List of add ons which the truck will work fine without: blowers, grate shaker, heat exchanger, grate temp, hopper temp, vacuum readings, oh and gasoline. 
In your list above, you saved the best for last!
These are the buttons I got, for $2 each.
Have not ordered a dog ball yet. Still thinking about my options on that one - I may try to apply some silicone to the tennis ball, like Carl did.
I will bring the plastic welder to Argos and let folks try it out, it’s a simple tool and fun to use.
Blower circuit finished. This is rev 3 (or 4?), it took some head scratching but I think this is much cleaner than what I started with. This board will handle four toggles (three blower circuits and a hopper alarm). This took about two days to build because I’m very slow and inept with soldering. But I think it came out well enough in the end.
Finally on to some bigger wires!
1 Like
looks tidy Chris
It looks like a good clean layout.
Switches on the left and loads on the right?
Well done.
Thanks guys. Henry it’s center-rotated, if that makes sense. Power is right center, the rest is alternating relays and switches.
Chris, What’s the DC current rating of the contacts on your relays ?? I seem to recall measuring 3 or 4 amps on each bilge blower so 20 amps should be good for 3. Be careful about wiring contacts in parallel. They do not all hit in the same microsecond so the first one to close draws all the current and may weld shut. I encountered this the first time when our Village fire siren locked in and I had to head to the fire department and neuter it. The fella that built the control panel had several sets of contacts in parallel to handle the current. I use 40 amp automotive relays usually on my projects. There are usually several in the fuse panels and on the firewalls of most junk cars and they don’t cost much new. I just wanted to comment because the sockets you have there look like they are for 4 amp contacts. Of course maybe you have the contacts running to individual motors and not 3 in parallel. I only have one blower and I use a 49 cent light switch to turn it on. After all this ramble, I’m probably looking at IC chip sockets (and I think I see chips in them) but I figured I’d ramble anyway. Make sure you put backfeed diodes across the relay coils to prevent a kick back to your chips… See you in 2 weeks … Mike
Thanks for the advice Mike, I almost forgot the flyback diodes… whoops! No harm done though, I’ve added them. Yes those are 14 pin DIP sockets. I have 40 amp relays for the blower circuits, not shown.
10-4 … Some relays come with them built in but it’s real easy to add them to the output circuits. Silicon diodes are dirt cheap. We used to joke that they are cheaper than fuses but when they fail they short . I’m used to using 1 amp 1000 PIV diodes and have 10 to 20 in a string in each leg of a bridge rectifier to make 4000 volts for my amplifiers. Every once in a while a mouse will run across while the supply is turned on and kerzap … Then I have to solder 4 more strings together. I buy them by the hundred usually from Mouser … If the relay already has one, hopefully it is external so you can see it and not wire the coil backwards … Put a fuse on your board. I don’t see one … It’s usually voltage that kills IC chips rather than current so they can be shorted for a few seconds till the fuse wire melts. I don’t know what the relay coils draw but you would have to fuse for that. I have some brand new 40 amp ones within a few feet of me but they are buried. I will try to measure the resistance of one coil over the weekend to let you know current requirement but maybe Mouser can supply that info … Their catalogs were too thick and I had to send them down the pike. They didn’t burn well in the hopper … Mike
Here’s one advantage to using relays for switching. This is my entire bed switch wiring: a single CAT3 phone wire. A second wire will connect up the cab switches.
Since these switches give a momentary “blip” signal, there’s no need for anything heavier. Gobs of wire eliminated!
The blower themselves will each get a dedicated 16ga power and ground wire. No splicing needed.
Hi Chris, I measured 31 ohms on the coil on one of the relays I had on hand. I will check others as I find them … 14V/31ohms is around a half amp per relay. I don’t know how many relays you plan to have keyed up at the same time or what your chips are rated at … I’m sure there is a bit of surge current to saturate the core … Fuse can be small like 2 or 3 amps ??? … Mike
Mikes right about the freewheel diodes, I’d place them on the pcb, polarity oriented to match the transistors you used - most likely npn’s? That way there’s no possibility of forgetting them.
The transistors should drive an automotive relay without any issues, most run under 200ma once energized. I would probably start with a 1A glass fuse on the PCB and step up to 1.5 or 2 if necessary, though I doubt it will be.
The simplified wiring is but one of many benefits to a more elegant control interface, you’re headed in the right direction for sure.
1 Like
Well, some good progress to report. After my Friday night blues (blew a transistor and 4 ICs by reverse polarity… oops) I finally have the circuitry installed and working. In addition I’ve added a gauge panel, a hopper alarm, LED indicator lights, blower disconnects, an overcenter lever for opening the ball valve, coated my tennis ball with right stuff, and routed my rails vacuum gauge into the cab.
Whew! Taking the rest of the night off… video coming shortly.
Thank God I just have ONE mixing valve, ONE vacuum gauge, and ONE thermocouple … I don’t text while driving and I certainly don’t want to text while driving if you catch my drift … It is tough to hit the switch on my meter to see what the cyclone temp is. I have to take my good eye off the road … :o) … M
Very nicely done!
I wanna see some video of it flaring… Surprise surprise eh.
Gilmore’s over center latch is just the ticket.
That’s one purdy truck ya got there mister
TerryL
Video as promised:
Very nice Chris
Now it just needs to pass you a cold one at the end of the day !
Thanks Patrick
Nice job, is that your new plastic hay filter we see in the video? Did you paint it black?
Now I know I will hide my ole truck behind a building at Argos .
Nice job Chris !!!