This page will showcase the process and development stages towards my final project.
Presentation Slide
The slide was created in canva . The render of the model was done in fusion 360. I wanted the look of the slide to have the the aesthetics of retro 8/16 bit game font and styles.
Many nice graphic elements were available in the canva library such as the iconography and speech bubbles of games.
Presentation Video
This is a rough teaser video to act as the placeholder until the final video is done. Again here too, i wanted the retro/arcade game aethic to be present throughout. i am still trying to figure out the structure of the entire video.
The video was edited in can . Under the video category in canva there were many motion graphic templates available under the retro game category. I mixed and stitched various elements to create this video. An animation of the cad model was inserted as the intro clip along with the title. I had a video demo of my macropad PCB which was seen at the end.
You can visit my system integration page to get an overview of the processes i am going to follow.
Spiral 1
To make the master module and one node module and make them communicate.
Mockup Stages
PCB Production.
I started the electronics production of the project with the node module.
Components in a node module are:
ATTINY 1614
9 x Mx switches
9 x Diode
9 x Diode
Neopixel pads
2x03 Vertical Pinheader
I had some doubts regarding the placement of the neopixel pads as they had to be wrapped around the pcb and the
solder part sould sit perfectly on the pads.Since the the pcb iam making is quite large , i did not want to waste
an entire copperplate incase something goes wrong. So i thought of making a mockup of the PCB on cardboard see if
everythng aligns well
I kept the pixels in place and found some misalignments.Thet were later corrected in the kicad editor.
pcb for the connectors
I milled out the PCB and moved on to the pick and place machine to place the parts.
CAD Model
I took some time to properly design the housing and how the elctronics would be positioned within the case.
Making Pogo connectors.
I had to think of ways to make the pogo connectors as they are quite expensive and to buy as many as i required may
not be feasible within the scope of this project.
I referred to some videos to make the connectors and went through some design iterations . I made a few mock pieces
to test if it would work properly.
Mockup 1
The first idea was to make a PCB tht would have pin header connection from the top of the keypad PCB , on which
the Pogo connectors mounted on another smaller PCB will be attached perpendicular it.
First to test the concept i tried making a small scale mockup to check the attachments. Two PCBs were made with
just the pads for the connections and the slot for attaching them.
There were some issues faced while milling the PCB due to its small size and since the PCB is double sided. When
the PCB had to be flipped for tracing and cutting the other side , it would fly off because it wouldn't stick
properly. I spent some time trying to make the cut ,so i thought of other ways the PCB could be produced
efficiently. My instructor suggested to use the milling machine to just cut the PCB and then take it to xtool to
engrave it. To keep the PCB in place a cardboard jig had to be made. Even this method did not seem as effective as
it looked on paper. The fit was was checked for the two PCBs and some adjustments had to be made
Also while making the CAD model for the module , it was noted that the size required for the PCB would be
quite large for a double sided PCB (our lab has a limitation on the size for double sided pcbs). So we went back
to
the board to test another method.
Mockup 2
This was initially the plan we were supposed to go ahead with ,but after some thinking and updations we made a
few alterations to it.
Basically the idea is to make the small PCBs to attach the pogo pins and the take connections from this PCB to
the PCB with the connection from the keypad PCB via wires. Tecnically its the same concept as before but we can
make the central PCB smaller and save space.
While making the CAD model i realised a housing had to be given for the pogo pins. The CAD model has to be
altered to make space for the housing too.So that was also done parallel to this process.
For this mockup I just had to make the small PCBs and make sure it fits with it mock 3d prints made. I had made
a careless mistake on the 3d model where the housing had to sit, even though I made it correctly on CAD i exported
the wrong version.
After reprinting the case the PCB with housing was tested and it was fitting perfectly.
Once the fit was checked I moved on to solder the pins on to the PCB along with the housing.
The fit was checked again and I also kept another PCB to act as the landing pad for the pins
Checking magnetism
I checked the wall minimum wall thickness required for the nodes to stick to each other
Locking
Keyboard Disassembly
Button iterations
Week2
Week2
PCB production
After milling out the PCB and placing the components , while trying to measure the length of the led strip to be cut, i realised that the switches and the LEDs did not match . There was a misalignment of one row of switches that affects the whole placement.
So i had to go back into the kicad editor and then realign all the switches . This time to make sure the measurements were correct I edited the snap to grid number to the measurement i required from the centre of one switch to another.
The pad position were corrected as well. I had forgotten to add a capacitor in the previous circuit so i could add that here now.
The PCB was filled out again and the neopixel
Strip length was checked. After confirming everything was alright i moved on to solder the components on to the PCB.
Next the led strips had to be fixed . I first cut the strip to the length of the pad. One led would have to be removed because it won't be visible as it will be on the flip side of the board.
Then I stuck kepton tape on the edges of the traces to avoid any interaction between the copper cladding and the wires within the strip.
I stuck double sided tape on the outer edges of the switches and stuck the strip on to it. Then I soldered the strip to the PCB.
This was repeated for all the rows.
A connection had to be established between the din dout pads of the led that were removed. A copper wire was soldered to make this connection.
After the soldering, i tried to program the PCB to check if everything was working correctly. I uploaded the buttoncycler example code to do a colour change when a switch was pressed. Everything looked good so far:)
Bottom PCB
I had to make a PCB that would sit underneath the module PCB to make connections or the pogo connector PCBs i had made earlier. This PCB would actually as a connection point for the wires to be soldered on . A pinsocket will be given on the side of the PCB that will face the bottom of the body of the module. This is given to make the access to updi programming easier.
Amockup of the mouts were made to check if the connections sat correctly on the body.
Molding and casting the button
I used the similar method for casting the buttons as i did during the molding and casting week. The only difference being that the mold was directly 3d printed as a buttin and the silicon was cast over it. The button was then flipped to get the other side as well. I 3d printed the button and smoothened the layerss by sanding it throughly.It is then casted with epoxy resin. The finish and colour cme out pretty good. The resin did not reach everysurface so i am trying to achieve a proper finish now.
I had to think of ways to make the pogo connectors as they are quite expensive and to buy as many as i required may
not be feasible within the scope of this project.
I referred to some videos to make the connectors and went through some design iterations . I made a few mock pieces
to test if it would work properly.
Next the led strips had to be fixed . I first cut the strip to the length of the pad. One led would have to be removed because it won't be visible as it will be on the flip side of the board.
