Search found 254 matches

by sebmadgwick
Tue Apr 09, 2013 4:34 am
Forum: SparkFun Product Questions
Topic: Serial Oscilloscope
Replies: 1
Views: 401

Serial Oscilloscope

This post is just to share the Serial Oscilloscope I wrote over the weekend. It is a Windows application that plots received data as up to 9 channels on an oscilloscope. It also functions as a basic serial terminal to send and receive bytes. I created it as a general purpose tool for debugging any p...
by sebmadgwick
Wed Mar 06, 2013 4:48 am
Forum: SparkFun Product Questions
Topic: RFID for library books
Replies: 1
Views: 312

Re: RFID for library books

I tested sparkfuns 13.56 MHz RFID reader with the example code which needed a fix. It would repsond to every RFID thing I could find (bank cards to passport) except the library book tags.
by sebmadgwick
Tue Jan 15, 2013 7:48 am
Forum: SparkFun Product Questions
Topic: RFID for library books
Replies: 1
Views: 312

RFID for library books

I would like to make an RFID scanner to read the tags on library book. I know that the tags are 13.56 MHz and ISO 28560 for libraries . Does this mean that sparkfuns 13.56 MHz RFID reader is not compatible? Please can someone recommend me a suitable RFID reader I can hook up to my microcontroller. T...
by sebmadgwick
Thu Nov 15, 2012 4:30 pm
Forum: Wireless/RF
Topic: XBee channel crosstalk
Replies: 1
Views: 412

XBee channel crosstalk

I have an XBee (XB24-API-001) node streaming bytes and a node (XStick) printing received bytes to a terminal. Changing each nodes channel results in the expected behaviour. However, bytes sent on channel 21 can be received on channel 13 if the nodes are close to each other, this transfer fails when ...
by sebmadgwick
Thu Nov 15, 2012 12:17 pm
Forum: SparkFun Product Questions
Topic: Do XBee internal pull-ups work for analogue inputs?
Replies: 2
Views: 505

Re: Do XBee internal pull-ups work for analogue inputs?

I tested them while floating externally and they behaved as floating. I mainly use Microchip devices and was surprised when I found out that Arduino pull-ups apply to analogue, I wondered if XBee were the same... I guess not.
by sebmadgwick
Thu Nov 15, 2012 5:34 am
Forum: SparkFun Product Questions
Topic: Do XBee internal pull-ups work for analogue inputs?
Replies: 2
Views: 505

Do XBee internal pull-ups work for analogue inputs?

I have my XBee radio streaming its 6 analogue inputs and my PC displaying these values on a real-time graph. A potentiometer (between VDD and GND) on each channel gives the expected behaviour. It would be useful to use the internal pull-ups for other types of sensors but it seems that the pull-ups a...
by sebmadgwick
Tue Oct 23, 2012 4:30 am
Forum: Wireless/RF
Topic: XBee - which PAN should I use?
Replies: 4
Views: 824

Re: XBee - which PAN should I use?

Thanks for the info but this is not quite the answer I am looking for. I understand how the XBee modules work and how various configurations can be useful to me. I want to know if certain channels and/or PAN IDs are more likely to be a problem than others in public environments. For example, it is o...
by sebmadgwick
Mon Sep 17, 2012 9:55 am
Forum: Wireless/RF
Topic: XBee - which PAN should I use?
Replies: 4
Views: 824

XBee - which PAN should I use?

I am creating a system where multiple wireless sensors stream data to a host computer displaying real-time graphics. I am using XBee series 1 modules in a P2P arrangement with one USB dongle per sensor (due to bandwidth limitations). Each XBee sensor will operate on a different channel. I have left ...
by sebmadgwick
Tue Jul 17, 2012 3:42 pm
Forum: SparkFun Product Questions
Topic: MPU-6050 thermal chamber results – Hysteresis
Replies: 21
Views: 5985

Re: MPU-6050 thermal chamber results – Hysteresis

My current thinking is that the behaviour is accounted for by the random walk in some way being excited by the dynamics. I have found that the temperature curve seems to be repeatable but that it is ‘shifted’ up or down by a limited amount giving the impression of a hysteresis if only a limited numb...
by sebmadgwick
Mon May 28, 2012 6:46 am
Forum: SparkFun Product Questions
Topic: L3G4200D angle calculation
Replies: 1
Views: 1268

Re: L3G4200D angle calculation

The following may not be the main cause of your problem but the 12.5 Hz bandwidth (i.e. low-pass filter cut-off at 25 Hz) seem very low for typical applications, as does the 250 dps range. I would advise that you define a bandwidth a quarter that of your sample rate (i.e. 50 Hz cut-off frequency for...
by sebmadgwick
Sun May 13, 2012 6:15 am
Forum: SparkFun Product Questions
Topic: How many XBees can be used in same room?
Replies: 2
Views: 407

Re: How many XBees can be used in same room?

Thanks for the info. It sounds we should be OK. I will only be able to spare a couple of days to design and make these wireless controllers so I want to be happy that I don’t start in the wrong direction.
by sebmadgwick
Sat May 12, 2012 4:28 pm
Forum: PIC Microcontrollers - Software and Hardware
Topic: Which PIC to start with?
Replies: 16
Views: 6926

Re: Which PIC to start with?

Whatever you pick, don't start with an 8-bit device. I completely disagree with the apparent notion some people have that a starting device should be as limited as possible so as not to appear too daunting. There are just so many resources on-line today that any novice can pick up the most complicat...
by sebmadgwick
Sat May 12, 2012 3:48 pm
Forum: SparkFun Product Questions
Topic: How many XBees can be used in same room?
Replies: 2
Views: 407

How many XBees can be used in same room?

I wish to create system where there will be many screens in a room, each with its own wireless controller. I am considering using XBee (series 1) for the task and using a different network address for each P2P pair. I doubt there would be more than 20 pairs in a room. I wondered if anyone has any ex...
by sebmadgwick
Fri Apr 06, 2012 12:46 pm
Forum: SparkFun Product Questions
Topic: MPU-6050 thermal chamber results – Hysteresis
Replies: 21
Views: 5985

Re: MPU-6050 thermal chamber results – Hysteresis

There are no “time lags”. The rate of heating is many orders of magnitude below any relevant time constants. Each measurement is the mean of 1000 samples taken over 2 seconds, the rate of heating is less than 0.5˚C per minute and the thermometer is built into the MPU-6050’s 5mm x 5mm package.
by sebmadgwick
Sat Mar 31, 2012 6:19 pm
Forum: SparkFun Product Questions
Topic: MPU-6050 thermal chamber results – Hysteresis
Replies: 21
Views: 5985

Re: MPU-6050 thermal chamber results – Hysteresis

1) Time lag from the temperature change. If the data you have presented is using the on board temp sensor this is less likely. But a lag in the response of the PCB causing stress is still a possibility. The temperature measurements are provided by the MPU-6050’s internal thermometer. The PCB layout...