Protoboards, Electrical Noise, Ground Planes, ETC...
idbruce
Posts: 6,197
Hello Everyone
This problem is in reference to a current project that I have going to add sound to my machine. Throughout this post, I will be referencing to the attached photos and to reference numerals on the photos. The same reference numerals will be used throughout different photos but will be referring to the same part or location.
To add sound to my machine, I hacked up an old cdrom and dissected an old unused protoboard, and shoved it into a radio shack project box and call it my wave player. Please refer to Photo001 to see new board outline. As you can see from this photo, I removed a large portion of the board, and I am sure a large portion of the ground plane.
Referring now to Photo005, the machine is powered by a homemade power supply box (REF #1) which outputs 50VDC, 24VDC, 12VDC, 7.5VDC, and supplies all these voltages to the control panel (REF #2). The control panel houses two protoboards, eight motor drivers, and lots of circuitry. Considering all the different voltages, all the circuitry, and electrical noise housed in the control panel, the machine actually runs pretty good. However, ocassionally the machine has problems starting and initializing, but once it is going, it goes.
One of the protoboards within the control panel supplies a HIGH to the wave player to start playing a sound file. Please refer now to Photo012, Photo019, and Photo013. The cable (REF #4) which carries the HIGH to wave player (REF #6)(Please note the wave player is not actually in the photos) is bundled together with some motor cables and other signal wires (REF #3).
Before I go into the problem description, there is one other thing you should know. The protoboards housed withing the control panel have ready access to 7.5VDC at the flip of a switch. Upon powering up, a HIGH is sent to a relay which kicks on the power going to the power supply, and then passes that power and voltages to the control panel.
Okay now for the heart of the problem and the facts.
Could it be that wave player is housed under that metal rectangular frame?
Could it be that I removed to much of the ground plane off the protoboard?
EDIT: I wonder if a ground wire from the wave player protoboard to the control panel would help any. While await replies, I will try it.
EDIT: By utilizing a test lead from the wave player to the control panel, I am now capable of receiving an erratic signal within the wave player, as verified by a test LED. I now wonder if a good solid ground will resolve the problem.
This problem is in reference to a current project that I have going to add sound to my machine. Throughout this post, I will be referencing to the attached photos and to reference numerals on the photos. The same reference numerals will be used throughout different photos but will be referring to the same part or location.
To add sound to my machine, I hacked up an old cdrom and dissected an old unused protoboard, and shoved it into a radio shack project box and call it my wave player. Please refer to Photo001 to see new board outline. As you can see from this photo, I removed a large portion of the board, and I am sure a large portion of the ground plane.
Referring now to Photo005, the machine is powered by a homemade power supply box (REF #1) which outputs 50VDC, 24VDC, 12VDC, 7.5VDC, and supplies all these voltages to the control panel (REF #2). The control panel houses two protoboards, eight motor drivers, and lots of circuitry. Considering all the different voltages, all the circuitry, and electrical noise housed in the control panel, the machine actually runs pretty good. However, ocassionally the machine has problems starting and initializing, but once it is going, it goes.
One of the protoboards within the control panel supplies a HIGH to the wave player to start playing a sound file. Please refer now to Photo012, Photo019, and Photo013. The cable (REF #4) which carries the HIGH to wave player (REF #6)(Please note the wave player is not actually in the photos) is bundled together with some motor cables and other signal wires (REF #3).
Before I go into the problem description, there is one other thing you should know. The protoboards housed withing the control panel have ready access to 7.5VDC at the flip of a switch. Upon powering up, a HIGH is sent to a relay which kicks on the power going to the power supply, and then passes that power and voltages to the control panel.
Okay now for the heart of the problem and the facts.
- With the wave player in place and the relay disabled, the wave player works perfectly.
- With the wave player in place and the relay enabled, the wave player fails to work.
- With the relay enabled, the wave player cable (REF #4) is capable of flashing an LED on and off.
- With the relay enabled, and the wave player held two feet from the machine, the wave player works perfectly.
Could it be that wave player is housed under that metal rectangular frame?
Could it be that I removed to much of the ground plane off the protoboard?
EDIT: I wonder if a ground wire from the wave player protoboard to the control panel would help any. While await replies, I will try it.
EDIT: By utilizing a test lead from the wave player to the control panel, I am now capable of receiving an erratic signal within the wave player, as verified by a test LED. I now wonder if a good solid ground will resolve the problem.
730 x 547 - 58K
730 x 547 - 65K
730 x 547 - 58K
730 x 547 - 51K
239 x 170 - 21K
Comments
Of course, no one will ever have the exact same issue that I did, but someone may eventually have a similar problem with signals after chopping up a protoboard. My problem was resolved by installing a good, solid, and hefty ground from the choped up protoboard to my control panel. I now have player where I want it and it works.
Bruce
What is unexpected is to finish soldering components and wires on a new protoboard and discovering a dead short between layers. I don't know if solder leaked passed the thru-hole plating or what, but I found a Vdd jumper wire I had soldered in an adjacent hole right next to the long row of Vss holes. No solder bridges - clean both sides, and that hole was still shorted after lifting the wire, but the board did fortunately power up fine.
I needed the durn hole to connect an SD adapter pin, so I drilled out its plating and stuck the wire with insulation through it. Worked out ok, but lost time although I saved the board. I check my other new boards at that hole as good.
Murphy's hurdles?
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