I know I’ve seen someone do it on one of these music project forums, but I searched to no avail. I’d like to know how to make a resistor network using 10k, 5% resistors as opppose to the Single In-Line that is usually used at RN1.
I’m having weird issues with the last digital control board. I’m putting pots switches and LEDs off-board. I was able to get it working on my third board, but when I finished soldering and powered this board on, all LEDs were lit and no buttons worked. I thought that maybe I forgot to flash the chip, but this didn’t work. I took the ATMega and put it in another board and it worked fine, so that’s not the problem. I checked both shift registors the same way, and they’re ok.
When I started assembly I noticed a couple of the terminals on the resistor network were broken, so I treated them like SMT components and soldered their nubs to the board. I have resoldered these connections and now only the first LED is lit and the buttons don’t seem to do anything. I have a feeling there’s a bigger issue going on here, but I’d like to rig some extra 10k carbon films just to see if this is the issue. Thanks
I should mention that the 3 working boards are v0.5. This troubled guy is v0.7.
Simple but not elegant. Basically all the holes get one end of a 10k resistor except pin 1. All the other ends of the 10k resistors get bussed together, and that connection goes to pin1. So you should need eight resistors.
Those resistors pull up the voltages at each switch to 5v when the buttons aren’t pressed. The buttons get pulled to gnd when pressed. So you can check each of those at the switch to make sure that’s what’s happening. Next you could check the 74165 and make sure it’s getting power. The button section is relatively independent of the LED section.
However just swapping the chips may not show the underlying problem, which is more likely a bad solder joint on one of the sockets - either of the 165, the 595, or the atmega.
I’m not sure why you say I would need 8 resistors when there are 7 positions and the first connection doesn’t get a resistor.
i’ve done that on a 6582 board and i still have to change it again, it looks awful, really.
but the problem you describe seems something else, especially as you say you wired it all offboard.
check that you have not swapped led wires and/or switch wires, also the pots are easy thing to mistake direction.
i had the same issue but to me it was clear that i must have had wired sth the wrong way, just because i know that it had worked before.
a close look at the board or the brd files tell you the correct placing and orientation.
maybe worth checking before soldering again.
Update: I resoldered all pins connected to the ATMega and switch register sockets as well as the buttons and RN1. I used a multimeter and checked if 74165 was getting power. It’s getting 5V and so is the 595. I checked pin 10 of ATmega’s socket and it registers 5V. I checked the button positions on the board and off board and they were 5V and went to 0V when pressed. Here’s a pic that shows the points I checked. The YELLOW arrows are 5V. The red arrows were 5V and went to 0V when the button they were connected to was pressed.
The problem hasn’t been resolved.
Oh and I hadn’t mentioned it, but the LCD only shows an upper row of blocks. Seems like the ATMega is somehow disconnected perhaps, but I can’t tell where.
oh that’s not like mine behaved, the lcd was all ok.
it sounded the same at first, as i also had the strange led / button behaviour. i’ve brought all frontplate digital grounds with one wire to one of the switches ground pads. when i messed up the orientation it all didn’t work :D, except for the lcd.
Sorry for that stupid question: whats the advantage of makin your own resistor network?
Thats what i was asking all the time myself: A readily one made is 8ct, o resistor is 2,5ct x 8 = 10ct, so you are doing all the work for -2ct
I just don’t have any lying around. It’s not a permanent solution.
Ah, its the Apollo 13 Situation…
Yes, and I live in Houston so it all comes full circle.
Maybe you can steal a resistor network from an Apollo Command Module in the Exhibition?
Weeeeeeeell the resistor network would probably be 20 kg and require a hand crank.
But it would be 0,000001%, space tested and 100% rocket science!
OOOOOOR it could be foil and styrofoam because we didn’t go to the moon. They tell all Houstonians the truth around 3rd grade.