Home -> Personal -> Laser Tag -> Building -> Test
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After building the 5.XX main board, but before inserting the PIC chip, I attached a battery to the board's power connector. The Miles Tag technical manual lists a number of test points for 7.2V and 5V readings, and all were correct. After that, I waited for quite a while before further testing.
Due to the casing design and the order I built things in, I first powered up the board with no sound card (J5), no serial connection (J6), and without the trigger/reload/mode switches (J1). All other connectors were in place, and a set of sensors was connected to the sensor jack. I figured I could manually short the pins on J1 to simulate using the trigger, reload, or mode switches, and that worked well enough for testing. On power up, the system flashed the hit LEDs on the sensors, and gave a short double beep on the piezo. It then started giving a triple beep at one second interval: bi-bi-bip, pause, bi-bi-bip, pause, bi-bi-bip, and so on. The LCD display also showed a solid "no characters" display, with the backlight on. I removed power and looked at different connections on the board, until I realized I'd managed to somehow reverse the leads on the IR LED connector. I changed the poles from plus to minus and from minus to plus, and reapplied power...the triple beep was gone. I also remembered that I'd neglected to do the backlight modifications for the LCD.
With the IR LED connected properly, I tried shorting the pins on J1 to simulate the trigger, reload, and mode switches. The trigger produced a single short beep, which also caused the muzzle LED to flash. Looks like the firing circuit is doing OK, at least for the muzzle LED. After 20 shots, the trigger produces no noise; time to reload. The reload switch causes a double beep, followed by a short wait, followed by a second double beep, and after that, the trigger once again beeps. Looks like the reload circuit is working too. Hooray, I didn't fry the microprocessor either!
A quick check of the Miles Tag Operation Manual, and I find that the LCD contrast is set too bright. I turn R2 down (at least 10 turns) and I now have a readable LCD display. It's functional!
Some time later, I add the sound board to the system. I hook it up, and turn things on. The piezo buzzer beeps once on startup, and the speaker gives some faint white noise and a quiet "modulation click", similar to what you hear on your handheld radio when someone pushes the talk button on their handheld radio. Pressing the reload button gives a similar modulation click, followed at the appropriate interval by another modulation click. Pressing the trigger gives a modulation click. I've clearly got a problem.
I check all sorts of things: the speaker wires are physically fine, the 6-pin Molex connector is physically fine, the high voltage (+B) wire is connected properly, the components on the board are installed with the correct orientation. I finally realize that I've reversed the pins in the ISD-side Molex connector, so that GND and FF are swapped, +5V and CE are swapped, and PD and EOM are swapped. I correct the connector by pressing the detents with a small screwdriver, slipping the crimp connectors from the housing, and then putting them back in the correct order. The behavior does not change; I still get faint white noise and modulation clicks instead of the expected sounds. I swap in the other ISD board, which was going to be for my second tagger, and everything works as expected. Either I've fried something on the first board, or I've cleared the sounds from the ISD chip. Once I have an ISD programmer/player, I'll pop the chip out and check whether it still has sounds.
Useful for debugging while the LCD isn't working.
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Copyright © 2007, Leif Bennett. All rights reserved.