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Yes I added
Pinball info
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All sorts of Clocks!!
- Thread starter AlanJ
- Start date
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Pretty sure I blew up the relay contacts as I had not added diode originally in my excitement to get it working
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New Mosfet board arrived a couple of days ago. I fixed it in and it's run perfectly for last 36 hours, so I am now happy with what i have got.
part https://www.ebay.co.uk/itm/4-channe...fet-switch-module-for-arduino-9H/224017014979
I then realized a bit of a schoolboy error on wiring up the score reels. i'd wired them with a common ground and separate switchable positive wires - this was fine using relays to switch them, but with the MOSFET's, the switch needs to be on the ground side, with a common +24V. I could have cheated and used the wiring as it was (just reversed the diodes), but having orange ground wires and a black 24v+ wire, just didn't seem right, so I rewired it.
Pic of new board in place
So now the +24v orange is the common wire.
part https://www.ebay.co.uk/itm/4-channe...fet-switch-module-for-arduino-9H/224017014979
I then realized a bit of a schoolboy error on wiring up the score reels. i'd wired them with a common ground and separate switchable positive wires - this was fine using relays to switch them, but with the MOSFET's, the switch needs to be on the ground side, with a common +24V. I could have cheated and used the wiring as it was (just reversed the diodes), but having orange ground wires and a black 24v+ wire, just didn't seem right, so I rewired it.
Pic of new board in place
So now the +24v orange is the common wire.
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Inspired by the above i have got interested in anything electro mechanical, and i discovered a type of 7 segment display called a flip digit display. these are so cool. they make a satisfying click as each segment is set or reset. there is a tiny coil for each segment. so each digit has 7 coils.
because of the complexity of these they are not cheap!
i managed to find a circuit board with 16 of them on it. no prizes for recognising what this came out of![emoji2]
i decoded the circuit board to figure out how each one is wired up. then i realised these are not easy to control. to set a segment you apply a positive voltage around 15-20v. to reset you have to reverse the polarity. that’s not that easy to do in an electronic circuit. i spent a few days trying to figure it out, i did and have ordered all the parts to try it, but.....
then i found on ebay a control board that drives the display board, so i bought it :
it has 16 large transistors. presume this switches the 16 digits on. then it has 2 banks of 7 smaller transistors. 7 to set and 7 to reset each of the 7 segments. if i can figure out how to ‘talk’ to this board i may be in business....... that’s my task for today. there are no circuit diagrams available anywhere on the internet grrrr.
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because of the complexity of these they are not cheap!
i managed to find a circuit board with 16 of them on it. no prizes for recognising what this came out of![emoji2]
i decoded the circuit board to figure out how each one is wired up. then i realised these are not easy to control. to set a segment you apply a positive voltage around 15-20v. to reset you have to reverse the polarity. that’s not that easy to do in an electronic circuit. i spent a few days trying to figure it out, i did and have ordered all the parts to try it, but.....
then i found on ebay a control board that drives the display board, so i bought it :
it has 16 large transistors. presume this switches the 16 digits on. then it has 2 banks of 7 smaller transistors. 7 to set and 7 to reset each of the 7 segments. if i can figure out how to ‘talk’ to this board i may be in business....... that’s my task for today. there are no circuit diagrams available anywhere on the internet grrrr.
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Hmmm, interesting. Great find and idea 
what chips are on that control board? Maybe we can work out from them what the interface needs to be??
Also what’s the starting point for hooking upto it ? a ribbon cable header or something? Might be worth drawing out where the header pins go to on the chips etc as that will also help us work out how it works
what chips are on that control board? Maybe we can work out from them what the interface needs to be??
Also what’s the starting point for hooking upto it ? a ribbon cable header or something? Might be worth drawing out where the header pins go to on the chips etc as that will also help us work out how it works
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Had a look at the control board. It has a CD4515 4-16 bit latch chip - this looks like sets up which digit 0-15 you are going to control. the A-D inputs from this chip go direct to the "input" 40 way ribbon cable, so does the latch clock pin. the 16 outputs go to the 16 power transistors.
The there are two CD4011 - quad 2 input nand gates and also two CD4081 quad two input And gates. these are wired together and one side of each input goes to the input 40 way ribbon cable - so I guess that's for 7 segments, and maybe the 8th is to set or reset as it seems to connect to one of the
other gate inputs on one of the gates.
Then there is a 74LS47 - this is a BCD to 7 segment decoder - traced the wires - again the A-D inputs are straight to the input 40 way header ribbon, and the outputs to the output ribbon cable. There is a single 7 segment led on the display board, so I assume it controls this. looks like there is also an enable to the input ribbon cable for this too.
There are some unmarkd ICs, these are near the white DIL resistor banks, maybe they are diodes or something. For the purposes of trying to figure it out, probably don't need to worry about these.
There are 7 pnp and 7 npn transistors. For the set and reset. Printed on board it says set +35v and reset -35v. I hope it doesn't need that much juice!
I've got 2 power supplies, if I disconnect the negative from the ground I can combine them into a split rail power supply with +30v =0 = -30v. The commons on each bank of transistors lead back to the input ribbon cable. I also found what I think is the +5v wire as this connects to the VCC of each of the ic's.
This is fun, I've never decoded a physical circuit like this before!
The there are two CD4011 - quad 2 input nand gates and also two CD4081 quad two input And gates. these are wired together and one side of each input goes to the input 40 way ribbon cable - so I guess that's for 7 segments, and maybe the 8th is to set or reset as it seems to connect to one of the
other gate inputs on one of the gates.
Then there is a 74LS47 - this is a BCD to 7 segment decoder - traced the wires - again the A-D inputs are straight to the input 40 way header ribbon, and the outputs to the output ribbon cable. There is a single 7 segment led on the display board, so I assume it controls this. looks like there is also an enable to the input ribbon cable for this too.
There are some unmarkd ICs, these are near the white DIL resistor banks, maybe they are diodes or something. For the purposes of trying to figure it out, probably don't need to worry about these.
There are 7 pnp and 7 npn transistors. For the set and reset. Printed on board it says set +35v and reset -35v. I hope it doesn't need that much juice!
I've got 2 power supplies, if I disconnect the negative from the ground I can combine them into a split rail power supply with +30v =0 = -30v. The commons on each bank of transistors lead back to the input ribbon cable. I also found what I think is the +5v wire as this connects to the VCC of each of the ic's.
This is fun, I've never decoded a physical circuit like this before!
Looks like a fairly simple matrix system then to control them. Should be fairly straight forward from a control point of view. The 4 bit binary input for the digit select will save on io pins to
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Decided to build an arduino test rig to see if i can get these EM 7 segments going. so far i’ve got it outputting a 4 bit shift register for the selection of the digit to control (0-15) i’ve used the 5th bit to enable the latch, then i’ve wired up another shift register to handle the 7 segments. the 8th bit i am using to select whether the segments should be enabled or disabled. done a bit of code that selects each digit in turn and fires a number or letter at it. that seems to be working as i have a led on every output and they are working as expected.
now i’ve got to wire all the outputs to the input ide cable on the controller board.
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now i’ve got to wire all the outputs to the input ide cable on the controller board.
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pics of how these creatures work:
7 little coils that magnetise the mechanism and either flip it up or pull it back down to the side.
when you disconnect power the display stays where it was.
amazingly also if you remove the top and then put it back on it sets to the last displayed digit even with no power so it must be retaining the magnetism. i find that really cool
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7 little coils that magnetise the mechanism and either flip it up or pull it back down to the side.
when you disconnect power the display stays where it was.
amazingly also if you remove the top and then put it back on it sets to the last displayed digit even with no power so it must be retaining the magnetism. i find that really cool
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Very impressed with this project, was kind of hoping when I received a new post notification from this thread the EM reel clock may be becoming available to purchase, it's so cool 
Chris.
Chris.
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@taz turbo I have got some more EM score reels, so may be making another !!!
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check his store - they are in stock - you need to select the different types from the drop down as he doesnt have them allI cant find any
I'll ask Andy again as he was going to take a look!
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Spent far too much time on this, ha ha, but looks like a winner. With all these digits I can display other info as well as just the time.
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COMING SOON!!!!
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I’ve got a few more sets of score reels. So I’ll make a very limited number of these clocks for sale.
I’m currently testing and cleaning and degreasing the score reels. got some duff coils in the batch i bought, but still should have enough for a few clocks.
Some are filthy:
But they come up nice with some elbow grease:
I’m currently getting the ones with good coils in working order. Many are jammed up, weak springs etc. so quite a job on for next couple of days......
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=============
I’ve got a few more sets of score reels. So I’ll make a very limited number of these clocks for sale.
I’m currently testing and cleaning and degreasing the score reels. got some duff coils in the batch i bought, but still should have enough for a few clocks.
Some are filthy:
But they come up nice with some elbow grease:
I’m currently getting the ones with good coils in working order. Many are jammed up, weak springs etc. so quite a job on for next couple of days......
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Two whole days cleaning and freeing up years of muck and grunge on score reels.
I made a little wooden jig to hold a score reel so i can work on it.
One of the most tricky bits is getting the “zero” switch setup and working properly.
I’ve figured it’s quickest to get a reel in the jig, desolder the old wires and then solder on all the wires we need fro the clock, then test and adjust the zero position switch and test it a lot of times!
Once I’d done all 4 I wired them together and to the electronics.
below is a working clock all wired up and currently in test for a good day or so.
I’ve received a nice metal faceplate today from [mention]taz turbo [/mention] (many thanks) so next job is finish the wooden case and install this clock.
In the meantime I’m on with more electronics - building up a couple more units.
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I made a little wooden jig to hold a score reel so i can work on it.
One of the most tricky bits is getting the “zero” switch setup and working properly.
I’ve figured it’s quickest to get a reel in the jig, desolder the old wires and then solder on all the wires we need fro the clock, then test and adjust the zero position switch and test it a lot of times!
Once I’d done all 4 I wired them together and to the electronics.
below is a working clock all wired up and currently in test for a good day or so.
I’ve received a nice metal faceplate today from [mention]taz turbo [/mention] (many thanks) so next job is finish the wooden case and install this clock.
In the meantime I’m on with more electronics - building up a couple more units.
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Here is the faceplate, it’s showing the dull reverse side, the proper side is a nice mirror finish, thanks again Chris [mention]taz turbo [/mention]
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Pleased you like it Alan, looking forward to seeing the finished clock, and the mirror finish.
Wish I could get my head around this programming malarkey. I decided in my spare time during lockdown to learn some PCB design software, I failed terribly, but silver cloud is Jim at myPinballs offered his services, so kind of a result I guess
Keep up the great work
Chris.
Not sure why this hadn't popped up on my feed, or any of the previous posts either (just read back to the start of the month!) really cool stuff going on mate that control board debugging was next level. Amazing to see the results too, that must have been a buzz seeing them flip over for the first time.
Is the idea two different clocks, one with the 7 segments and one with the reels, or are you planning to combine?
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Two different projects. the em score reels are ‘easy’ compared to those 7 segment em displays. they are so hard to control
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but never say never.......
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Amazing work those mechanical 7 segment displays are SO satisfying. They remind me of the old clocks at trainstations that always had broken segments.
Those decagon units are awful, I spent hours and hours adjusting the 9-0 switches on my Roadrace project and could never get it to reliably know what was going on. Will be giving myself another headache with them soon. A lovely project though and a great idea
Those decagon units are awful, I spent hours and hours adjusting the 9-0 switches on my Roadrace project and could never get it to reliably know what was going on. Will be giving myself another headache with them soon. A lovely project though and a great idea
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I've made one for sale, possibly more, see this thread: https://www.pinballinfo.com/communi...-clock-gauging-interest-initially-£250.46567/
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I've been playing around with one of my EM's to see what is involved in achieving this. In theory it seems easy, but in practice it's turning out to be pretty tough, but not impossible.
I've got the 4 score reels being controlled in-situ by the controller and 24v DC power supply from the 'clock'. This works fine when the machine is switched off. It's not good when the machine is switched on as we could potentially have 25v A/C and 24V DC from separate power sources on the same line... Not good. So I put in a relay, and then hooked up a feed from the pinball to detect when the power is on in the pinball machine. This needs an opto-isolator to convert a simple feed from either the 6v or 25v rail into a signal I can use. I modified the software to switch an opto isolated relay and disengage the 24v DC power to the reels as soon as the power to the pinball is switched on. So far so good.
I then realized that I can then no longer control the reels as the pinball is using 25v AC and I'm using DC only mosfet circuits to move the reels. I could go back to using opto isolated relays to solve this problem, but the crappy relays from china are not up to the job, I could beef these up by adding a better relay that can handle the current. The other option and the one I went for initially was to tap off a DC supply from the 24V ac using a bridge rectifier - a bit crude but it works (could do with more on here like some smoothing caps etc). I then realised it's not that easy to separate out the wires and feed to the 4 score reels from the A/C feed to make them DC. So back to square 1 - it is going to be easier to just control with A/C - so back to the relay idea. I've found some 12v 100A automotive relays, not ideal as I've got 24/25 or 6v. But I'll figure out a way.
Then I went on to figure out how to tell where the reels are - the way the EM clock works, is it initially zeroieses each reel - checks the zero position switch then keeps a count. So, I used 4 way opto isolator to try measure the 4 switches, one on each score reel. This is tricky as the switches are wired in series to each other, so I have to figure out where to connect the power in and signals out wires, needed to study the schematic, quite a bit of messing about here. Also to throw a spanner in the works there is a 'hold' relay that also connects across the 10's unit zero position switch. That might be a problem! I may have to stick in a diode to kill that for my purposes but still allow it to function for the game itself.
Im not onto the game oveer relay, again I need to get a signal off that relay to figure out if we are in a game or not! Not sure if the game over is the right one, or maybe on of the other relays would be better. Still studying. Again this will need an opto isolator.
So, so far I have got:
1 24v PSV
1 Esp32s controller & 5v psu step down board.
1 Real time clock module.
6 Opto isolator input circuits - 4 for the score reels zero position, one for pinball power and 1 for game over
5 output opto isolated relay circuits. One to switch on/off the DC power. 4 for the score reels to go via beefy additional relays.
a ton of wires into and out of the pinball machine.
It's starting to look rather unwieldy! Might have a sit back and see if there is another way.............
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Spent another few days on the above. Decided to abandon it, it's just too much messing about with the original wiring of the pinball to make it feasible. I was even thinking of installing a camera system to 'read' the score reels values, this will make it a lot less intrusive.
Back to the 7 segment 'flip' display project. I've managed to source some pretty obsolete driver chips for these, that help solve the problem of having to reverse the polarity of the supply voltage to set and reset them.
Back to the 7 segment 'flip' display project. I've managed to source some pretty obsolete driver chips for these, that help solve the problem of having to reverse the polarity of the supply voltage to set and reset them.
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Been working on the 7 segment EM displays. built a clock using the original boards.
it can display various time options. hhmm, hh-mm, hhmmss, then a whole set of silly animations. the real pleasure is the lovely clicking noise as the segments physically move in and out.
will post a video link in a mo
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it can display various time options. hhmm, hh-mm, hhmmss, then a whole set of silly animations. the real pleasure is the lovely clicking noise as the segments physically move in and out.
will post a video link in a mo
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latest clock circuitry using 4 of the flip digit electromechanical displays coming along nicely. 2 boards: one with the displays and diodes, the other with the esp32s processor, real time clock and the driver chips.
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