# Full sized USB Host Shield with 5 volt UNO R3

**URL:** <https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488>\
**Category:** 3rd Party Boards\
**Created:** [September 13, 2026, 11:52pm UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488 "2026-09-13T23:52:44Z")\
**Posts on this page:** 9\
**Page:** 2

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**Author:** ![customcontroller](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/customcontroller/32/1013044_2.png) [@customcontroller](https://forum.arduino.cc/u/customcontroller)\
**Post date:** [September 17, 2026, 9:14pm UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488/21 "2026-09-17T21:14:16Z")

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There are a small number of options for USB host on Arduino boards without using the USB host shield. But software support is extremely limited. Nothing supports the range of devices that the USB Host Shield Library 2.0 supports. And the UHS2 library only works using MAX3421E. If you say what you want to do with USB host, there may be other solutions.

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**Author:** ![Deva\_Rishi](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/deva_rishi/32/227254_2.png) [@Deva\_Rishi](https://forum.arduino.cc/u/Deva_Rishi)\
**Post date:** [September 17, 2026, 9:48pm UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488/22 "2026-09-17T21:48:13Z")

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I actually put a couple of 74A125 soic-8 in my shopping cart, pity about the new European tax, but i think it's still worth it. I have a blower and those are easy enough to replace. Don't know what the OP is intending to do.

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**Author:** ![AaronMichael](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/aaronmichael/32/1129305_2.png) [@AaronMichael](https://forum.arduino.cc/u/AaronMichael)\
**Post date:** [September 17, 2026, 10:07pm UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488/23 "2026-09-17T22:07:26Z")

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The USB Host and Uno R3 combination have been working fine for years for me. My needs are pretty simple I'm reading a standard PC USB keyboard in, translating the data and sending it out on a serial line at 32KHz. Not demanding at all.

A thought occurred to me but I've only studied the schematic a little. Is the 5v on the Host board to power the USB port and to up the output to the UNO? Suppose you separated the 5v to the USB port and fed the 74HC125 VCC with 3.3v. Won't the UNO still read the 3.3v output as on? Is this a simple fix? What am I missing? Thanks for you comments, Aaron

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**Author:** ![AaronMichael](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/aaronmichael/32/1129305_2.png) [@AaronMichael](https://forum.arduino.cc/u/AaronMichael)\
**Post date:** [September 17, 2026, 10:10pm UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488/24 "2026-09-17T22:10:26Z")

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Please, what is the OP you mention? And what is a blower? Sorry, English is not my first language. Thanks, Aaron

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**Author:** ![customcontroller](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/customcontroller/32/1013044_2.png) [@customcontroller](https://forum.arduino.cc/u/customcontroller)\
**Post date:** [September 17, 2026, 11:00pm UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488/25 "2026-09-17T23:00:20Z")

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The Giga R1 WiFi is a big expensive board with a USB host port and UARTs. USB keyboard is supported by the library USBHostGiga. You can install the library using the IDE library manager then look at the examples to see if has the features you need without buying a Giga board. The board works with 3.3V so external circuits must be modified to work with this board.

I have not heard of any other fix for dead USB host shields except to replace the 74HC125 near the ICSP connector.

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**Author:** ![AaronMichael](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/aaronmichael/32/1129305_2.png) [@AaronMichael](https://forum.arduino.cc/u/AaronMichael)\
**Post date:** [September 18, 2026, 3:46am UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488/26 "2026-09-18T03:46:48Z")

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> [@AaronMichael](#):
>
> A thought occurred to me but I've only studied the schematic a little.

Oops! Far to little. I misread the schematic and confused myself. Never mind.

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**Author:** ![Deva\_Rishi](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/deva_rishi/32/227254_2.png) [@Deva\_Rishi](https://forum.arduino.cc/u/Deva_Rishi)\
**Post date:** [September 18, 2026, 7:25am UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488/27 "2026-09-18T07:25:43Z")

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> [@AaronMichael](#):
>
> Please, what is the OP you mention

OP stands for 'Original Poster' (or something like that) and in this case it's you i guess.

> [@AaronMichael](#):
>
> And what is a blower?

A tiny [temperature controlled heat-gun](https://nl.aliexpress.com/item/1005011863188554.html?spm=a2g0o.productlist.main.11.37745e12iWeOHD&algo_pvid=1b2cb99b-88d1-4e61-8d94-3a5716a7c949&algo_exp_id=1b2cb99b-88d1-4e61-8d94-3a5716a7c949-10&pdp_ext_f=%7B%22order%22%3A%222108%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&pdp_npi=6%40dis%21EUR%2137.59%2136.79%21%21%21282.17%21276.20%21%402103810f17897152965666762e1079%2112000057510219650%21sea%21NL%21762934668%21X%211%210%21n_tag%3A-29919%3Bd%3A4d28a69c%3Bm03_new_user%3A-29895&curPageLogUid=hUn8AOgAcS6Q&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005011863188554%7C_p_origin_prod%3A) something like this. Mine has the display separated from the holder, and i guess they are all a little different, but if you heat up the PCB and the legs of soic-14 chip sufficiently, (actually for removal i use almost the maximum heat setting since the IC can get as hot as long as i don't intent to use it again) and at some point if you gently pull it a little with tweezer, the whole thing comes off without damaging the PCB. Then adding a bit of flux (the PCB has been cleaned from any flux, and for the re-solder we do need some) and cleaning up the pads of the PCB, the new IC can be soldered on by simply holding it in place with a little downward pressure and heating up again until the solder flows to connect the legs. (this with the gun at a reduced temperature)  
It does take some practice, you don't want to pull to hard on the old IC or you will damage the PCB, you don't want to much solder or legs will start to short, and the settings for your heatgun will require experimentation.

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**Author:** ![AaronMichael](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/aaronmichael/32/1129305_2.png) [@AaronMichael](https://forum.arduino.cc/u/AaronMichael)\
**Post date:** [September 19, 2026, 12:52am UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488/28 "2026-09-19T00:52:13Z")

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Thanks for the education. Back when I was young, (last century) a blower was a telephone. Your blower certainly makes working with small SMT's a lot easier. I wonder if I could succeed with one with my limited vision. On my previous jobs (again in the last century) we designed our boards with thru hole chips, made our boards in house, and assembled the finished product in house. But then we were making custom products for industry and research. And I never did much logic, and what I did was TTL. Then we were using 8051s and programming in ASM. So a lot new stuff has happened since, in the last 30-40 years. Thanks again, Aaron

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<div class="post-metadata">

**Author:** ![Deva\_Rishi](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/deva_rishi/32/227254_2.png) [@Deva\_Rishi](https://forum.arduino.cc/u/Deva_Rishi)\
**Post date:** [September 19, 2026, 7:10am UTC](https://forum.arduino.cc/t/full-sized-usb-host-shield-with-5-volt-uno-r3/1459488/29 "2026-09-19T07:10:12Z")

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> [@AaronMichael](#):
>
> I wonder if I could succeed with one with my limited vision.

A good magnifying glass helps a lot, but some vision is required, i don't know how bad it is. You need a clear vision of individual legs. I tend to verify the solder has flowed properly between the legs and the PCB using a DMM. If you can manage that, then your vision is good enough.

> [@AaronMichael](#):
>
> we designed our boards with thru hole chips,

SMT saves a lot of space and also quite a bit of time. Definitely easier to remove an SMD than a THT chip (unless that on is in a socket)

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