 to 300 mV p-p drive from an external LO.
An application note shows this arrangment with a resistive divider for a TTL signal: 510 and 30 ohm, fed through a 0.1uF capacitor. This results in 277 mVpp for a 0-5V square signal.
Simple, isn't it?
Since I ignore the output switng of the canned oscillator I intend to use, I will try with a 1k multiturn trimmer and tune for an acceptable level.
08 November 2010
FT817 external display, video instructions (it)
Today I think that there is no better way than a video to show a product's features, and to get some feedback about it.
So I produced 5'30" worth of video-instructions for the external frequency readout for transverter users. The audio is in Italian and I will add English subtitles.
Current features were summarized in another post. Please send feedback via email.
So I produced 5'30" worth of video-instructions for the external frequency readout for transverter users. The audio is in Italian and I will add English subtitles.
Current features were summarized in another post. Please send feedback via email.
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