Timeline for Problem with acceleration sensor
Current License: CC BY-SA 3.0
16 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jul 5, 2015 at 16:55 | vote | accept | solid | ||
| Jul 3, 2015 at 21:56 | comment | added | Chuck♦ | Okay, edited down to what we've discussed in the comments, with a caution that the chip operates at a lower voltage than the board accepts as an input. | |
| Jul 3, 2015 at 21:55 | history | edited | Chuck♦ | CC BY-SA 3.0 |
deleted 398 characters in body
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| Jul 3, 2015 at 18:19 | comment | added | Chuck♦ | Well, don't know what to tell you. Maybe the chips were dropped, the package was thrown, I don't know, but the self test failed. If all the voltages are correct then I would suspect physical damage. Data sheet for the chip says it can only handle about a 1.5 meter fall onto a hard surface. I would try to return them as DOA. | |
| Jul 3, 2015 at 17:54 | comment | added | solid | neither upullup is connected or J1 is bridged. I am using the SPI4 connection not the I2C. Connecting upullup would invert the logic. | |
| Jul 3, 2015 at 14:28 | comment | added | Chuck♦ | What do you have U pull-up connected to? Is J1 bridged or not? As I read it, Upullup should be connected to what Vhigh is for your arduino, but if J1 is bridged and you have Upullup connected then you have bridged Vhigh to Vin on the chip and you can fry it. If you don't have Upullup connected then you may not be getting signals at the appropriate levels to register clear high/low correctly. | |
| Jul 3, 2015 at 11:55 | comment | added | solid | Here is a link to the German documentary. On page 4 the schematic of the board is shown. | |
| Jul 3, 2015 at 10:43 | comment | added | Chuck♦ | I can't find a schematic of the board, so I'm not sure what to say regarding what to check next. I looked like to me from the website that the input voltage is selectable, as it advertised 3, 3v3, and 5v inputs where it advertised a range on the level shifters. All I know to say without more documentation is that the self test failed, and, level shifter or no, you're giving 5V to the board. Even a startup transient could fry the chips, but again, I can't find part numbers or data sheets for the components on the board. Self test failed on the ones that were suspect; they are definitely dead. | |
| Jul 3, 2015 at 8:53 | comment | added | solid | The circuit provides level shifter for the digital input in a range of 2.5V to 6V. The SDO signal is about 2V (measured with an oscilloscope). All devices show this value, the working one and the maybe broken ones. | |
| Jul 2, 2015 at 18:52 | comment | added | Chuck♦ | Can you probe Vin on the BMA020 boards? What voltage is present on the Arduino side on your signal pins when they're high? | |
| Jul 2, 2015 at 14:27 | comment | added | solid | I disagree, the operating voltage for the chip is 2.0 to 3.6V, this is correct. I use the linked above circuit (shown on the German web page I couldn’t find an English one with this product) which has the BMA020 built in. The circuit provides a linear regulator to supply the BMA020 with round about 3V. The input at the UIN – pin of the circuit is specified with 2.5V to 6V. | |
| Jul 2, 2015 at 14:15 | history | edited | Chuck♦ | CC BY-SA 3.0 |
Found the problem!
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| Jul 2, 2015 at 14:10 | comment | added | Chuck♦ | ACTUALLY I found your problem. See my edit above. | |
| Jul 2, 2015 at 14:10 | comment | added | Chuck♦ | Note that the instructions for the self test say that you can't move the sensor while you're running the self test, but yes, if the self-test passes on the one that reads as expected and fails on the ones that don't, then I would say that they are broken. | |
| Jul 2, 2015 at 13:55 | comment | added | solid | I left the register 14h untouched, but I read them out they are all the same. Like you said I performed the self_test_0 on every single device. They all failed beside the single sensor that delivers plausible data. What does a negative self-test means? Are my 4 out of 5 sensors broken? | |
| Jul 2, 2015 at 12:39 | history | answered | Chuck♦ | CC BY-SA 3.0 |