We are experiencing some problem with the analog infrared sensor.
When we just feed the sensor with voltage and ground, the AVR programmer dies (stops flashing) and the infrared sensor makes this low frequency noise. We are assuming this is probably because of short-circuit or some sort. But how is that possible when there is only one-way that 3-pin female head can fit on to the infrared sensor, and the red wire (which we are assuming to be voltage) is connected to VCC and black wire is connected to GND? I guess only explanation is red wire does not necessarily represent voltage and same for black? Did anyone find a solution for this?
Any reply will be appreciated
We tried with 9V battery attached to the voltage regulator which steps down the voltage to 5V in the circuit. We measured the voltage before attaching the analog sensor and it gave values like 4.96 which is correct. After attaching the analog sensor, the voltage we measured across VCC and GND of breadboard was 3.7. The voltage measured by programmer according to configuration utility was 2700mV which is horribly low. Any suggestions?
Are you sure you connected your 5V regulator correctly? When you have your regulator flat on the desk with the words facing up, your Vin pin is the leftmost pin, your ground is the middle pin, and the 5Vout pin is the rightmost pin.
Checked that at least 15 times with each teammates. Also tried with another VREG with same model, still same problem. There was one team that apparently had same problem when adding analog sensor, and solved it using transistor and capacitors? Anybody know how this would work?
Nothing should cause it to drop that low. Maybe your battery is dead? What's the voltage on the battery? Should be >= 9V.
There are power supplies in the lab if you want to try those instead.
Another cause would be something on the circuit drawing too much current. Do you have an LED with no resistor in series or something? Strip the circuit board of everything but the fewest possible components.
Cheers,
Rehman
Each of batteries we tested were in between 8~9V. Which I don't think is problem because we get exactly 5V when we test voltage regulator circuit (without ATMEGA8)
We dont have LED with no resistor (that wouldve been so bright that we wouldve known whats wrong anyways :( ), we tried starting from barebones and voltage regulator DOES work with just itself (gives exactly 5.00V). But when you put in the ATMEGA8 with bare minimum wiring (VCC, GND, Clocks, Programmer stuffs), the VCC line drops to ~3V sometimes even to ~0.5V. So we tried with another ATMEGA8 and it still DOES NOT work.
P.S. Now it doesn't even work without analog sensor attached. Sometimes it DOES work with all the components (except analog sensor) on board, and gives exactly 5.00V on VCC line.
P.S.2. We double-checked wiring everytime we tried something out with electrical tutorial. Is it possible that electrical tutorial might have incorrect information? Did UTRA execs make their sumo robot based on the tutorial?
Yes, that circuit has been tested by UTRA. It's possible that your 9V battery is dead - it would actually explain your symptoms -- provides 5V with no load, but voltage drops when load added. You can test this by using a different load besides the uC. Maybe a bunch of resistors in parallel? You can also borrow a power supply from the UTRA lab ($20 deposit) to test your circuits.
Rehman
Red is definitely 5V, and Black is definitely GND. It sounds like you may be drawing too much currect from your programmer. USB ports are rated at 0.5A, and drawing more than this can hurt the motherboard on your computer! So I suggest an external 5V power supply. There are computer power supplies in the lab (EA-106) that you can borrow with a deposit, that supply 5V-DC.
Cheers,
Rehman