I have been working heavily on iterating the design of the flip display, I have removed nearly all the glued finger joints and replaced them with T-joints using M3 machine screws, nuts and shake-proof washers.
I have also removed the middle wall and replaced it with a small motor plate and M3 x 20mm spacers.
I have also figured out the correct dimensions for the top front lip to allow the characters to stay in the right place until they are pulled down out the way for the next flap.
Finally I have switched to a metal 5mm steel shaft with bearings on either end and MXL timing pulleys for the motor and the spindle.
The MXL timing belt connects the motor to the spindle without a middle wall to support any gears.
M3 x 20mm spacers hold a dramatically smaller motor plate in position, supporting the weight.
To square up the unit and keep it rigid a top and back panel have been added to the housing.
In the distance the pulley is secured to the metal shaft which is connected to the motor via a MXL timing belt. The pulley protrudes from the disc on the far end to reduce the width of the entire assembly.
In the middle a universal mounting hub is connected to the spindle. This buries the hub inside to further reduce the overall width of the spindle.
On both ends the shaft is held in situ by a small (5mm ID x 9mm OD x 3mm W) bearing that is secured with two M3 x 6mm screws and nuts.
The tension of the timing belt helps to prevent the spindle from sliding free and falling out.
No front housing is present but could easily be added.
This side plan view gives a better sense of way things are connected.
Today I got a nice email from Myron with a picture of his assembly, he says that the Arduino Due didn't work out and he has switched to using several Arduino Mega's. Using this mechanism he has been able to control 48 units and they are trying to finish the project before the end of the week and will be sending me another update!
It's a bit shonky, the design needs refinement but thats something I am working on, I put the thing together and realise some things were wrong so I have to make another change, but it's pretty good otherwise, I am stress testing it overnight to see if anything breaks.
This is my new design for the flap holding carriage. The new design is narrower as the mounting hub is inside the unit rather than on either side, this saves a good 5-10mm, additionally because there is one point of mounting to the hub and the two discs either side are held in position by the square spacer unit the holes from one side to the other are exactly perpendicular and stay aligned. The new design is in part inspired by the H-section in the flipbookit.
I have been working a bit over the past few months on the latest version of the split-flap display, I haven't gotten to the making process yet, but I have beeing costing, and it's a lot more expensive than originally thought, perhaps £200 per unit!
I am going to try and build the latest one soon, I want to get the first revision of a dedicated PCB made that has all three parts, the stepper driver, RS485 transceiver and the basic Arduino embedded so I can work on the firmware and test the prototype.
Today I got in touch with Myron Lo, the person involved in building the DIY flip display I wrote about previously, and they are apparently building this as part of a performance with the intention to share the designs later, there is more information on their Indiegogo page where they are seeking $10,000 to put their performance together.
The Indiegogo campaign has some great rewards, I've backed and hope you will also. Keen to see how they solved some of the problems, Myron said they'd read a lot on my website but hadn't had the time to contact me yet.
Very excited, and super keen to start working on this PCB that will have the RS-485 converter, the Arduino board and the stepper driver and sensor sockets on it, this will be the motherboard of each unit and allow them to be daisy chained without the hassle that Myron has had with I2C wires everywhere.
An Electrical Engineer by the name of Myron Lo has recently been working on a very similar project to myself, to manufacture his own flip display project. He is driving Adafruit motor shield using I2C from an Arduino Due rather than using a small MCU on each module, and has successfully manufactured a number of these units. So far he has made 16 and aims to make 64...
I feel rather like I have been beaten to it, but I am aiming to spend some time on it very soon!