Guys Please tell me is my digispark is a goner, i think i fried it

[Mahimna]

I connected the digispark's 5v pin to one end of the coil of a relay and GND to the other end and was testing with the multi-meter that whether the Normally Open and center are getting in contact or not? as it was not in contact, I tested the coil i.e 5v pin and GND pin for what voltage it is showing but I forgot to switch it to voltage setting and it was on connectivity test setting only. when I realized nothing is happening, no sound for connection then I realized and switched it to voltage and now no voltage was observable across it. After that I plugged it again for reprogramming to use pin1 but now the codes are not getting uploaded at all. it is showing code 43 error in device manager and after many times deleting and reinstalling drivers it is still showing code 43 only. Have I fried it, beyond repairing ? and please tell me if the connection with the relay which i did were horribly wrong or what? so I can avoid it in future Please help me guys.

[Mahimna]

I just tested the voltage accros the 5v pin and GND of the digispark directly, it is showing exactly 2.49v. and when tested over relay coil it is showing 1.77v. Please tell me what is going on

[granzeier]

Try removing everything that is connected to the Digispark, and then try to upload the blink sketch from the Examples menu. For something like this, you cannot get good information with any external circuitry attached.
Let us know what happens, and we can go from there.

[Mahimna]

Hello, thanx for replying. I removed it from the project and now connected only the digispark to the usb and tried to upload the blink code. but unfortunately it always stuck on "uploading" and does not get complete. The digispark is also showing under unknown devices in device manager rather than lin32. it is showing "Windows has stopped this device because it has reported problems. (Code 43)". I reinstalled the drivers but the problem is as it is. I tested my friends digispark with the blink code from the same PC and it worked fine. So please tell me now what to do. Just to let you know, when I measured the voltage across the 5V and GND of the digispark it is showing 2.5V rather that 5V.

[granzeier]

...Just to let you know, when I measured the voltage across the 5V and GND of the digispark it is showing 2.5V rather that 5V.

When you borrowed your friend's Digispark, what voltage did you read across +5V and ground? (Sorry, but I do not have any of my Digisparks handy, and probably won't for a few days - spring cleaning my lab.)

If you read the same as with your Digispark, then the hardware will probably be fine.  If so then you may need to reload the bootloader in your Digispark.

[Mahimna]

well on the friend's Digispark it was exactly 5V. Oh please do explain me about the bootloader reinstalling. (Cause I don't think I can afford another one for a month or two, I am not that wealthy at all  ). I'' really appreciate your help.

[granzeier]

With the difference in voltage readings, I think that you may have blown your Digispark.

The schematic (https://s3.amazonaws.com/digispark/DigisparkSchematicFinal.pdf) does not show much in the way of fragile stuff. So, if your soldering skills are pretty good, you could change out the Tiny85, and see if that helps.

Once you do that, you will need to load the bootloader - https://digistump.com/board/index.php?topic=1414.0. You will need to follow the links to get all the info.

Or, you could go ahead and get a cheap clone (I got a few for under U$2.00 each.) That may help hold you over until you get a bit more cash to get some more real ones.

[PeterF]

If you connected the relay coil to the 5v and GND of the digispark and didn't use a diode to prevent against EMF backfeed/voltage spike from when the relay engages and releases, it'll be a 50/50 bet on whether you fried the regulator by basically shorting it out by having the meter on continuity instead of voltage sense, or whether the relay gave it a high voltage spike and fried the attiny85. As granzeier said, there's nothing delicate in the voltage path, it's pretty much just the attiny85 and the voltage regulator... If you leave the digispark plugged in for a minute with nothing connected to it, and the attiny85 (the 8 legged chip to the side) gets hot, then it's fried and needs replacing. If the other bigger component in the middle gets hot, then either the attiny85 is fried AND basically presenting as a short, or the regulator is fried.

Best bet is to just by another cheap clone from eBay - only (!!) AUD$1.78/USD$1.38 each inc. shipping.
Laid out just like the 'genuine' Digispark - US$1.38
Digispark *compatible* clone - US$1.59

[Mahimna]

Well, as you said it is getting hot indeed. Thank you both of you for your weigh ins. As you have recommended, I will purchase those digi clones. Even I found the 123d circuits simulator for arduino to dry run the code and hardware connections just to make sure that i'm not messing around with the digi again. I will let you know if I hit another road block in my journey.
thank you!

[Mahimna]

BTW guys if you can please help me with my issue I have addressed in project section with "Interrupt delay and confusion". I have managed a way out but its not efficient and optimised.
https://digistump.com/board/index.php/topic,2885.0.html