Farnsworth Discussion

[BeachcomberBob]

Hi Airhead,

I got the guts out of a 'video brochure' or greetings card (from China) to handle the videos, controlled by the rotary switch instead of the supplied push buttons. The sample I was sent had the capability of playing 5 different AVI files (but one of those plays automatically at switch-on, so I've made it blank/black). The other four I've put in a repeat pattern around the dial, so from positions 5-12 you get the same ones again. I suppose that, if I were making a production run of it, I could get the Chinese supplier to create a PCB capable of playing 12 videos (for a price!) The biggest problem I had was finding an LCD screen of the right proportions. Nobody seems to make square or 4:3 aspect any more - every man and his dog has gone wide-screen. In the end, I turned both screen and PCB sideways and just edited my videos to play sideways-on, with a circular fading filter.


The 'ringer' is the guts from a programmable 'talking' birthday card, with the mp3 embedded into it, with a 'home brew' latch circuit driven by the transceiver PCB.

 

[BeachcomberBob]

Just found a picture I took of the video brochure board, when in it was in the design and test phase. The header plugs were for fast assembly/disassembly of the various other components whilst testing, but they all had to be replaced by hard wiring due to the space constraints.



Top right is the USB header, then speaker + volume controls (which I did away with). Bottom edge right is power, then the connectors for the push button video selection. There's a whole heap of connections far left that I never could get to do anything without a circuit diagram (most probably programmable by the manufacturer for extra videos).

 

[BrotherWilliam]

Very impressive! Great work on getting the clips to show up on the screen.

 

[Fyberdyne Labs]

I made a vacuume formed lens for my 1st Farnsworth. I was using a white push light. Here is a clear one:

- - - Updated - - -

And here is a white one installed:

 

[The Schlitzie]

That looks awesome!

Without access to a laser, I had to photo etch my brass in one go like a p.c.b., including all the holes and slots. Tip: To 'antique' it, try leaving kitchen paper towel, soaked in caustic soda solution, in haphazard clumps for a few minutes. (Make sure you rinse well after - and wear gloves!)

View attachment 334965

 

[BeachcomberBob]

My lens came out of a cheap hygrometer (from Hong Kong) that I got off Ebay for $1.99 (inc. shipping).

The lens had a ready-made lip just perfect for gluing to the back face of the brass plate.

 

[BeachcomberBob]

Did you find that the white was too white? I'd be tempted to use a frosted clear plastic (or painted effect inside - Rustoleum do a spray) then back it with a black fabric or paper to give that cathode ray tube feel.

 

[Fyberdyne Labs]

The white one I used is just a test. I plan on using the clear one painted on the inside. I might make a white inter lens air brushed to look more like an older TV screen.

 

[BeachcomberBob]

Just dug out a scrap clear lens and did a quick test of how window frosting spray paint would look with regards to simulating a CRT. I backed it with black card, flat to the rim rather than hard onto the back surface of the lens. This was two coats, which I think is too frosty. It does go on quite clear, but frosts more as it hardens, hence me doing the second coat.

 

[snouty]

I thought I read something in Project Runs about another possible run of the Farnsworth Brass Faceplates?

Brass Farnsworth Faceplates (Russrep)
ED

Actually, is this a thing? Is anyone fabbing faceplates? There was this one guy on Etsy, lasergarage, who made some really quite good faceplates in plastic, and I got all excited . . . . but his garage burned down destroying everything, the laser, the computer with the files on, the garage itself. Everything.

Anyone else making prefabbed faceplates before I embark on making my own?

best regards

Phil

 

[Marsupial]

Actually, is this a thing? Is anyone fabbing faceplates? There was this one guy on Etsy, lasergarage, who made some really quite good faceplates in plastic, and I got all excited . . . . but his garage burned down destroying everything, the laser, the computer with the files on, the garage itself. Everything.

Anyone else making prefabbed faceplates before I embark on making my own?

best regards

Phil

I'd like to know too, as the only source I had found was lasergarage. Does he not have insurances?

Short on making the faceplate by hand, are there any current options?

 

[snouty]

I'd like to know too, as the only source I had found was lasergarage. Does he not have insurances?

Short on making the faceplate by hand, are there any current options?

As far as I know he lost everything but was insured, but only personal stuff he had in the garage not the laser cutter or the computer with the files on.

 

[Emperoroz]

Hello! I just joined and after reading through your work I was just too tempted to build my own. After some research and product testing, I have designed and prototype tested working farnsworth models that transmit and receive video and audio as well as ring and use the screen off and on sounds. I will load some preliminary photos and send more detailed work as I continue!

I decided to use an aluminum box available on eBay for 10 dollars. I've also used a plastic dome from a hygrometer.

The screen is a dissected backup camera and I have a tiny fm modulator and demodulator hooked up to tiny lithium polymer batteries. The hope is to charge them wirelessly like an electric shaver [induction].

Thoughts? :]


Testing transmit receiver assemblies

 

[The Schlitzie]

wow...umm, more pics!

Looks like a Farnsworth electronics kit in the making! opcorn

 

[Emperoroz]

The best part is I've only spent 75 dollars on it so far for the equipment. And I don't anticipate much trouble etching my own faceplate. Really guys there's this toner based etching technique that makes the process pretty painless after you cut out the panel :]

 

[Emperoroz]

This is the hardware I'll be using. In the top left side of the case is the receiver and transmitter. They are a 4 channel, 500 meter range, video and audio transmitter and receiver. This means I can wire up the center knob to change channels. (Rotary switches aren't made small enough so I'll be making one from PCB. Below the transmitter and receiver on the left in my case is the web camera. It's actually smaller than that once you take the plastic off. The screen is from a back-up camera set-up. All of these things when working together draw about 900mAh. I've ordered three 3.7v 1200mAh batteries. They are wafer thin and with a coil and bridge rectifier, could charge wirelessly in a cradle set-up. Not seen is the three small 10 second record/playback circuits. These will be the "screen on" "screen off" and "bzzz bzzzz!" sounds!

How it will Operate
The unit 'main power' will be the knob on the far left.

The 'screen power' and 'screen on sound' will be operated by reed (magnetic) switch in the farnsworth. This means the screen, screen sound, transmitter and camera automatically turn on when you open the box. The receiver and audio are always 'on' (they only draw about 150mah)

The black push-button will be rigged to a 10 sec recording circuit which will play back the buzzing sound and light up the red light. The alert will not be heard, just transmitted through the transmitter to the receiving unit.

It will still all have to be carefully shoe-horned in but the transmitter and receiver are small enough that I think this will work. I just hope the range is substantial. Maybe I'll use the side jacks for an extended antenna you can plug in. So far I've tested the unit to 70 feet with little distortion. (though distortion looks awesome)


EmperorOz

 

[v137a]

Today, from the workbench, I bring you four tips:

1) Don't work tired. You'll forget things. Important things. Things you know and will want to remember, like that drill bits come in increments smaller than 1/16".
2) In the event that you do work tired, don't do irreversible steps like drilling holes or removing material. Because sometimes, you remove too much.
3) If you're working tired and drilling the side holes in your fly box and you've lost the packaging for the jacks and you can't remember the size of the hole you need, but you know the 5/16" hole you just made isn't large enough, don't jump right on up to 3/8". That's not the hole you want. Drilling that hole will make you think you've ruined your expensive fly box.
4) In the event that, like me, you've drilled the holes too large and you can't find a suitable washer or grommet to fill the gap and you don't want your jacks to be flush, there is another option, and it's at Lowe's. Hillman part # 881026 is a brown plastic hinged screw cover, 4 to a pack. One side is rounded, with a flat side with a lip that will exactly fit a 3/8" hole. Take that half, dremel out the center to be 11/32" or so, and use that as your grommet. It's brown, it blends, and it totally disguises the fact that you made a complete hash out of something simple like drilling holes.

 

[Emperoroz]

So all the pieces fit pretty well. I'm still waiting on the recording/playback circuits. Again, this is a fully functional video/audio transmitter. :] The lithium ion batteries (3.5mm thick) shown in the photos should provide about 3 hours of continuous video talk and 8 hours standby time. (thing sucks energy). Transmitting between 2.4ghz and 2.7ghz. Units tested at 80 feet this far but service notes claim 600 meters without obstructions. (my chinese is rusty). Trans/rec assembles are beneath the screen circuit in the photo.

Next I need to design and cut out the channel selector assembly. (the rotary switches available are way too deep to use).

Total cost so far is under 100 for each farnsworth.


Jason

 

[PeterLC]

How well is the transmitter and receiver going to work inside a metal box with no external antenna?

 

[Emperoroz]

How well is the transmitter and receiver going to work inside a metal box with no external antenna?

My bench test was with the transmitter in the box. Seemed to work all right. If I encounter an issue when the whole thing I'd assembled I'll probably add that plug in antenna evil artie used to spy on farnsworth communications.


Jason