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Friday, 23 October 2020

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Gramophone for smartphone, crystal radio and bluetooh speakers.





This is a gramophone that can use physical methods to amplify the sound acoustically. There are separate modules for this to work with smart phone, crystal radio or even to plug in a bluetooth module and speaker. You can make it a 3-in-1 set up. Checkout my youtube video  for the demonstration






You can find the 3D print files here:

The rectangular version




https://www.thingiverse.com/thing:4631838



The round version

https://www.thingiverse.com/thing:4631861

Tuesday, 20 October 2020

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Passive Vertical Hydroponics Tower

 


I am designing a passive vertical hydroponics system. Unlike conventional tower gardens or similar vertical tower system, this one will not recycle. I hope to use the passive non-recycling system to provide a more nature, yet reasonable harvest without electricity (except the grow light when required).


The system is a passive non recycling system. All nutrient will be absorbed by the plant. Nothing will be throw away. Nothing will be wasted. It’s a modified version of the Kratcky method. 


While the Kratcky method require you to find a tank big enough to provide all the Nutrients required by the growth of the plant from seedling to harvest, this method allow you to continue to replenish the nutrient throughout the life of the plant.

This is well suited for thirsty plants such as fruits, water melon, etc.


Check out my video to see the plan and my description and some concerns I have.
Feel free to give me your comment so I can improve my design.




You can find latest 3D print files here.

Beware that I may update them while I continue to test and improve.

https://www.thingiverse.com/thing:4629135


The TowerUnitiwthPipe can only be printed on 3D printers with 300x300x200mm print beds

If you only have a 200x200x200mm 3D printer, then you need to print the base unit with holes, and six pipes. Then stick them together with glue.


Other parts can be printed with 200x200x200mm print beds.


The TowerUnitiwthPipe can only be printed on 3D printers with 300x300x200mm print beds. 

Other parts can be printed with 200x200x200mm print beds.



    
Top cover



The reservoir if you want to automatic water level controller to feed all tanks from the reservoir.

    
         This is  actually the PVC 160mm pipe. Or you can print it too. for separating tanks from one another if you fear they are too close together. 





Non-3D Print version




The other way to build this passive vertical hydroponics system is to use PVC pipe.
I am trying to make one using a 1.5 meter long 160 mm PVC pipe. I am going to use the 45 degree 32mm PVC elbow joints to hold the grow baskets. The good thing is I just need to drill 38mm holes on the big pvc pipe and put in PVC glue to stick them up. 

For the water tank at each of the layers(total 5), I will drive some long screws into the big pvc pipe to hold the 145mm diameter 4 inches deep plastic micro wave box in place. That will make a good nutrient tank to hold an inch deep of nutrient solutions. Then insert inverted nutrient bottles to refill the nutrient tank using the gravitational pull and keep the 1 inch water level by air pressure. Like what I showed in my video. 

The advanced version will have a big water tank at the top to supply nutrient down to each nutrient tank at each layer. A mini float valve designed by me will be used to control nutrient level to within 1 inch. A bit like the autopots method. 

The only draw back of using this 1.5 meter long pvc pipe is that maintenance may be hard compare to using stackable buckets of similar size. May need to open some maintainable doors in between the layers to do that.



Supporting my work

If you like my work and want to see more of these, you can use one of these methods to support my work.

  • Click through my Amazon and e-Bay links to order components you need to build the projects I shared. By going through my links to order, there will not be a price difference to you, but I will get paid a tiny amount by Amazon or e-Bay to support my work.


Parts to order for this project

Amazon


   





eBay







Sunday, 18 October 2020

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3D designed Gramophone for Crystal Radios

 3D Designed Gramophones for Crystal Radio





Inspired by some images of antique gramophone speakers, I designed this 3D printed gramophone horn and the base that goes with it. You can install a crystal radio mouth piece/headphone piece a the base to drive the horn speaker. The horn will amplify the sound a bit physically. I enjoyed the sound that comes out of it. It gives you  a taste of the antique versions if you cannot afford one form the Museum.

All the files can be downloaded from my thingiverse like below:

https://www.thingiverse.com/thing:4626950







Checkout this Youtube video that has a link to my blog post for more details and the link to download the 3D design files and how to print. I also suggested some horn speaker drivers (see Amazon links below) that are closer to 100dB or more that is more suitable for Crystal Radios. However, you do need to have a very strong signal to drive the speakers, i.e. after detection DC current of 100uA or above. You also need an audio impedance matching transformer like that of T751 or KPB-02 (e-Bay links below) to step down the impedance from crystal radio to that of the 8 ohm speaker.


Enjoy!












Supporting my work

If you like my work and want to see more of these, you can use one of these methods to support my work.

  • Click through my Amazon and e-Bay links to order components you need to build the projects I shared. By going through my links to order, there will not be a price difference to you, but I will get paid a tiny amount by Amazon or e-Bay to support my work.


Parts to order for this project

Amazon


   





eBay

Crystal Radio Impedance Matching Box Installation Kit KPB-02 from 200KΩ to 4Ω














Other parts you may also be interested to order

NiZn Ferrite Rod R40C1- 200x10mm for High Q Amateur & Crystal Radio Coils, AM SW


10x100mm Black MnZn Ferrite Rod Bar Loopstick For Crystal Radio Antenna Aerial B



10x100mm Black MnZn Ferrite Rod Bar Loopstick For Radio Antenna Aerial Crystal


Litz Wire for AM Crystal Radio Coil

MOS FET 3SK-143-Q (3DQ), a good detector for very weak signals in AM, SW or FM Crystal Radios.


To make high Q LC circuits for Variometer Crystal Radio

TC 600F Series 560pF Ultra-Low ESR High Q NPO RF & Microwave Capacitors 10PCS


ATC 100B471 RF Porcelain Superchip Multilayer Capacitors 470pF 500V 10PCS

ATC 100E301 300pF Porcelain Multilayer High RF Power Capacitors MLC

To make a variable inductor for AM crystal radio with ferrite rod

NiZn Ferrite Rod R40C1- 200x10mm for High Q Amateur & Crystal Radio Coils, AM SW


10x100mm Black MnZn Ferrite Rod Bar Loopstick For Crystal Radio Antenna Aerial B



10x100mm Black MnZn Ferrite Rod Bar Loopstick For Radio Antenna Aerial Crystal

A low cost high quality 3D Printer that I recommend.
Official Creality Upgrade Ender 3 V2 FDM 3D Printer with Meanwell Power Supply Silent Motherboard Carborundum Glass Platform and Build Volume 220 x 220 x 250mm


To DIY a good quality crystal radio earbud from a piezo-electric buzzer that has equal or even better performance than a genuine crystal radio earbud 6 Pack 3-24v Piezo Electric Tone Buzzer Alarm dc 3-24 v for Physics Circuits Continuous Sound Genuine Crystal Radio Earbud (warning - for reference only, these earbuds often got connectivity issues where the contact with the internal disc is loose and will loose after a few months of use and hard to repair. So, it may be much better to DIY one using the buzzer (see above). However, if you just want to have a few of the genuine crystal radio earbud, it’s no harm to buy one for collection purposes knowing that it may fail in some time due to contact loosening issues). Crystal Radio Earphone, High Impedance, 3.5mm jack Philmore Crystal Radio Earphone to Stripped and Tinned Bare Wire, 7-Ft Cord, High Impedance 748 Germanium Diodes for AM Crystal RadioMCIGICM 20Pcs 1N34A 1N34 Germanium Diode 50mA 65V DO-35 (DO-204AH) Axial Schottky Diodes for AM Crystal Radio10 pcs of 1N60P 1N60 SCHOTTKY DIODE 45V 30mA

Enameled copper wire for winding coils for crystal radios

BNTECHGO 22 AWG Magnet Wire - Enameled Copper Wire - Enameled Magnet Winding Wire - 4 oz - 0.0256" Diameter 1 Spool Coil

BNTECHGO 24 AWG Magnet Wire - Enameled Copper Wire - Enameled Magnet Winding Wire - 4 oz - 0.0197" Diameter 1 Spool Coil Red

BNTECHGO 28 AWG Magnet Wire - Enameled Copper Wire - Enameled Magnet Winding Wire - 4 oz - 0.0122" Diameter 1 Spool Coil Red

References to my other relevant projects

The 3D Printed FM Variable Capacitor Crystal Radio



There are total 5 videos.

Part 1 - Part 4 shows you how to design the 3D models from scratch step by step using Fusion 360.

Part 5 show you how to print the  FM crystal radio parts, build the radio and test it

1. Gears - Fusion 360 design for FM Crystal Radio https://youtu.be/lD4o_e0yzv8

2. Variable Capacitor - Fusion 360 design for FM Crystal Radio https://youtu.be/0-uAgbBQEIc

3. Drill holes on board - Fusion 360 design for FM Crystal Radio https://youtu.be/CPbD4M-2zU4

4. Animation and print layout - Fusion 360 design for FM Crystal Radio https://youtu.be/LM7qXn05I-c

5. Build and Test FM Crystal Radio - Fusion 360 design https://youtu.be/84h14JCvMds







Tuesday, 6 October 2020

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 3D Designed Ferrite Rod Variometer Crystal Radio 










I first learnt about 3D printing when I tried to reproduce a fountain pen crystal radio from the early dates. I used 3D design software fusion 360 (free of charge) to create my first model. That was a bit too complex for beginners as it has to do with fitting threads around the body of the fountain pen and adjusting the fitness so they are not too tight or too loose.  The threads allow the turning and pulling of the ferrite core in and out of the coil to vary the inductance to tune the different frequencies within the AM /MW radio band.

This is a second design which I thought will be much easier. However,   I ended up spending a whole week on the details. This time instead of the threads, you have to deal with the gears. A spur wheel gear interacting with a rack gear sliding on two guiding pins. Luckily fusion 360 has a gear tool that you can download to create the gear you want. Fix  the size and the number of teeth to go onto the gear, click a button, then you are done. However, that add-on tool can only be  run on windows not MACs.  I am a MAC guy,  I need to borrow my wife's windows computer to finish it. There are other non-windows tools from fusion 360 you can use. But sadly these does not support customisable rack gears. 

Back to my design. The challenge of this design is to make the walls of the  frame of the coil as thin as possible and as close to the ferrite core as possible so the resulting inductance can vary from the minimum to the  maximum which is more than 9.5 times that of the minimum. This range will cover the broadcast frequency range of most radio stations in MW (535 Khz to 16500 Khz . Otherwise, you will need to add a band switch to select which one of the two fixed capacitor you need to pair up with to make up for the deficiency in frequency ranges. 

I ended up with a variable inductance range of 8 times only , from 30uH to 209uH. So I decided to add the band switch and two fixed capacitor C1 and C2 in the end.  Sometimes, even though your calculation is right, there are so many factors in field tests that will impact the frequency range. E.g. antenna impedance matching, and grounding etc. So, it'll be good to design the radio with a band switch just in case.

Later on I added this other design for a rounded ferrite core (10mm x 100mm)


3D Design files

You can find the 3D design files here.


For round ferrite rod 10x100mm

https://www.thingiverse.com/thing:4592871



For rectangular ferrite rod 55x13x5mm






Youtube Video Instructions

More instructions in the youtube video here.

Part 1 - Introduction and demo



The Circuit



The circuit is the same as that of the ferrite rod version of the variometer radio.

The circuit supports three types of detectors: Crystal, Diode and MOS FET (3DQ).
MOS FET (3DQ, aka 3SK143-Q) is my preferred choice of detector that outperforms the diode and crystal in weak signal detection. Read more about 3DQ here.

I draw the same circuit two times to show you how to wire this up for 3DQ (top digram), and crystals and diodes (bottom diagram).  The tabbing point , the exact turn on the coil that you need to connect to the diode depends on the what diode or crystal you want to use (the impedance of the diode) and the signal strength. The top of the coil in the circuit diagram that is the furthest away from the circuit ground (the symbol represented by three horizontal lines) is called the HOT end of the coil. The turn that closest to the circuit ground is called the COLD end of the coil. 

The tabbing point

In general, you connect the detector input to a turn of the coil closer to the HOT end when:
  • you want more sensitivity but less selectivity
  • the input impedance of the detector is higher (e.g. in 3DQ, G2 has high impedance so connect directly to the HOT end which is 55 turns form the COLD end).
  • the signal strength is weaker.
In the contrary you connect the detector input to a turn of the coil closer to the COLD end when:
  • you want more selectivity but less sensitivity 
  • the input impedance of the detector is lower  (e.g. in 3DQ, S has a low impedance so connect it to the 5th turn from the COLD end).
  • the signal strength is higher.

The Variometer

The conventional way to tune the frequency of a radio is by turning a knob to change the capacitance of a variable capacitor. In the old days, electronic components are very expansive. Variable capacitors were expensive and easily available. Armatures had overcome this by using a variable inductor a.k.a. variometer that paired up with a fixed capacitor.

Latter on , as variable capacitors become more abundant and cheaper and available to armatures, everyone forgot about Variometers.

Recently, as the technology advances and digital radios were more abundant,  manufacturing of variable capacitors have declined and less available to the armature radio markets. It becomes harder for armatures to get hold of good quality variable capacitors that is suitable for crystal radios.
That's why, I started creating these variable inductance crystal radios using ferrite cores.

The range of variable inductance.

To allow us to tune across  entire frequency range in the AM broadcast from 525Khz to 1705Khz, you need a variable inductor that can cover the corresponding range of inductance. 

What is this range ?

Using the resonance frequency formula, 


the corresponding range of inductance to achieve will be 
the square of (1705Khz/525Khz) which is ~ 10.55 times.
i.e. if the minimum inductance of your variometer is 40uH, the maximum inductance need to be at least 422uH to be able to cover the entire AM broadcast range.

This is not achievable by air core variometer.
This can be achievable by ferrite core variometer. However, the core and the wire that make up the turns of the coils must be very close together. 

The precision of 3D printed parts are lower then manufactured products, hence I need to leave a bigger gap (of 1.5mm) between the walls of the ferrite rod and the curved coil wiring frame. This gap reduces the frequency range of the variometer down to only  6.

Hence we need to add a band switch to pair up the coil to two different fixed capacitors C1 and C2.


The value of C1 and C2 depends on the minimum and maximum inductance of the coil, which depends on the number of turns, the size of the ferrite rod  and the dielectric and permeability values of the ferrite material being used.

If you use the conventional ferrite core material PC40 with an initial permeability of around 2000, then you will need less turns, and smaller values of C1 and C2.

If you use the high Q ferrite core R40C1, with an initial permeability of only 100, then you will need more turns and higher values of C1 and C2.


What is Litz wire



Litz wire is a special type of multi-strand  wire or cable that are insulated by silk or cotton from one another. This is used in electronics to carry radio frequencies to reduce the skin effect and proximity effect losses in conductors used at frequencies up the end of the AM radio frequency spectrum.

That's why Litz wire is not suitable for radio frequencies at SW (HF) or FM (VHF)  as the inherent stray capacitance in between the multiple insulated cores lowered the tuned frequency and make it impossible to be used in such radios.


Hence, Litz wire of the same diameter outperforms the  enameled copper wire (aka magnet wire) when used in coils for AM radio frequencies.



Supporting my work

If you like my work and want to see more of these, you can use one of these methods to support my work.

  • Click through my Amazon and e-Bay links to order components you need to build the projects I shared. By going through my links to order, there will not be a price difference to you, but I will get paid a tiny amount by Amazon or e-Bay to support my work.


Parts to order for this project

NiZn Ferrite Rod R40C1- 200x10mm for High Q Amateur & Crystal Radio Coils, AM SW


10x100mm Black MnZn Ferrite Rod Bar Loopstick For Crystal Radio Antenna Aerial B



10x100mm Black MnZn Ferrite Rod Bar Loopstick For Radio Antenna Aerial Crystal


Litz Wire for AM Crystal Radio Coil

MOS FET 3SK-143-Q (3DQ), a good detector for very weak signals in AM, SW or FM Crystal Radios.

Other parts you may also be interested to order

A low cost high quality 3D Printer that I recommend.Official Creality Upgrade Ender 3 V2 FDM 3D Printer with Meanwell Power Supply Silent Motherboard Carborundum Glass Platform and Build Volume 220 x 220 x 250mm

To make high Q LC circuits for Variometer Crystal Radio

TC 600F Series 560pF Ultra-Low ESR High Q NPO RF & Microwave Capacitors 10PCS


ATC 100B471 RF Porcelain Superchip Multilayer Capacitors 470pF 500V 10PCS

ATC 100E301 300pF Porcelain Multilayer High RF Power Capacitors MLC

To make a variable inductor for AM crystal radio with ferrite rod

NiZn Ferrite Rod R40C1- 200x10mm for High Q Amateur & Crystal Radio Coils, AM SW


10x100mm Black MnZn Ferrite Rod Bar Loopstick For Crystal Radio Antenna Aerial B



10x100mm Black MnZn Ferrite Rod Bar Loopstick For Radio Antenna Aerial Crystal

A low cost high quality 3D Printer that I recommend.
Official Creality Upgrade Ender 3 V2 FDM 3D Printer with Meanwell Power Supply Silent Motherboard Carborundum Glass Platform and Build Volume 220 x 220 x 250mm


To DIY a good quality crystal radio earbud from a piezo-electric buzzer that has equal or even better performance than a genuine crystal radio earbud 6 Pack 3-24v Piezo Electric Tone Buzzer Alarm dc 3-24 v for Physics Circuits Continuous Sound Genuine Crystal Radio Earbud (warning - for reference only, these earbuds often got connectivity issues where the contact with the internal disc is loose and will loose after a few months of use and hard to repair. So, it may be much better to DIY one using the buzzer (see above). However, if you just want to have a few of the genuine crystal radio earbud, it’s no harm to buy one for collection purposes knowing that it may fail in some time due to contact loosening issues). Crystal Radio Earphone, High Impedance, 3.5mm jack Philmore Crystal Radio Earphone to Stripped and Tinned Bare Wire, 7-Ft Cord, High Impedance 748 Germanium Diodes for AM Crystal RadioMCIGICM 20Pcs 1N34A 1N34 Germanium Diode 50mA 65V DO-35 (DO-204AH) Axial Schottky Diodes for AM Crystal Radio10 pcs of 1N60P 1N60 SCHOTTKY DIODE 45V 30mA

Enameled copper wire for winding coils for crystal radios

BNTECHGO 22 AWG Magnet Wire - Enameled Copper Wire - Enameled Magnet Winding Wire - 4 oz - 0.0256" Diameter 1 Spool Coil

BNTECHGO 24 AWG Magnet Wire - Enameled Copper Wire - Enameled Magnet Winding Wire - 4 oz - 0.0197" Diameter 1 Spool Coil Red

BNTECHGO 28 AWG Magnet Wire - Enameled Copper Wire - Enameled Magnet Winding Wire - 4 oz - 0.0122" Diameter 1 Spool Coil Red

References to my other relevant projects

The 3D Printed FM Variable Capacitor Crystal Radio



There are total 5 videos.

Part 1 - Part 4 shows you how to design the 3D models from scratch step by step using Fusion 360.

Part 5 show you how to print the  FM crystal radio parts, build the radio and test it

1. Gears - Fusion 360 design for FM Crystal Radio https://youtu.be/lD4o_e0yzv8

2. Variable Capacitor - Fusion 360 design for FM Crystal Radio https://youtu.be/0-uAgbBQEIc

3. Drill holes on board - Fusion 360 design for FM Crystal Radio https://youtu.be/CPbD4M-2zU4

4. Animation and print layout - Fusion 360 design for FM Crystal Radio https://youtu.be/LM7qXn05I-c

5. Build and Test FM Crystal Radio - Fusion 360 design https://youtu.be/84h14JCvMds








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Gramophone for smartphone, crystal radio and bluetooh speakers. This is a gramophone that can use physical methods to amplify the sound acou...