555 Calc vs AVR Tutorial
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
555 Calc
This utility app helps engineers and hobbyists calculate resistor values for circuits using the Timer IC 555. Simply input frequency, duty ratio, and capacitor values to get the required resistor outputs.
- Calculate resistor values
- Input frequency
- Input duty ratio
- Input capacitor value
- Timer IC 555 circuit design
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This App calculates registors value, when designing the circuit using Timer IC 555. How to (1) Input Frequency value. (2) Input Duty Ratio. (3) Input C1 Value. (4) Touch ‘Calculate’ button. (5) Registors value will be displayed. Note. * Set Duty Ratio to 50 ~ 99. * If you set Duty Ratio to 50, R1 value will be set to 0.
AVR Tutorial
This app simplifies learning AVR microcontrollers with a code wizard that generates C source code for various peripherals. It offers demo projects and an architecture review, making complex MCU programming more accessible for hobbyists and students.
- AVR architecture review
- AVR assembly and C language
- 21 demo projects
- Code wizard for peripherals
- Portability to other ATMEGA MCUs
- I2C and SPI EEPROM support (PRO)
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This app is a AVR tutorial based on ATMEGA16 C language. It is suitable for hobbyist or engineering students. Learning AVR mcu is difficult. The learning curve is steep. The process including reading datasheet, writing code, building prototypes and troubleshooting. The most possible errors are the setting wrong value of registers. Now, AVR tutorial is the solution. The code wizard allow you to set the timer, UART, ADC, interrupt and peripherals by just a few clicks in setting. The proven C source code is generated automatically. Though the code wizard is based on ATMEGA16 mcu, it is easy to port to other ATMEGA mcu since the source code is highly structured Features • AVR architecture review • AVR asm mnemonics & C language • 21 demo projects including LED, buzzer, key switch, lcm16x2, ADC, etc • Code wizard for UART, timer, interrupt, ADC and external peripherals Features in PRO only • Support I2C eeprom 24C01 (128B) ~ 24C512 (64kB) • Support SPI eeprom 25010 (128B) ~ 25M02 (256kB) • Extra demo projects including led matrix 16x16, I2C eeprom, SPI eeprom • Code wizard for I2C eeprom, SPI eeprom, LCM128x64, etc Atmel® and AVR® are registered trademarks or trademarks of Atmel Corporation or its subsidiaries, in the US and/or other countries. This application is not related or affiliated in any way Atmel Corporation.
Screenshots
Verdict
The clearest difference is rating: AVR Tutorial at 5.0 against 555 Calc's 4.0. AVR Tutorial also leads on ads (none vs shown) and update cadence (every 3 months vs every 20 months). 555 Calc's advantage is in-app purchases (none vs 10). On price, ratings volume and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. AVR Tutorial sells 10 one-off in-app purchases. 555 Calc asks for nothing beyond the download.
AVR Tutorial holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 3 and 2 respectively. Written reviews point the same way: 50% of 555 Calc's written reviews are positive against 75% of AVR Tutorial's.
555 Calc ships an update every 20 months, AVR Tutorial every 3 months. The most recent releases landed on September 27, 2026 and September 24, 2026 respectively.
| Parameter | 555 Calc | AVR Tutorial |
|---|---|---|
| Price | Free | Free |
| Rating | 4.0 (3 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 50.0% of reviews | 75.0% of reviews — better |
| Number of ratings | 3 — better | 2 |
| Update frequency | Every 20 months | Every 3 months — better |
| Ads | Yes | No — better |
| In-app purchases | No — better | Yes |
| Monetization | Ad-supported — better | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 11.0 | 9.0 — better |
| Further details — not scored | ||
| Size | 18 MB | 33 MB |
| Age rating | 4+ | 4+ |
| Developer | Jibiki Works | Siu Yuen Ho |
Customer experience
555 Calc
AVR Tutorial
In-app purchases
555 Calc
No in-app purchases
AVR Tutorial
- Unlock PRO feature$1.99
- SPI OLED$1.99
- I2C OLED$1.99
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- Wifi home automation$1.99
- 2.2" TFT$1.99
- LoRa home automation$1.99
- Home automation using Siri$2.99
- Home automation using Google$2.99
- BT home automation$4.99
- BLE home automation$4.99
Questions
Is 555 Calc free?
Is AVR Tutorial free?
Which has better reviews, 555 Calc or AVR Tutorial?
Do 555 Calc or AVR Tutorial have ads?
Which is updated more often, 555 Calc or AVR Tutorial?
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