要在MicroPython中进行AWS签名请求，您需要使用AWS的标准签名算法来生成请求的签名。下面是一个示例代码，展示了如何在MicroPython中使用urequests库进行AWS签名请求。

import time
import hmac
import hashlib
import urequests

# AWS凭证
access_key = ""
secret_key = ""

# 请求信息
http_method = "GET"
endpoint = "https://"
path = "/"
query_string = "Param1=value1&Param2=value2"
content_type = "application/json"
payload = ""

# 生成签名
def generate_aws_signature(http_method, endpoint, path, query_string, content_type, payload):
    timestamp = str(int(time.time()))
    canonical_request = http_method + "\n" + path + "\n" + query_string + "\n" + "content-type:" + content_type + "\n\n" + payload
    string_to_sign = "AWS4-HMAC-SHA256\n" + timestamp + "\n" + timestamp[:8] + "/us-east-1/execute-api/aws4_request\n" + hashlib.sha256(canonical_request.encode()).hexdigest()
    signing_key = hmac.new(("AWS4" + secret_key).encode(), timestamp[:8].encode(), hashlib.sha256).digest()
    signature = hmac.new(signing_key, string_to_sign.encode(), hashlib.sha256).hexdigest()
    authorization_header = "AWS4-HMAC-SHA256 Credential=" + access_key + "/" + timestamp[:8] + "/us-east-1/execute-api/aws4_request, SignedHeaders=content-type, Signature=" + signature
    return authorization_header

# 发送签名请求
def send_signed_request(http_method, endpoint, path, query_string, content_type, payload):
    headers = {
        "Content-Type": content_type,
        "Authorization": generate_aws_signature(http_method, endpoint, path, query_string, content_type, payload)
    }
    url = endpoint + path + "?" + query_string
    response = urequests.request(http_method, url, data=payload, headers=headers)
    return response

# 发送签名请求并处理响应
response = send_signed_request(http_method, endpoint, path, query_string, content_type, payload)
print(response.text)

请注意，此示例代码假设您已经在MicroPython设备上安装了urequests库。如果您尚未安装此库，请先安装。

此示例代码中的access_key和secret_key是您自己的AWS凭证，您需要将其替换为您自己的凭证。endpoint是您要请求的AWS服务的端点地址，path是API的路径，query_string是查询字符串参数。您还可以根据需要修改content_type和payload。

生成签名的函数generate_aws_signature使用AWS的标准算法生成签名，并返回授权头部。发送签名请求的函数send_signed_request使用urequests库发送带有签名授权头部的请求，并返回响应。

请根据您的具体情况修改示例代码中的参数，并确保您的设备上已安装所需的库。