# Arduino Pocket Reference vs 555 Timer & Oscillators Guide

The clearest difference is in-app purchases: 555 Timer & Oscillators Guide at none against Arduino Pocket Reference's 1. Arduino Pocket Reference's advantage is iOS requirement (14.0 vs 16.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Arduino Pocket Reference sells 1 one-off in-app purchase. 555 Timer & Oscillators Guide asks for nothing beyond the download.

Both ship on a similar rhythm, roughly every 5 months. The most recent releases landed on June 2, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | Arduino Pocket Reference | 555 Timer & Oscillators Guide |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[2.4 (17 ratings)](https://appshunter.io/ios/app/arduino-pocket-reference/id969849288/reviews)** | — |
| Number of ratings | **17** | — |
| Positive reviews | 12.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | Yes |
| Update frequency | Every 5 months | Every 5 months |
| Monetization | Free with in-app purchases | — |
| Size | 78 MB | 24 MB |
| Requires iOS | **14.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | +4 |
| Developer | [Vipin Nair](https://appshunter.io/developer/841810400) | [ALG Software Lab](https://appshunter.io/developer/1650561236) |

## What reviewers say

### Arduino Pocket Reference

[App page](https://appshunter.io/ios/app/arduino-pocket-reference/id969849288)

This app provides a comprehensive reference for Arduino programming, covering core libraries, syntax, operators, and various hardware shields. It includes examples for common functionalities like mouse control, GSM communication, and LCD displays, making it a valuable tool for makers and developers.

**Highlights:** Arduino core libraries list, Mouse and Keyboard control examples, GSM communication examples, LiquidCrystal library functions, Syntax, operators, and data types, Various Arduino board guides, IO and math functions

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Advertisements | $0.99 | one-time |


### 555 Timer & Oscillators Guide

[App page](https://appshunter.io/ios/app/555-timer-and-oscillators-guide/id6504487994)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Arduino Pocket Reference free?

Arduino Pocket Reference is free to download, with in-app purchases available.

### Is 555 Timer & Oscillators Guide free?

555 Timer & Oscillators Guide is free to download, with no in-app purchases.

### Do Arduino Pocket Reference or 555 Timer & Oscillators Guide have ads?

Both Arduino Pocket Reference and 555 Timer & Oscillators Guide show ads.

### Which is updated more often, Arduino Pocket Reference or 555 Timer & Oscillators Guide?

Arduino Pocket Reference ships an update every 5 months, and 555 Timer & Oscillators Guide every 5 months. Most recently, Arduino Pocket Reference was updated on June 2, 2026 and 555 Timer & Oscillators Guide on September 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*