Looking For Small Barcode Reader ICs - Page 1
Forum section: electronics / repair

author: fmashockie
author_rank: Frequent Contributor
timestamp: June 08, 2024, 03:32:09 am
content: Hello EEV Blog! I am in the process of attempting to repair a piece of lab equipment at work. It is a PerkinElmer Envision 2104 plate reader. The unit has a ton filters and mirror modules. All these filters and mirror modules are barcoded so the instrument can recognize which ones are installed and in use. However, one of these barcode readers is having an issue. The mirror modules sit on a wheel that rotates (think like a cd changer or something). It uses a small barcode reader IC to both read the barcodes on the mirror modules and to home itself to the zero position.After extensive troubleshooting I am pretty confident the barcode reader is faulty. It is a 4-pin IC. It had no identifying markings until I desoldered it and found 'Shinkoh Elect' on the bottom. I looked up their website and found what is likely the IC. It is called the KR1228https://www.shinkoh-elecs.jp/en/technology/feature/According to their website, it is a red 'LED and phototransistor' combined.I have yet to reach out to the company for availability, but I was wondering if anyone is familar with ICs like this. I couldn't find anything like it on Mouser or Digikey (maybe I wasn't using the correct search terms?). It would nice to have alternatives to the KR1228 in the event the manufacturer cannot provide in small quantities. If anyone could help point me in the right direction I would greatly appreciate it!I attached some photos of it as well. The alternative has to be a 4 pin IC LED/phototransistor like this.Thanks!-Frank

author: Whales
author_rank: Super Contributor
timestamp: June 08, 2024, 03:52:34 am
content: Looks like an LED and phototransistor. AKA a "reflective IR sensor".It probably doesn't have any brains in it, but it's a part that's known to go bad in a lot of things.If you can't find a replacement with the same footprint then you might be able to replace it with a 3mm IR LED and a 3mm IR phototransistor cleverly positioned and bent.

author: fzabkar
author_rank: Super Contributor
timestamp: June 08, 2024, 04:06:49 am
content: https://www.sensorinstock.it/en/photo-reflector/541-kr1228.htmlhttps://www.shinkoh-elecs.jp/wp-content/uploads/2015/07/C_KR1228_1229_20B.pdf(datasheet)

author: tooki
author_rank: Super Contributor
timestamp: June 08, 2024, 09:10:24 am
content: Quote from: Whales on June 08, 2024, 03:52:34 amYou need optics to focus on a single spot, or a slit to accomplish the same (and then, only if it’s in very close contact). Otherwise you’re getting the unfocused result of the entire illumination area, which is useless for reading a bar code.

author: fmashockie
author_rank: Frequent Contributor
timestamp: June 08, 2024, 12:37:49 pm
content: Quote from: fzabkar on June 08, 2024, 04:06:49 amYou are the king of finding/identifying components. Thank you so much for this!

author: fmashockie
author_rank: Frequent Contributor
timestamp: June 08, 2024, 11:11:53 pm
content: Quote from: tooki on June 08, 2024, 09:10:24 amThanks for this. Plus I already mentioned it was a red LED in the description. Not IR LED. Specifically need it for barcode reading. I'm surprised I can't find anything similar in any of the major distributors like Mouser/Digikey. But I think I'll try the distributor that Fzabkar mentioned. Was hoping for something that wasn't international, but I'll take it if it is the only option.

author: MAS3
author_rank: Regular Contributor
timestamp: June 09, 2024, 12:32:18 am
content: The focus is what's important, the colour of the light not that much.I'm sure IR would work as well as red, provided the receiver is shielded from the transmitter (that's what you can see in the centre of the lens in your 2nd. picture), so that it only sees what's reflected and what not by the bar code it's scanning.The transmitting LED most of the times goes bad or dies and the part becomes worthless.This sort of components are often used for homing all kinds of stuff, and are often the weakest point in the devices they are used in.OTOH, it's also often an easy fix.

author: fmashockie
author_rank: Frequent Contributor
timestamp: June 09, 2024, 02:14:41 am
content: Quote from: MAS3 on June 09, 2024, 12:32:18 amThanks MAS3. The LED on this one still works. I'm not 100% sure if it is the reason for the issue I am seeing. But after much troubleshooting it doesn't seem like anything else is the cause. I can see the output signal making it to the microcontroller via scope. But perhaps it is too broad, not strong enough, etc. Very annoying.I was just looked up IR vs red light for barcode scanners. And I actually might want to give an IR-based sensor a try. Apparently, they are better for when the ambient light is not as good. This scanner sits in complete darkness because it is inside a spectrophotometer (can't have stray light affecting mesaurements).