Mike's Project Tracker

In my initial solenoid power board design, I used a PWM signal to control the power to the solenoids.  I used an AND gate so that the PWM signal could be constantly running but require the microcontroller's command to turn on.  This is done by putting the other pin on the AND gate to HIGH.  I have added a PWM component to the single pulse generator so that I am able to control the average voltage of the pulse. I am also trying to offload as much work as possible off the microcontroller so that it runs quickly.  For most of the solenoids in the pinball machine, the power that is required will not change during the game.  The only ones that I can think would possible change would be the pop bumpers.  I would like them to be stronger during certain periods of play.  To do this, I think I will need to use a 50V power supply in order to be able to play the game at a lower power level and then to have enough reserve to raise it to a noticeable difference....

While testing out my new test playfield with just the mechanical switches, one of pop bumpers got stuck.  As the pop bumper was stuck, the switch remained closed, and this kept the solenoid powered.  The switch generated a lot of heat melting the pendulum from the pop bumper skirt until it melted.  As it melted it became short enough it could not trigger the switch anymore and finally released.  This is not good.  This is a bit of a safety issue.  What happens when you are playing the game and you do not notice. To solve this problem, I determined I needed a single pulse that would not fire again until the switch had been pressed again.  So even if the switch is held down, the pulse is sent only once.  The lower logic level voltage (5V) will not heat up the switch as it will be current limited by a resistor rather than just the solenoid on 35V. To produce this single pulse I used the following: 74AC08 - AND Gate 74HC14 - Hex Inverting Schm...

All the playfield machinery I have I purchased used online or from online classifieds.  Some components are direly expensive such as the ball trough.  So I decided to try and make one. Makeshift Ball Trough / Ugliest Sheet Metal Work Ever Above is a photo of the ball trough I made.  It is ugly, poor workmanship on the sheet metal and the ball launcher is a little loose; but it works.  I purchased a very cheap sheet metal hand brake to make this and other brackets.  I also made a slingshot mechanism as well. Makeshift Slingshot Mechanism It works.  The only issue with the slingshot mechanism is that I had to thread some 1/4 inch rod.  I used two nuts to lock the far side so that it does loosen during use.  The two nuts take up a lot of space a leave little room for the two microswitches that will detect when a pinball has hit the slingshot.  These are a real pain to make when, honestly, I do not have the right tools for it. ...

What we have here is playfield built wrong.  It is not because it lacks parts, or does not have all the features you want it to have.  It is wrong because it is too thick!  My research has led me astray.  I used your standard 3/4 inch plywood to build the cabinet including my prototype / test playfield.  After I put those pop bumpers on and they did not work consistently, I investigated. Bad Playfield!  The playfield is too thick for pinball components. The pop bumpers under the playfield. The photo above shows the three pop bumpers under the playfield.  The pop bumper is triggered when the pinball hits the pop bumper skirt.  The skirt has a pendulum that sticks down below the playfield and can be moved from its centre resting point to a point on the circumfrence of a circle.  The circle's size depends on the angle that the pendulum is actuated to.  There is a leaf switch with a saucer.  Then the pendulum swings out, t...

I also have some more new toys. I was frustrated with my old El Cheapo soldering iron. The tip was too large, the temperature was not regulated and the tip would just disintergrate through normal use. So I bought a nice 60W American Hakko soldering station. My American Hakko 936 60W Soldering Iron What a world of difference. When buying a soldering iron look for ones with ceramic heaters and that have interchangable tips that have the heater inserted. The difference between spending $30 bucks on a soldering iron to one for $70 (Like this one was, on sale) is well worth the price jump.  If you are even thinking of building electronics, do not both with the cheap ones.  Its just not worth it, buy something like this life saver of a soldering station! Makita Li-Ion Drill / Driver  Another tool that I purchased is a lifesaver as well but it is not a necessity like the soldering station.  I purchased a Makita 18V Li-Ion drill.  It was my birth...

I was getting to the point where I really needed to build on something. I have numerous pinball parts but have nothing to attach them to. I managed to find some pinball plans for a Williams Widebody pinball machine. All the measurements are in mm sadly even though all pinball cabinets are in inches. I converted and change it all to the nearest quarter inch. Well sort of. The guy who measured this was intending on using 45 deg cuts in the corners. My skill saw is too cheap for that so I changed the measurements for butted joints. The interior is set for a 23.5" wide playfield. The length of the cabinet is 51.5" in total. I used 3/4 inch plywood so the bottom would be 50" long for example. You can pretty much dimension the rest from there.  I did get a little chipping of the plywood but I went out and bought a blade with more teeth for finer cuts. It's a 60 tooth saw blade and my skill saw doesn't really have enough power for it so I have...

If you are sick of them at this point, you know how I feel.  I was missing a switch.  That's just shocking.  The only way to turn it off was to unplug it. I had no indicator lights as well.  Guess I was not thinking much about safety when I built it.  Another problem with my power supply was I was using old oil and paper capacitors. They work and I still have them but they take up a lot of space, are not as reliable, and on the whole, my power supply was rather ugly. The new sexy version of my solenoid power supply! Out with the old and in with the new. This is my rebuilt power supply. I grabbed a scrap piece of aluminium from work and got a 90 deg angle put in it. The aluminium will act as a heatsink and also minimize electromagnetic waves emitted by the power supply though this is small because I'm using a toroidal transformer when compared to a conventional transformer. I plan on using some chicken wire I happen to have to make a farada...