hi, i have a pinball machine project im working on , & want to keep the 6.3 v globes , can i use the mega board , & will the 5v still light the globes , or is there another board i can use to boost from the mega 5v to 6.3 volts?...thanks -bill
billstats:
hi, i have a pinball machine project im working on , & want to keep the 6.3 v globes , can i use the mega board , & will the 5v still light the globes , or is there another board i can use to boost from the mega 5v to 6.3 volts?...thanks -bill
6.3v - AC or DC? The question arises because 6.3vac was used for the heater voltage on tube equipment back in the day.
A secondary issue is the current consumed. I/O pins are rated 40ma max. How much does a single lamp draw?
...want to keep the 6.3 v globes , can i use the mega board , & will the 5v still light the globes.
Assuming you mean filament lamps (you don't say), try it. 5V will light a 6V3 filament lamp, just not as brightly. However, as dougp suggests, not from an Arduino output at any voltage, the current isn't available.
Probably need MOSFETs on the outputs to drive the lamps, then you can use 6V3 to power them. However, they are possibly being fed from AC, you need to find out. No problem feeding filament lamps from AC or DC, they don't care.
I suggest the one you want is PD7-D7 driving Q3 IRL540.
thanks for your help gents. so could that single irl540 mosfet draw 6.3v from the ac power supply? or would i need an ac - dc converter .i will probably need higher rating mosfets for the 24v solenoids then ? i have the flippers , slingshots ,bumpers running off the ac power supply at the moment .
billstats:
thanks for your help gents. so could that single irl540 mosfet draw 6.3v from the ac power supply? or would i need an ac - dc converter .i will probably need higher rating mosfets for the 24v solenoids then ? i have the flippers , slingshots ,bumpers running off the ac power supply at the moment .
Are you confirming our suspicion that the 6V3 supply is AC?
No, the MOSFETs won't with with AC. You need to:
- Confirm it is AC
- If it is, check if is floating or not (not connected to ground or grounded)
- To use the AC supply you need to connect a bridge rectifier to make it DC, then a big-ish capacitor (maybe 2200μ or something) and a buck converter to 6V or so (if you use a slightly lower voltage the bulbs will last longer)
- Connect the -ve from the converter to the Arduino
Magnetic devices are not so simple; filament lamps don't care about AC or DC. 6V3 AC or 6V3 DC is all the same to them. Anything with a winding has inductance, inductance blocks AC. Whatever voltage they are designed for with AC they will need a lower voltage for DC, you will have to experiment. Maybe measure the AC current, measure the resistance and calculate the DC voltage needed to give the same current as you measured for AC. You also need diodes across any inductive loads to catch the back EMF.
Check the data sheet for the IRL540.
I just thought of something that you will have to experiment with, it might or might not be a problem. If you use MOSFETs to switch the solenoids you have to put diodes across the solenoids to stop the back EMF. If you put a diode across a solenoid it has the effect of slugging it, which means it will release slowly, maybe too slowly, maybe not, you have to experiment to find out.
To control AC solenoids you will requite Triacs combined with MOC3020 opto-isolators.
billstats:
& want to keep the 6.3 v globes
Couldn't you just keep the globes but replace the 6.3V lamps with a white LED?
A warm white LED would be more in keeping. 
What powered/controlled these lights originally? Do you still have the original power supply or anything else? There must have been relays or directly-wired switches, etc. A lot of these machines had relays (instead of solid state electronics) but that would depend on the age/vintage of the machine. (I don't know much about the history of pinball machines but I know the older ones were made before microchips, and some before transistors.)
...The machine may have had a multi-tap transformer supplying 6.3V and 24V.
If you don't have the original power supply, the easiest way to get 6.3V is with a [u]transformer[/u] wired to the incoming AC power.
If you don't have the original relays you can get relays, plus you'll need a driver circuit for the relay coils so you could get a relay board (complete with a driver) if you don't want to make the circuit yourself. Or, you could use a solid state relay (which the Arduino can drive directly without a driver). Just make sure to get a solid state relay designed to switch AC (AC & DC solid state relays are different).
the transformer is ac (240v australian wall socket) but it has the pop bumpers using dc , so what (williams pinball co) did was they used a bridge rectifier for the bumpers specifically & ac for the rest -relays ,lights etc. i will get some photos up to show the set up.
I will get some photos up to show the set up.
That will be fascinating, years and years since I have seen inside one of those machines. Please take some of the whole machine, I'd be interested to see what you are working on 
You will have to work out how things are wired at some point, and decide how much of the original design you are keeping. Is this a complete re-build with modern electronics or is it an electronic enhancement to a restoration of the original design?
It’s got 2 - 6v outlets & 1- 24v for the solenoids,& the bottom of the cabinet is full of relays ,they work of a carousel type score motor that rotates when a target is hit ,then that relay pulls in 100points ,which is calculated .
Thanks for the photos, fascinating
They do make me wonder what role there is for any modern electronics, shouldn't you be aiming to keep the machine as original as possible?
Generally I keep them as original as possible , but I got this pin with a few others 10 years ago,& this one came as only the cab, I have been looking for a matching head for years & decided that I never will find one . I actually have a spare non matching head that I will use for it...
Do u think this bridge rectifier would be ok to use with the buck converter , it came off this machine with the yellow thing .:.capacitor?.. but I think the dc power was used only for the pop bumpers ,where as the rest was powered by ac.
(Got something against using the img /img tags for your photos? Moderator)
The yellow thing is a capacitor, 1μF. Not nearly enough to use with a bridge rectifier, you need maybe 2200μF, more would not harm.
Now I know more than I did when I originally replied I find myself wondering what the best approach is. Do you fundamentally need an Arduino at all? I think I would be aiming for not using one, but this is not my project. If you do need one, then what is it going to be doing? (If you've already made this clear and I skipped over it or forgot, sorry!). I think you need clarity on what you want to keep original and what you want to add with modern electronics, then that will drive your design decisions and the answers to some of your questions. My original answer was predicated on the assumption that you needed to drive filament lamps with FETs using an Arduino. What I am not clear about is why you need an Arduino, and at the moment, in my head at least, the answer is similar to "it's a bypass, you have to build bypasses".
Your thoughts please.
Yes,all The relays etc will remain ,the plan is to start with the globes then solenoids then wire up the switches .i need the Arduino to add the scoring ,control lights,sounds etc. the cab paint ,playfield & internals won’t be touched.
billstats:
Yes,all The relays etc will remain ,the plan is to start with the globes then solenoids then wire up the switches .i need the Arduino to add the scoring ,control lights,sounds etc. the cab paint ,playfield & internals won’t be touched.
OK, that makes sense.
Something I though of that I think you need to consider; With lots of relays and AC and arcing contacts there is a potential problem of a lot of electrical noise being picked up by the wiring to the Arduino, certainly enough to cause erratic and unexpected behaviour, possibly enough to cause damage. My initial thoughts on this are that all wiring that goes to the Arduino must follow a route that is away from any wiring carrying current to solenoids etc, any wiring that is part of the original design, and that inputs and outputs to / from the Arduino might need additional protection.