Projector Lift
A photograph sometimes allows a painter to capture the action of a subject, such as a dancer, and then take all the time needed to put the subject on canvas. Printed photos do not always allow the artist to see small details, however, projecting the image makes those details easier to see. The projector often needs to raised and lowered when working with various size images and in order to minimize "keystone."

This is my "high tech solution to a low tech problem."




The lift uses heavy-duty drawer slides as guides and a linear actuator with 20" travel. The linear actuator came with a corded remote control.

I saw a photo of another table by Charles Limbert, dating from the early 1900's. Construction is a bit less challenging than the previous table. But the lines are great, with interesting negative space. The photo is of a test fitting of the pieces, not yet glued.

Table finished. Mission gel stain with 2 coats of shellac, 5 coats of wipe-on varnish.

I had planned to fume the table with ammonia, but didn't like the results: too gray. Maybe it was particular to that batch of white oak. I'll try again with another project since I now have the fume tent and a gallon of ammonia.

This is a Limbert copy table from plans in a recent issue of Wood Magazine. Wood is quartersawn White Oak. It is almost ready for fuming with Ammonia.
I plan to fume the wood before gluing to make sure as much of the wood is exposed as possible.



The fuming tent is made from 1x2s with 6mil plastic sheet. A clear plastic sheet will be used for the front "door" to be able to see the progress of the ammonia coloration.
I found a good source of ammonia in New Jersey, just south of Camden: WD Service, 780 Creek Road, Bellmawr, NJ (856-931-6100). They will ship UPS. Of course a mask with ammonia filters, goggles and gloves are required for the fuming process.

Some Furniture Projects

Music Stand
Quartersawn White Oak. Adjustment knobs yet to be made.















Tea Table
White Oak with turned leg ends glued and wedged through top.











Arts and Crafts Table
White Oak with mortise and tenon joins.

Finally got some of the electronics and mechanisms to work together.


Watch movie to see work in progress...

Some of the essentials are now working together. The bill sensor, time delay, and trigger for the fast/slow mechanism are functional. The gearhead motor is designed for 24V but goes much too fast at that voltage, even with the 3:1 belt-drive reduction. I am running it on 5V, so I had to build a separate power supply for it.

I mocked up a fast/slow moving arm mechanism in the hopes that it will be useful in a rough idea for grabbing the bill as it comes out of the dollar bill acceptor and whipping it across to some sort of storage.

I found some plastic timing gears (with brass inserts and set screws) and toothed belts from Stock Drive Products (https://sdp-si.com/eStore/) which made it easy to drive the 10" wheel.








But the problem now is that the arm must return to the same spot each time it cycles and ideally it should only cycle once.

Since the idea is to have something interesting in the way of mechanical movement and flashing lights, a second circuit to drive these events is needed.

The 555 timer at the bottom of the board is a one-shot timer, taking its input from the second pole of the Double Pole Double Throw (DPDT) relay on the left. It controls the second relay which will eventually control the interesting (I hope) stuff that will happen.

Once the breadboard sensor circuit worked I used a protoboard to create a usable circuit. The relay will be used to switch 15VDC for the bill acceptor motor.

Bought a used dollar bill acceptor on ebay. The existing electronics incorporated a microprocessor to drive the two motors, one to pull in the bill and the other to push the bill out into a stacking box. I disassembled the acceptor and just used the roller mechanism that pulled in the bill. Since the existing sensor circuits were designed to determine that a valid dollar bill had been used, they were too complex for the simple task I had of accepting any old bill someone wanted to donate. Of course it wouldn't discriminate between money and any old piece of paper.

I used a circuit from a site devoted to model railroad electronics (http://home.cogeco.ca/~rpaisley4/PhotoDetectors.html) using an LM393 dual comparator. One comparator is used with a phototransistor to detect dark and the other is used as a delay. Since the sensor I used was located in the input side, I needed the delay to keep the motor running to pull the bill all the way through. A little experimentation with resistor and capacitor values in the delay circuit was needed.

The Idea

Create a donation box that will encourage visitors to the arts center to make a contribution. Something with lights and action when greenbacks are inserted into a slot. The goal is to make it so facinating that people would keep feeding money so they could see what happens.

It would be fun if a vending machine "bill acceptor" could be used. That could trigger the mechanical action.