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chumbysphere forum → Service, Warranty & Repair → Bend Sensor Testing
A friend has handed her Chumby over to me. She is more of a craft person and I am more of technical person. The Chumby is now powered and chilling with my on my desk. As it was sent to a crafter, it's not in a leather case, yet exposed to the world. It's still safe, yet I have not been able to test the "Squeeze" ability. I'm worried the Bend Sensor might be damaged, and I don't know how to test it.
I would be thankful for some suggestions.
bunnie might pipe in with some advice, but you should be able to disconnect the bend sensor from the daugherboard, and use a common ammeter to test the resistance of the bend sensor through the contacts - it *should* vary as you bend it.
Assuming the bend sensor has been removed from the fabric, do you see anything obviously kinked or broken?
If you can successfully ssh into the chumby (instructions on how to start up sshd are on the wiki), you can simply "cat /dev/bend" to see the values it's generating.
Since the bend sensor is normally used to bring up the Control Panel, and you think it's not working, there is another way - use a stylus to press the upper left corner of the display. You should then be able to start sshd using the Settings->Info Easter Egg.
Assuming the bend sensor has been removed from the fabric, do you see anything obviously kinked or broken?
Thanks! The bend sensor has been removed; more specifically, it was never in fabric. The sensor looks like it is in good shape. About midway down there looks to be a small crease. It looks like it was folded over, unprinted side to unprinted side. Nothing looks broken thou.
I will disconnect it and put it on my meter when I get home from work.
Since the bend sensor is normally used to bring up the Control Panel, and you think it's not working, there is another way - use a stylus to press the upper left corner of the display. You should then be able to start sshd using the Settings->Info Easter Egg.
I have been using the left corner tap to bring up the control panel and that's working just fine. I have read the Easter Egg and will try the sshd.
Thanks again.
If you can successfully ssh into the chumby (instructions on how to start up sshd are on the wiki), you can simply "cat /dev/bend" to see the values it's generating.
This might be above and beyond your support...
I'm using my Mac to attempt the SSH connection, using Terminal. I am in no way savy to linux or it's commands. I learn quick thou! Here's what I am seeing:
I think problem #1, using Internet Connection Sharing throu my Airport, which may be sending out on g-band. #2, I have my Mac at work, behind a router that has IP addresses assigned (192.168.1.102 being one of our printers), so there may be a conflict. Perhaps I will disable the Ethernet connection and test some more.
On the chumby, go to the Settings->Info screen, and you should see the IP that's been assigned to the chumby.
If you touch the legs of the chumby icon in the background of the Info screen in the order 1,1,2,3,5, then you should get a little logo that blinks at you - that means that sshd has been launched. If you get it wrong, hit leg 6 and start over.
For instance, let's say it gets the IP 192.168.1.104
Open a Terminal window on your Mac, then type:
ssh 192.168.1.104 -l root
You should get a big ASCII chumby logo, then a prompt.
Type:
rm /tmp/flashplayer_started
killall chumbyflashplayer.x
This shuts down the current player, and prevents it from restarting automatically. We need to shut it down so that it frees up the bend sensor driver.
Now you should be able get output from the bend sensor with:
cat /dev/bend
Use CTRL-C to interrupt.
You can restart your chumby with:
reboot
Hmmm... no IP address has been assigned to my Chumby.
I've been attempting to use the Internet Connection Sharing in OSX. My mac is connected to a LAN (IP: 192.168.1.110), and using my Airport card to create an AP (IP: 10.0.2.1, 802.11g). The Chumby can see the SSID of the AP, yet it cannot connect. I think this is due to the Airport only using Wireless-G. Our office does not use a WAN.
Can I create a USB connection?
Hmmm, that's a problem - due to a bug in the network driver, the current prototype chumby only supports 802.11b or b/g mixed mode. We have someone working on the problem, but it currently appears that this driver might be hopeless for g mode support under Linux 2.4. Unfortunately, this is the only network method currently supported.
There is a way to use a TTL-level serial port (*not* RS-232) to bring up a console, but that requires some specialized cabling or a hacked up USB serial device. bunnie makes them for us software guys by opening up USB serial devices and patching directly into the RX and TX pins on the serial chip, bypassing the driver circuitry. The serial port on the chumby is along the top edge of the main circuit card just to the right of the middle - you'll see a row of pads under the RF shield.
I'll look for it. If I can reset my wireless router at home to 802.11b, then I wouln't need to... I will let you know how it pans out for me.
Okay, I did all these steps, but it gives me an error. No /dev/bend file found. Has the hardware changed since this was posted?
It was my understanding that there was a squeeze sensor on the chumby (from the site docs), but we just got ours and it appears to be a switch (values of either on or off). I thought this was a pressure sensitive sensor. No?
I think it was a bend sensor in the early prototypes, but the production model just has a switch - the bend sensor was too delicate, it seems...
The original prototypes had an analog bend sensor - however it was too fragile, too expensive, and sourced from a single vendor.
This thread confirms it - in this case the sensor was damaged due to over-enthusiastic squeezing.
We replaced it with a switch in the production units.
This thread, which is very old, refers to the prototypes, not the production units.
Hmm, that stinks. On your product page it says "squeeze sensor" (http://store.chumby.com/) which I presumed would be a standard pressure or strain sensor. Instead, it's a toggle switch.
Unfortunately, this is one of the reasons we purchased a Chumby. We had a specific app in mind to use the accelerometer and squeeze sensor.
Has anyone hooked up an actual pressure sensor to a Chumby? Are there instructions for something like this?
Or can we get a refund? I would hate to give up on him. He's such a cute little guy. 
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